modelo de stoner para o ferromagnetismo metálico · edge of the d-band of majority spin electrons...
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Modelo de Stoner para o Ferromagnetismo metálico
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Modelo de Stoner: Dependência com a Temperatura
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Lei de Curie-Weiss
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Magnetismo Localizado (Modelo de Heisenberg)
Interação de Troca
Acoplamento dipolar com campo externo
Hamiltoniano não linear → difícil diagonalização
Aproximação de campo médio:
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Para um material ferromagnético, todos os spins têm valores médios idênticos:
Além disso:
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Solução é equivalente ao caso de magnetismo metálico !!
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Lei de Curie-Weiss (de novo !)
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Antiferromagnetismo
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Através de um tratamento similar ao caso ferromagnético:
M+ → 0 para
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Para T > TN:
Lei de Curie-Weiss (de novo !)
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Ondas de Spin
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Magnetização de uma amostra ferromagnética