anomalous local transport in microfabricatedsr 2 ruo 4 -ru eutectic junction
Post on 05-Feb-2016
31 Views
Preview:
DESCRIPTION
TRANSCRIPT
-
Anomalous Local Transport in MicrofabricatedSr2RuO4-Ru Eutectic Junction
2009. 9. 4 NDSN2009@Nagoya Univ.AISTHiroshi KambaraSatoshi Kashiwaya
Tokyo Univ of Sci. Hiroshi YaguchiHokkaido Univ.Yasuhiro AsanoNagoya Univ.Yukio TanakaKyoto Univ.Yoshiteru Maeno
-
IntroductionHow is the local transport property?
If chiral domain exists, how is the transport property affected?Sr2RuO4 (Tc=1.5 K)
Chiral p-wave superconductor(spin-triplet pairing)Measurement of local transport characteristics of Sr2RuO4-Ru eutectic junction made by microfabrication.Observation of anomalous hysteresis in V-I
-
Sr2RuO4-Ru eutectic system ~3-K phase superconductivity~Sr2RuO4 Ru eutecticsMaeno et al., PRL 81, 3765 (1998).p-wave superconducting junction is naturally formed.
-
Extract a channel of Sr2RuO4-Ru junctionFocusing on the local superconducting channelby controlling the number of Ru-inclusionsKink structures appearafter FIB milling becauseonly a few channels are left.If microbridge is thin and narrow enough.
-
dV/dI-I characteristics Model of Josephson junctions in seriesTTc00Each channelS-S-SS-N-SIc0Ic1Ic2
-
Parity of the 3-K phasespsss0p03-K phase is also p-wave.( 1.5-K phase is p-wave.)ss00Monotonic increase of IcT > Tc0T < Tc0
-
Sample configuration (I // ab and I // c)
-
Anomalous hysteresis is observed for both I//ab and I//c direction.V-I & dV/dI-I characteristics (Anomalous hysteresis) I // ab
-
How are V-I characteristics anomalous?Anomalous features Voltage decreases at Isw. It switches to a lower Rn (normal resistance) branch with larger Ic.
(3) Opposite hysteresis loop compared to typical Josephson junction (JJ) s.Sr2RuO4-Ru
-
Magnetic field effectcf) Hc1(0) 70 G (1.5-K phase) Deguchi, Mao, Maeno, JPSJ(2004). sample 1 NO influence of vortices !FCZFCNo change in the hysteresis between FC and ZFC.H // c
-
Possible origin of the hysteresis
-
Possible origin of the anomalous hysteresisdomain wall motion variation of cross section variation of IcRupx+ipypx-ipyRuinitial stateIcIcSfilament (parallel domain) NO hysteresis
IcSDW (antiparallel domain) Hysteresis!(a) Inhomogeneous channel model
-
Possible origin of the anomalous hysteresis (b) 3-K phase+1.5-K phase coexistence model (kx or ky) (kxiky)(3) I = Isw Ic largerAssuming 3-K phase symmetry (kx) along the edge because of broken translational symmetry.
-
Questions for the chiral domain model
-
Summary of the anomalous hysteresis HysteresisInhomogeneous channelModel3-K + 1.5-K(kx) (kx+iky)VortexI // abI // c?No-magnetic field effectOK!probably OK?questioncontrarytotalMultiple switchChiral domainVortex origin is ruled out.
-
Local transport measurements have been done (I//ab, I//c) for Sr2RuO4-Ru eutectic samples made by FIB process. p-wave Josephson junctions are formed (3-K / 1.5-K / 3-K).
Anomalous hysteresis was observed for both current directions. (voltage drop, opposite hysteresis loop) Chiral domain is a possible origin with (a) Inhomogeneous channel model or (b) 3-K phase+1.5-K phase model or others?
Summary
**
top related