Near-Room-Temperature Ferrimagnetic Ordering in a B‑Site-Disordered 3d−5d-Hybridized Quadruple Perovskite Oxide,CaCu3Mn2Os2O12

Lei Gao,†,‡ Xiao Wang,†,‡ Xubin Ye,†,‡ Weipeng Wang,† Zhehong Liu,†,‡ Shijun Qin,†,‡ Zhiwei Hu,§

Hong-Ji Lin,∥ Shih-Chang Weng,∥ Chien-Te Chen,∥ Philippe Ohresser,⊥ Francois Baudelet,⊥

Richeng Yu,†,‡ Changqing Jin,†,‡,# and Youwen Long*,†,‡,#

†Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190,China‡School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China§Max Planck Institute for Chemical Physics of Solids, Dresden 01187, Germany∥National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan, Republic of China⊥L’Orme des Merisiers, Synchrotron SOLEIL, Saint-Aubin, Gif-sur-Yvette Cedex 91192, France#Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China

ABSTRACT: A new 3d−5d hybridization oxide, CaCu3Mn2Os2O12 (CCMOO), wasprepared by high-pressure and high-temperature synthesis methods. The compoundcrystallizes to an A-site-ordered but B-site-disordered quadruple perovskite structure with aspace group of Im3 (No. 204). The charge states of the transition metals are determined tobe Cu2+/Mn3.5+/Os4.5+ by X-ray absorption spectroscopy. Although most B-site-disorderedperovskites possess lower spin-ordering temperatures or even nonmagnetic transitions, thecurrent CCMOO displays a long-range ferrimagnetic phase transition with a criticaltemperature as high as ∼280 K. Moreover, a large saturated magnetic moment is found tooccur [7.8 μB/formula units (f.u.) at 2 K]. X-ray magnetic circular dichroism shows aCu2+(↑)Mn3.5+(↑)Os4.5+(↓) ferrimagnetic coupling. The corner-sharing Mn/OsO6 octahe-dra with mixed Mn and Os charge states make the compound metallic in electrical transport, in agreement with a specific heatfitting at low temperature. This work provides a rare example with high spin-ordering temperature and a large magnetic momentin B-site-disordered 3d−5d hybridization perovskite oxides.

1. INTRODUCTION

In the past decades, perovskite and perovskite-like oxides havereceived much attention because of the wide variety of physicalproperties and fascinating functionalities such as ferromagnet-ism,1,2 ferroelectricity,3,4 superconductivity,5 colossal magneto-resistance,6 multiferroicity,7 etc. An ideal ABO3 perovskite hasa cubic crystal structure with a Pm3m space group (see Figure1a). In this structure, the B site is often occupied by transitionmetals, with BO6 octahedral coordination dominating theelectronic properties, whereas larger-size alkali, alkali-earth,and/or rare-earth metals usually accommodate the A sitesustaining the structure frameworks.8 Compared with thestrongly correlated electronic effects in 3d electrons, 5delectrons are featured by enhanced spin−orbit coupling dueto the extended orbital distribution.9 Taking into account theremarkable physical and chemical differences between 3d and5d electrons, most A2BB′O6-like perovskites with hybridized3d−5d elements crystallize into an ordered structure in a rock-salt-type fashion (see Figure 1b).10 A series of interestingproperties are reported in these systems. For example, in theSr2Cr

3+B′5+O6 family, a high ferrimagnetic Curie temperature(TC) is observed to increase from 458 K for B′ = W11 to 635 K

for B′ = Re12 and even up to 725 K for B′ = Os.13 This recordTC observed in perovskite systems is due to the strongsuperexchange interactions between the half-occupied Cr 3dand Os 5d t2g electrons.

13

Furthermore, for a simple ABO3 perovskite or a B-site-ordered A2BB′O6 double perovskite, if 75% of the A site issubstituted by another transition metal, A′, one may obtain anAA′3B4O12-type A-site-ordered quadruple perovskite (seeFigure 1c) or an AA′3B2B′2O12-type A- and B-site-orderedquadruple perovskite (Figure 1d) with A′O4 square-planar andB/B′O6 octahedral units.8 The introduction of transitionmetals at the A′ site can trigger new magnetic and electricalinteractions via the A′−A′ and/or A′−B/B′ pathways inaddition to the conventional B/B′−B/B′ ones.14,15 As a result,these specially ordered quadruple perovskites exhibit manypeculiar properties such as A′−B intersite charge transfer,16,17

charge disproportionation,18 negative thermal expansion,etc.16,19 As is well-known, the B-site degree of order plays animportant role for the magnetism and electrical transport. The

Received: August 26, 2019Published: November 8, 2019

Article

pubs.acs.org/ICCite This: Inorg. Chem. 2019, 58, 15529−15535

© 2019 American Chemical Society 15529 DOI: 10.1021/acs.inorgchem.9b02576Inorg. Chem. 2019, 58, 15529−15535

Dow

nloa

ded

via

INST

OF

PHY

SIC

S on

Dec

embe

r 20

, 201

9 at

06:

12:1

2 (U

TC

).Se

e ht

tps:

//pub

s.ac

s.or

g/sh

arin

ggui

delin

es f

or o

ptio

ns o

n ho

w to

legi

timat

ely

shar

e pu

blis

hed

artic

les.

presence of B-site disorder can significantly suppress the long-range spin interaction, so most B-site-disordered perovskitesshow relatively low spin-ordering temperatures or evenbecome spin glass or nonmagnetic.20,21 For example, the B-site-ordered CaCu3Fe2Nb2O12 has a long-range ferrimagneticphase transition near 170 K, whereas paramagnetic behavioroccurs when the B-site Fe and Nb ions are distributeddisorderly.22 In this paper, a new 3d−5d-hybridized quadrupleperovskite oxide, CaCu3Mn2Os2O12 (CCMOO), was pre-pared. The structure, valence states, and magnetic, electrical,and specific heat properties are investigated in detail. We findthat although the compound crystallizes to an A-site-orderedbut B-site-disordered structure with randomly distributed Mnand Os ions at the B site, it exhibits a long-range ferrimagneticordering with a TC as high as 280 K.

2. EXPERIMENTAL SECTIONThe polycrystalline CCMOO was prepared by a high-pressureannealing method. High-purity (>99.9%) CaO, CuO, MnO2, andOs powders at a mole ratio of 1:3:2:2 were used as reaction materials,and appropriate KClO4 was added as an oxidizing agent. Thesereactants were finely mixed in an agate mortar. The mixed powderswere pressed into a Pt capsule with 4 mm diameter and 6 mm lengthand then treated at 5 GPa and 1473 K for 50 min. The high-pressureand high-temperature conditions were generated by a cubic-anvil-typehigh-pressure apparatus. The product was washed by dilutedhydrochloric acid to remove impurities.The sample quality and crystal structure were characterized by

powder X-ray diffraction (XRD) using a Huber diffractometer (CuKα1 radiation, 40 kV, 300 mA). The diffraction data were collected inthe angle (2θ) range from 10° to 100° with steps of 0.005°.Crystallographic parameters were analyzed by the Rietveld full-profilerefinement using the GSAS program.23 Selected area electrondiffraction (SAED) was carried out using a Philips CM200transmission electron microscope with a field-emission gun operatedat 200 keV. The valence states of the Cu, Mn, and Os transitionmetals were identified by X-ray absorption spectroscopy (XAS)performed at the National Synchrotron Radiation Research Center inTaiwan. The soft XAS at the Mn L2,3- and Cu L2,3-edges wasmeasured with a total electron yield at the BL11A beamline. The hardXAS at the Os L3-edges was measured with transmission geometry atthe BL07A beamline. The X-ray magnetic circular dichroism

(XMCD) spectra of Cu L2,3 and Mn L2,3 were recorded at thebeamline DEIMOS of Synchrotron SOLEIL in Paris, with atemperature of 20 K and a magnetic field of 6 T. The XMCDspectrum of Os L3 was measured at the beamline ODE ofSynchrotron SOLEIL, with a temperature of 10 K and a magneticfield of 1.3 T. Magnetic susceptibility and magnetization weremeasured using a Quantum Design superconducting quantuminterference device magnetometer (MPMS-VSM). The zero-field-cooling (ZFC) and field-cooling (FC) modes were adopted formagnetic susceptibility measurements. The resistivity and specific heatwere measured on a Quantum Design physical property measurementsystem (PPMS-9T). A standard four-probe method was applied forresistivity measurement.

3. RESULTS AND DISCUSSIONFigure 2 shows the powder XRD pattern measured at roomtemperature as well as the Rietveld refinement results of

CCMOO. All of the diffraction peaks can be well indexedbased on a cubic symmetry. Moreover, Rietveld analysisdemonstrates that the compound crystallizes to an AA′3B4O12-type A-site-ordered perovskite structure with space group Im3.This means that the Ca and Cu atoms are 1:3 ordered at A andA′ sites with special Wyckoff positions 2a (0, 0, 0) and 6b (0,0.5, 0.5), respectively, while the Mn and Os atoms aredisorderly distributed at the B site with a Wyckoff position of8d (0.25, 0.25, 0.25). To further determine the B-site Mn/Osdisorder, SAED was carried out along the [1, −1, 0] zone axisfor CCMOO. As shown in the inset of Figure 2, one cannotfind any discernible diffraction spots with (h + k + l) equalingan odd number, confirming that the B-site Mn and Os ions arearranged randomly over the octahedral coordination sites.21

The refined structural parameters of CCMOO are listed inTable 1. The lattice parameter of CCMOO that we obtained is7.3078 Å, which is slightly larger than that of the isostructuralcompound CaCu3Mn4O12 (7.241 Å) due to the partialsubstitution of Mn by Os ions with more extended 5d orbitalsat the B site.24 According to the bond-valence-sum (BVS)method,25 the valence state of Cu at the A′ site is calculated tobe +2.37, suggesting the formation of a Cu2+ state. The slightlylarge calculated value is attributed to the overbonding effectowing to the high-pressure synthesis condition.26 Since Mnand Os form a solid solution, one cannot calculate the reliable

Figure 1. Schematic crystal structures for the (a) ABO3 perovskite,(b) B-site-ordered rock-salt-type double perovskite A2BB′O6, (c) A-site-ordered quadruple perovskite AA′3B4O12, and (d) both A- and B-site-ordered quadruple perovskite AA′3B2B′2O12.

Figure 2. XRD pattern and structure refinement results of CCMOOat room temperature. The observed (black circles), calculated (redline), and difference (blue line) patterns are shown. The ticks indicatethe allowed Bragg reflections with space group Im3. The inset shows aSAED image along the [1, 1, 0] zone axis indicating Mn/Os disorderat the B site.

Inorganic Chemistry Article

DOI: 10.1021/acs.inorgchem.9b02576Inorg. Chem. 2019, 58, 15529−15535

15530

valence states for these two transition metals based on the BVSmethod.The L2,3 absorption edges of XAS are very sensitive to the

valence states and local coordination environments fortransition-metal ions.27−30 To further confirm the valencestates of Cu, Mn, and Os in CCMOO, XAS was measured.Figure 3a shows the Cu L2,3-edge XAS spectrum for CCMOOand a Cu2+ reference, CaCu3Ti4O12, with similar CuO4 square-

planar coordination.31 The two compounds exhibit similarspectral shape and energy position, suggesting the formation ofa Cu2+ state in CCMOO. Figure 3b presents the Mn L2,3-edgeXAS spectrum for CCMOO, together with a Mn3+ reference,LaMnO3

27, and a Mn4+ reference, Sr3Mn2O7, with MnO6octahedral coordination.32 In comparison, the L2- and L3-edge main peaks of CCMOO are located at intermediatevalues of energy with respect to these two references.Moreover, the absorption spectral profile of CCMOO can bereproduced by a simple superposition from those of LaMnO3and Sr3Mn2O7 with a 1:1 ratio, indicating the presence of anaverage Mn3.5+ state mixed by Mn3+ and Mn4+.33 To identifythe valence state of Os, La2MgOs4+O6 and Sr2FeOs

5+O6 areused as Os4+ and Os5+ references, respectively.34 As shown inFigure 3c, with increasing valence state from Os4+ to Os5+, thepeak of Os L3-edge gradually shifts toward higher energies. Thepeak position of CCMOO is located at an approximatelyintermediate energy value between La2MgOsO6 andSr2FeOsO6. Taking into account the charge balance, a mixedOs4.5+ valence state on average is assigned to CCMOO.Therefore, the XAS measurements demonstrate the chargecombination to be CaCu2+3Mn3.5+2Os

4.5+2O12 in the current A-

site-ordered but B-site-disordered quadruple perovskite. Assummarized by Vasala and Karppinen, for two transition-metalions to form an ordered perovskite structure, the chargediscrepancy between them, in general, should be ≥2.10 Thedisordered perovskite structure of CCMOO is consistent withthe smaller charge difference between Mn3.5+ and Os4.5+.The magnetism of CCMOO was studied by magnetic

susceptibility and magnetization measurements. Figure 4a

displays the ZFC and FC magnetic susceptibility curvesmeasured at 0.1 and 1 T. As the temperature decreases to TC ≈280 K, the susceptibility experiences a sharp increase,indicating the occurrence of a ferromagnetic-like phasetransition. At lower temperatures, the ZFC and FCsusceptibility curves measured at 0.1 T slightly separate fromeach other. However, once a larger magnetic field of 1 T isapplied to overcome the domain wall energy, these two curves

Table 1. Refined Structure Parameters of CCMOO at RoomTemperaturea

parameter value

a (Å) 7.30777(2)Oy 0.1782(5)Oz 0.3086(5)Uiso(Ca)/(100 × Å2) 0.0161(23)Uiso(Cu)/(100 × Å2) 0.0144(6)Uiso(Mn/Os)/(100 × Å2) 0.0164(2)Uiso(O)/(100 × Å2) 0.0127(10)Cu−O/(×4 Å) 1.9107(26)Mn/Os−O/(×4 Å) 1.9486(9)∠Mn/Os−O−Cu (deg) 110.15(7)∠Mn/Os−O−Mn/Os (deg) 139.30(15)BVS(Cu) 2.37Rwp (%) 4.53Rp (%) 2.59

aSpace group Im3. Atomic sites: Ca 2a (0, 0, 0), Cu 6b (0, 0.5, 0.5),Mn/Os 8c (0.25, 0.25, 0.25), O 24g (0, y, z). The BVS values (Vi)were calculated using the formula Vi = ∑jSij, where Sij = exp[(r0 −rij)/0.37)]. The r0 value of Cu2+ is 1.679 Å.

Figure 3. XAS of (a) Cu L2,3-edges, (b) Mn L2,3-edges, and (c) Os L3-edges of CCMOO. The dashed line in part b shows a simplesuperposition of LaMnO3 and Sr3Mn2O7 at a 1:1 ratio. The XASspectra of some related references are also shown for comparison.

Figure 4. (a) Temperature-dependent magnetic susceptibilitymeasured at 0.1 and 1 T with ZFC and FC modes for CCMOO.(b) Field-dependent magnetization measured at different temper-atures.

Inorganic Chemistry Article

DOI: 10.1021/acs.inorgchem.9b02576Inorg. Chem. 2019, 58, 15529−15535

15531

become constant. Figure 4b presents the field-dependentmagnetization of CCMOO at selected temperatures. Below TC,e.g., at 2 and 200 K, the magnetization drastically increaseswith increasing field, and nearly becomes saturated at 1 T. Thesaturated moment observed at 2 K and 7 T is 7.8 μB/formulaunits (f.u.), indicating a large ferromagnetic component. Thecoercive field detected at 2 K is only about 900 Oe. Thesefeatures reveal the soft ferromagnetic behavior of CCMOO.Usually, the B-site-disordered perovskites show nonmagneticor lower spin-ordering temperatures in 3d−5d-hybridizedsystems. For instance, no magnetic phase transition is observedin the B-site-disordered CaCu3(Cu2Ir2)O12−δ

21 and Ca-Cu3Fe2Nb2O12.

22 In the B-site-disordered CaCu3Mn2Ir2O12, aspin glass transition instead of a long-range spin ordering isfound to occur at a lower temperature of about 50 K.20 Incomparison, the current CCMOO possesses a higher TC nearroom temperature and a large saturated moment up to 7.8 μB/f.u., although the B-site Mn 3d and Os 5d ions are alsodistributed disorderly.To gain deeper insight into the spin coupling for CCMOO,

the XMCD spectra were measured. This element-selectivemethod, on the one hand, can provide information of spinarrangement between any two magnetic elements in acompound; on the other hand, one can calculate the spinmagnetic moment (mspin) and orbital magnetic moment (morb)on the basis of the XMCD data.35−37 Figure 5 shows the

obtained XMCD spectra. At first glance, one can find that theXMCD signals for the Cu and Mn ions possess the same sign,opposite to the XMCD signal of Os, indicating a ferrimagneticCu2+(↑)Mn3.5+(↑)Os4.5+(↓) spin configuration. Similar spincoupling was reported in the A- and B-site-ordered quadrupleperovskite CaCu3Fe2Os2O12, in which the stronger Cu(↑)−Os(↓) and Fe(↑)−Os(↓) antiferromagnetic interactions over-come the weaker Cu(↑)−Fe(↓) one and thus lead to theferrimagnetic Cu(↑)−Fe(↑)−Os(↓) spin configuration.38

Furthermore, the spin and orbital moments can be obtainedby the so-called sum rule calculations proposed by Thole etal.37 and Carra et al.35 with the formulas

∫

∫

∫ ∫

∫

μ μ

μ μ

μ μ μ μ

μ μ

= −−

+× −

+ ⟨ ⟩

= −− − −

+

× −

++ −

++ −

+ −+

+ −

++ −

mE

En

m TE E

E

n

4 ( ) d

3 ( ) d(10 )

76 ( ) d 4 ( ) d

( ) d

(10 )

z

orbL L

L L

d

spin

L L L

L L

d

3 2

3 2

3 3 2

3 2

Here nd is the electrons occupying the d orbitals in a transitionmetal, μ+ (μ−) is the XAS spectrum with the magnetic fieldparallel (antiparallel) to the spin of the incident light, and L3and L2 indicate the integrated region. The term ⟨Tz⟩ is theintraatomic dipole moment, which increases with an enhance-ment of the local distortion and is negligible for the cubic localsymmetry. In CCMOO, the single Mn/OsO6 octahedron isrigid, indicating a negligible value of ⟨Tz⟩.

39,40 The spin andorbital moments for Cu2+ and Os4.5+ obtained by the sum rulecalculation are listed in Table 2. For an Os4.5+ state mixed with

Os4+ and Os5+, the strong spin−orbital effect makes Os4+

nonmagnetic, while Os5+ is magnetic. In comparison, the totalmagnetic moment for each Cu2+ (0.65 μB) is much larger thanthat of Os4.5+ (−0.049 μB). Note that, for the transition metalMn, the sum rule calculation is not physically sensible becauseof the significant overlap between Mn L3- and Mn L2-edges.39,41,42 To obtain a correct spin moment fromexperimental Mn L2,3 XMCD spectra, we performed full-atomic-multiplet ligand-field calculations using the XTLS 9.0code.43 The related parameters we used are reported in ref 44.Considering the mixed valence of Mn3.5+, we separatelycalculated Mn3+ and Mn4+. The calculated μ+, μ−, andXMCD spectra are presented in Figure 5d. Our calculationswell reproduce the experimental results (Figure. 5c), yieldingan average moment mspin = 3.47 μB per Mn ion in CCMOO.The total moment obtained from the XMCD measurement isabout 8.8 μB/f.u., which is close to the value obtained from themagnetization measurement.Figure 6 shows the temperature dependence of the resistivity

measured at 0 and 6 T for CCMOO. With decreasing

Figure 5. XMCD spectra of CCMOO for (a) Cu L2,3-edges, (b) OsL2,3-edges, and (c) Mn L2,3-edges. (d) Mn L2,3-edges for theoreticalcalculation. The photon spin is aligned parallel (μ+, black line) andantiparallel (μ−, red line) to the applied magnetic field. The XMCDspectra (μ+ − μ−) are shown in blue. The dotted line stands for thebackground.

Table 2. Spin Moment (mspin), Orbital Moment (morb), andTotal Moment (mtot) for Cu

2+ and Os4.5+ Obtained by theXMCD Sum Rule Calculations of CCMOO

mspin (μB) morb (μB) mtot (μB)

Cu2+ 0.57 0.08 0.65Os4.5+ −0.05 0.001 −0.049

Figure 6. Temperature dependence of the resistivity measured at 0and 6 T as well as the MR curve between them for CCMOO.

Inorganic Chemistry Article

DOI: 10.1021/acs.inorgchem.9b02576Inorg. Chem. 2019, 58, 15529−15535

15532

temperature, the zero-field resistivity slightly increases from 6.6mΩ·cm at 380 K to 24.0 mΩ·cm at 2 K. Although there is along-range ferrimagnetic phase transition at 280 K, theresistivity looks smoothly changed without any anomalyoccurring around the critical temperature, indicating negligiblemagnetoelectric coupling. This is reminiscent of the isostruc-tural CaCu3Mn4O12, where although a large low-field MRbehavior is found to occur, there is no resistivity anomaly nearthe spin-ordering temperature.45 In comparison, the temper-ature-dependent resistivity of CCMOO measured under a 6 Tfield is similar to that measured at 0 T, but the magnitude isreduced lightly below TC, suggesting a negative MR behavior.When the MR values between these two fields are calculatedusing the function MR = 100% × [ρ(6 T) − ρ(0 T)]/ρ(0 T),one can find a clear kink at TC. Because the magnetic domainstend to be aligned along the direction of the applied magneticfield, the domain wall scattering is reduced under a higher field.As a result, CCMOO exhibits negative MR behavior and themagnitude of MR gradually decreases upon cooling below TC(see Figure 6). As is well-known, the MR of CaCu3Mn4O12 isas large as 40% at 20 K and 5 T.45 However, the MR valuesbetween 0 and 6 T are less than 4% in the whole temperatureregion of 2−380 K for CCMOO. Therefore, the introductionof Os into the B site significantly reduces the MR effect. This isdifferent from the simple ABO3 manganese perovskite, wherethe formation of a mixed Mn charge state favors the MReffect.46 Note that the resistivity of CCMOO is measured on apolycrystalline pellet, in which grain boundaries play a role inelectrical transport. Considering the small resistivity values aswell as the weak temperature dependence, the intrinsic electricconductivity of CCMOO most probably would be metallic, asexpected from the mixed and disordered Mn3.5+ and Os4.5+ ionsat the B site, which dominate the electrical transport behaviorby corner-sharing Mn/OsO6 octahedra.To further understand the magnetic and transport properties

of CCMOO, the heat capacity (CP) as a function of thetemperature was measured in 2−350 K. As shown in Figure 7a,CP displays a broadening anomaly around TC. This may imply

the formation of some short-range ferrimagnetic correlationsabove TC, so that a portion of the magnetic entropy is released.Below 10 K, the CP data can be well fitted using the formula CP= γT + αT3 + βT3/2 (Figure 7b), where the γT, αT3, and βT3/2

terms describe the electron, lattice, and ferromagneticexcitation contributions to the total heat capacity, respectively.The fitting gives the coefficient γ = 0.0216 J/mol·K2, α = 3.62× 10−4 J/mol·K4, and β = 0.0204 J/mol·K5/2. By comparison,the values of γ and β are larger than that of α by 2 orders ofmagnitude. One thus infers that the electron and magnetoncontributions dominate the low-temperature heat capacity ofCCMOO, in agreement with the metallic electronic behaviordiscussed above as well as the long-range ferrimagneticordering with a high TC and a large saturated magneticmoment.

4. CONCLUSIONSIn summary, a new 3d−5d-hybridized oxide, CCMOO, wasprepared at 5 GPa and 1473 K. Rietveld analysis and SAEDreveal that the compound crystallizes into an A-site-orderedbut B-site-disordered quadruple perovskite structure withspace group Im3. XAS shows that the charge states oftransition metals are Cu2+/Mn3.5+/Os4.5+. Different from thelower spin-ordering temperatures or even nonmagneticbehaviors observed in most B-site-disordered perovskites, thecurrent CCMOO exhibits a near-room-temperature ferrimag-netic ordering with a high TC of 280 K, due to Cu2+(↑)-Mn3.5+(↑)Os4.5+(↓) spin coupling, as revealed by XMCDmeasurement. On the basis of the magnetization measurement,a large saturated magnetic moment (7.8 μB/f.u.) is found tooccur in CCMOO, in agreement with the XMCD sum rulecalculations. Although the temperature dependence of theresistivity does not show any visible anomaly, an apparent kinkis observed in the magnetoresistance curve at TC. In addition, abroadening anomaly is also found around TC in specific heat.The low-temperature fitting of specific heat indicates metallicelectrical transport behavior of CCMOO, as expected from theB-site-disordered structure as well as the mixed Mn3.5+ andOs4.5+ charge states. This work provides a rare 3d−5d-hybridized disordered perovskite system with an unusuallyhigh long-range spin-ordering temperature as well as a largemagnetic moment.

■ AUTHOR INFORMATIONCorresponding Author*E-mail: ywlong@iphy.ac.cn.ORCIDYouwen Long: 0000-0002-8587-7818FundingThis work was supported by the National Key R&D Programof China (Grants 2018YFE0103200 and 2018YFA0305700),the National Natural Science Foundation of China (Grants11934017, 51772324, and 11574378), and the ChineseAcademy of Sciences (Grants QYZDB-SSW-SLH013,GJHZ1773, and YZ201555). The research in Dresden waspartially supported by the DFG through SFB 1143.NotesThe authors declare no competing financial interest.

■ ACKNOWLEDGMENTSThe authors thank Yunyu Yin and Hongshan Deng for theiruseful discussion.

Figure 7. (a) Specific heat as a function of the temperature forCCMOO. (b) Low-temperature fitting of the specific heat using thefunction CP = γT + αT3 + βT3/2 below 10 K. The circles representexperimental data, and the red curve is the fitting result.

Inorganic Chemistry Article

DOI: 10.1021/acs.inorgchem.9b02576Inorg. Chem. 2019, 58, 15529−15535

15533

■ REFERENCES(1) Li, H.; Lv, S.; Han, D.; Liu, X.; Meng, J. Ferromagneticinteraction between A-site Cu spins in A-site ordered perovskitesA′Cu3Sn4O12 with A′=Ca2+, Sr2+, Pb2+, and La3+. Chem. Phys. Lett.2010, 494, 213−217.(2) Munoz, A.; Martínez-Lope, M. J.; Retuerto, M.; Falcon, H.;Alonso, J. A. Ferromagnetic behavior in La(Cu3‑xMnx)Mn4O12 (x =1,2) perovskites. J. Appl. Phys. 2008, 104, 083911.(3) Wang, X.; Chai, Y.; Zhou, L.; Cao, H.; Cruz, C. D.; Yang, J.; Dai,J.; Yin, Y.; Yuan, Z.; Zhang, S.; Yu, R.; Azuma, M.; Shimakawa, Y.;Zhang, H.; Dong, S.; Sun, Y.; Jin, C.; Long, Y. Observation ofMagnetoelectric Multiferroicity in a Cubic Perovskite System:LaMn3Cr4O12. Phys. Rev. Lett. 2015, 115, 087601.(4) Zhou, L.; Dai, J.; Chai, Y.; Zhang, H.; Dong, S.; Cao, H.; Calder,S.; Yin, Y.; Wang, X.; Shen, X.; Liu, Z.; Saito, T.; Shimakawa, Y.;Hojo, H.; Ikuhara, Y.; Azuma, M.; Hu, Z.; Sun, Y.; Jin, C.; Long, Y.Realization of Large Electric Polarization and Strong MagnetoelectricCoupling in BiMn3Cr4O12. Adv. Mater. 2017, 29, 1703435.(5) Lee, P. A.; Nagaosa, N.; Wen, X.-G. Doping a Mott insulator:Physics of high-temperature superconductivity. Rev. Mod. Phys. 2006,78, 17−85.(6) Park, J. H.; Vescovo, E.; Kim, H. J.; Kwon, C.; Ramesh, R.;Venkatesan, T. Magnetic properties at surface boundary of a half-metallic ferromagnet La0.7Sr0.3MnO3. Phys. Rev. Lett. 1998, 81, 1953−1956.(7) Viola, G.; Verbylo, D.; Orlovskaya, N.; Reece, M. J. Effect ofcomposition on rate dependence of ferroelastic/ferroelectric switchingin perovskite ceramics. Mater. Sci. Technol. 2009, 25, 1312−1315.(8) King, G.; Woodward, P. M. Cation ordering in perovskites. J.Mater. Chem. 2010, 20, 5785−5796.(9) Witczak-Krempa, W.; Chen, G.; Kim, Y. B.; Balents, L.Correlated Quantum Phenomena in the Strong Spin-Orbit Regime.Annu. Rev. Condens. Matter Phys. 2014, 5, 57−82.(10) Vasala, S.; Karppinen, M. A2B′B″O6 perovskites: A review. Prog.Solid State Chem. 2015, 43, 1−36.(11) Zhang, J.; Ji, W. J.; Xu, J.; Geng, X. Y.; Zhou, J.; Gu, Z. B.; Yao,S. H.; Zhang, S. T. Giant positive magnetoresistance in half-metallicdouble-perovskite Sr2CrWO6 thin films. Sci. Adv. 2017, 3, e1701473.(12) Kato, H.; Okuda, T.; Okimoto, Y.; Tomioka, Y.; Takenoya, Y.;Ohkubo, A.; Kawasaki, M.; Tokura, Y. Metallic ordered double-perovskite Sr2CrReO6 with maximal Curie temperature of 635 K.Appl. Phys. Lett. 2002, 81, 328−330.(13) Krockenberger, Y.; Mogare, K.; Reehuis, M.; Tovar, M.; Jansen,M.; Vaitheeswaran, G.; Kanchana, V.; Bultmark, F.; Delin, A.;Wilhelm, F.; Rogalev, A.; Winkler, A.; Alff, L. Sr2CrOsO6: End pointof a spin-polarized metal-insulator transition by 5d band filling. Phys.Rev. B: Condens. Matter Mater. Phys. 2007, 75, 020404.(14) Long, Y. A-site ordered quadruple perovskite oxides. Chin. Phys.B 2016, 25, 078108.(15) Chen, W. T.; Mizumaki, M.; Seki, H.; Senn, M. S.; Saito, T.;Kan, D.; Attfield, J. P.; Shimakawa, Y. A half-metallic A- and B-site-ordered quadruple perovskite oxide CaCu3Fe2Re2O12 with largemagnetization and a high transition temperature. Nat. Commun. 2014,5, 3909.(16) Long, Y. W.; Hayashi, N.; Saito, T.; Azuma, M.; Muranaka, S.;Shimakawa, Y. Temperature-induced A-B intersite charge transfer inan A-site-ordered LaCu3Fe4O12 perovskite. Nature 2009, 458, 60−63.(17) Li, H.; Lv, S.; Wang, Z.; Xia, Y.; Bai, Y.; Liu, X.; Meng, J.Mechanism of A-B intersite charge transfer and negative thermalexpansion in A-site-ordered perovskite LaCu3Fe4O12. J. Appl. Phys.2012, 111 (10), 103718.(18) Mizumaki, M.; Chen, W. T.; Saito, T.; Yamada, I.; Attfield, J.P.; Shimakawa, Y. Direct observation of the ferrimagnetic coupling ofA-site Cu and B-site Fe spins in charge-disproportionatedCaCu3Fe4O12. Phys. Rev. B: Condens. Matter Mater. Phys. 2011, 84(9), 094418.(19) Yamada, I.; Marukawa, S.; Murakami, M.; Mori, S. “True”negative thermal expansion in Mn-doped LaCu3Fe4O12 perovskiteoxides. Appl. Phys. Lett. 2014, 105 (23), 231906.

(20) Ye, X.; Liu, Z.; Wang, W.; Hu, Z.; Lin, H.-J.; Weng, S.-C.;Chen, C.-T.; Yu, R.; Tjeng, L.-H.; Long, Y. High-pressure synthesisand spin glass behavior of a Mn/Ir disordered quadruple perovskiteCaCu3Mn2Ir2O12. J. Phys.: Condens. Matter 2019 DOI: 10.1088/1361-648X/ab5386(21) Zhao, Q.; Yin, Y.-Y.; Dai, J.-H.; Shen, X.; Hu, Z.-W.; Yang, J.-Y.;Wang, Q.-T.; Yu, R.-C.; Li, X.-D.; Long, Y.-W. A-site orderedperovskite CaCu3Cu2Ir2O12‑δ with square-planar and octahedralcoordinated Cu ions. Chin. Phys. B 2016, 25, 020701.(22) Senn, M. S.; Chen, W.-t.; Saito, T.; García-Martín, S.; Attfield,J. P.; Shimakawa, Y. B-Cation Order Control of Magnetism in the1322 Perovskite CaCu3Fe2Nb2O12. Chem. Mater. 2014, 26, 4832−4837.(23) Rietveld, H. M. The Rietveld method. Phys. Scr. 2014, 89,098002.(24) Chenavas, J.; Joubert, J. C.; Marezio, M.; Bochu, B. Synthesisand Crystal-Structure of CaCu3Mn4O12: A New Ferromagnetic-Perovskite-Like Compound. J. Solid State Chem. 1975, 14, 25−32.(25) Brown, I. D.; Altermatt, D. Bond-Valence Parameters Obtainedfrom a Systematic Analysis of the Inorganic Crystal-StructureDatabase. Acta Crystallogr., Sect. B: Struct. Sci. 1985, 41, 244−247.(26) Pantic, J.; Urbanovich, V.; Poharc-Logar, V.; Jokic, B.;Stojmenovic, M.; Kremenovic, A.; Matovic, B. Synthesis andcharacterization of high-pressure and high-temperature sphene(CaTiSiO5). Phys. Chem. Miner. 2014, 41, 775−782.(27) Rehr, J. J.; Mustre de Leon, J.; Zabinsky, S. I.; Albers, R. C.Theoretical X-Ray Absorption Fine-Structure Standards. J. Am. Chem.Soc. 1991, 113, 5135−5140.(28) Hollmann, N.; Hu, Z.; Maignan, A.; Gunther, A.; Jang, L. Y.;Tanaka, A.; Lin, H. J.; Chen, C. T.; Thalmeier, P.; Tjeng, L. H.Correlation effects in CaCu3Ru4O12. Phys. Rev. B: Condens. MatterMater. Phys. 2013, 87, 155122.(29) Mitra, C.; Hu, Z.; Raychaudhuri, P.; Wirth, S.; Csiszar, S. I.;Hsieh, H. H.; Lin, H. J.; Chen, C. T.; Tjeng, L. H. Direct observationof electron doping in La0.7Ce0.3MnO3 using X-ray absorptionspectroscopy. Phys. Rev. B: Condens. Matter Mater. Phys. 2003, 67,092404.(30) Burnus, T.; Hu, Z.; Hsieh, H. H.; Joly, V. L. J.; Joy, P. A.;Haverkort, M. W.; Wu, H.; Tanaka, A.; Lin, H. J.; Chen, C. T.; Tjeng,L. H. Local electronic structure and magnetic properties ofLaMn0.5Co0.5O3 studied by X-ray absorption and magnetic circulardichroism spectroscopy. Phys. Rev. B: Condens. Matter Mater. Phys.2008, 77, 125124.(31) Lacroix, C. Crystallographic and Magnetic Structures ofMaterials with Threefold Orbital Degeneracy: Application toCaCu3Ti4O12. J. Phys. C: Solid State Phys. 1980, 13, 5125−5136.(32) Hossain, M. A.; Hu, Z.; Haverkort, M. W.; Burnus, T.; Chang,C. F.; Klein, S.; Denlinger, J. D.; Lin, H. J.; Chen, C. T.; Mathieu, R.;Kaneko, Y.; Tokura, Y.; Satow, S.; Yoshida, Y.; Takagi, H.; Tanaka, A.;Elfimov, I. S.; Sawatzky, G. A.; Tjeng, L. H.; Damascelli, A. Crystal-field level inversion in lightly Mn-doped Sr3Ru2O7. Phys. Rev. Lett.2008, 101, 016404.(33) Mitchell, J. F.; Millburn, J. E.; Medarde, M.; Short, S.;Jorgensen, J. D.; Fernandez-Diaz, M. T. Sr3Mn2O7: Mn4+ parentcompound of the n = 2 layered CMR manganites. J. Solid State Chem.1998, 141, 599−603.(34) Adler, P.; Ksenofontov, V.; Paul, A. K.; Reehuis, M.; Yan, B.;Jansen, M.; Felser, C. Magnetic phase transitions and iron valence inthe double perovskite Sr2FeOsO6. Hyperfine Interact. 2014, 226, 289−297.(35) Carra, P.; Thole, B. T.; Altarelli, M.; Wang, X. X-ray circulardichroism and local magnetic fields. Phys. Rev. Lett. 1993, 70, 694−697.(36) Stohr, J.; Nakajima, R. Magnetic properties of transition metalmultilayers studied with X-ray magnetic circular dichroism spectros-copy. IBM J. Res. Dev. 1998, 42, 73−88.(37) Thole, B. T.; Carra, P.; Sette, F.; van der Laan, G. X-ray circulardichroism as a probe of orbital magnetization. Phys. Rev. Lett. 1992,68, 1943−1946.

Inorganic Chemistry Article

DOI: 10.1021/acs.inorgchem.9b02576Inorg. Chem. 2019, 58, 15529−15535

15534

(38) Deng, H.; Liu, M.; Dai, J.; Hu, Z.; Kuo, C.; Yin, Y.; Yang, J.;Wang, X.; Zhao, Q.; Xu, Y.; Fu, Z.; Cai, J.; Guo, H.; Jin, K.; Pi, T.;Soo, Y.; Zhou, G.; Cheng, J.; Chen, K.; Ohresser, P.; Yang, Y.-f.; Jin,C.; Tjeng, L.-H.; Long, Y. Strong enhancement of spin ordering by A-site magnetic ions in the ferrimagnet CaCu3Fe2Os2O12. Phys. Rev. B:Condens. Matter Mater. Phys. 2016, 94, 024414.(39) Teramura, Y.; Tanaka, A.; Jo, T. Effect of Coulomb interactionon the X-ray magnetic circular dichroism spin sum rule in 3dtransition elements. J. Phys. Soc. Jpn. 1996, 65, 1053−1055.(40) Agrestini, S.; Chen, K.; Kuo, C. Y.; Zhao, L.; Lin, H. J.; Chen,C. T.; Rogalev, A.; Ohresser, P.; Chan, T. S.; Weng, S. C.;Auffermann, G.; Volzke, A.; Komarek, A. C.; Yamaura, K.;Haverkort, M. W.; Hu, Z.; Tjeng, L. H. Nature of the magnetismof iridium in the double perovskite Sr2CoIrO6. Phys. Rev. B: Condens.Matter Mater. Phys. 2019, 100, 014443.(41) van der Laan, G.; Moore, K. T.; Tobin, J. G.; Chung, B. W.;Wall, M. A.; Schwartz, A. J. Applicability of the spin-orbit sum rule forthe actinide 5f states. Phys. Rev. Lett. 2004, 93, 097401.(42) Piamonteze, C.; Miedema, P.; de Groot, F. M. F. Accuracy ofthe spin sum rule in XMCD for the transition-metall edges frommanganese to copper. Phys. Rev. B: Condens. Matter Mater. Phys. 2009,80, 184410.(43) Tanaka, A.; Jo, T. Resonant 3d, 3p and 3s Photoemission inTransition-Metal Oxides Predicted at 2p Threshold. J. Phys. Soc. Jpn.1994, 63, 2788−2807.(44) Parameters used in cluster calculations (eV). For the Co3+ ion:Udd = 4.5, Ucd = 6.0, Δ = 5.5, 10Dq = 0.55, V(xy) = −3.66, V(yz)V(zx) = −2.87, V(x2−y2) = 2.44, V(3z2−r2) = 1.35, and Slaterintegrals were set to 80% of the Hartree−Fock values. For the Mn4+

ion: Udd = 4.5, Ucd = 6.0, Δ = 1.0, 10Dq = 0.8, V(t2g) = 2.44, V(eg) =−3.66, and Slater integrals were set to 70% of the Hartree−Fockvalues.(45) Zeng, Z.; Greenblatt, M.; Subramanian, M. A.; Croft, M. Largelow-field magnetoresistance in perovskite-type CaCu3Mn4O12 withoutdouble exchange. Phys. Rev. Lett. 1999, 82, 3164−3167.(46) Jin, S.; Tiefel, T. H.; Mccormack, M.; Fastnacht, R. A.; Ramesh,R.; Chen, L. H. Thousandfold Change in Resistivity in Magneto-resistive La-Ca-Mn-O Films. Science 1994, 264, 413−415.

Inorganic Chemistry Article

DOI: 10.1021/acs.inorgchem.9b02576Inorg. Chem. 2019, 58, 15529−15535

15535