TY - JOUR
T1 - Twofold and fourfold symmetric anisotropic magnetoresistance effect in a model with crystal field
AU - Kokado, Satoshi
AU - Tsunoda, Masakiyo
N1 - Publisher Copyright:
© 2015 The Physical Society of Japan.
Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 2015/9/15
Y1 - 2015/9/15
N2 - We theoretically study the twofold and fourfold symmetric anisotropic magnetoresistance (AMR) effects of ferromagnets. We here use the two-current model for a system consisting of a conduction state and localized d states. The localized d states are obtained from a Hamiltonian with a spin-orbit interaction, an exchange field, and a crystal field. From the model, we first derive general expressions for the coefficient of the twofold symmetric term (C2) and that of the fourfold symmetric term (C4) in the AMR ratio. In the case of a strong ferromagnet, the dominant term in C2 is proportional to the difference in the partial densities of states (PDOSs) at the Fermi energy (EF) between the de and dγ states, and that in C4 is proportional to the difference in the PDOSs at EF among the de states. Using the dominant terms, we next analyze the experimental results for Fe4N, in which |C2| and |C4| increase with decreasing temperature. The experimental results can be reproduced by assuming that the tetragonal distortion increases with decreasing temperature.
AB - We theoretically study the twofold and fourfold symmetric anisotropic magnetoresistance (AMR) effects of ferromagnets. We here use the two-current model for a system consisting of a conduction state and localized d states. The localized d states are obtained from a Hamiltonian with a spin-orbit interaction, an exchange field, and a crystal field. From the model, we first derive general expressions for the coefficient of the twofold symmetric term (C2) and that of the fourfold symmetric term (C4) in the AMR ratio. In the case of a strong ferromagnet, the dominant term in C2 is proportional to the difference in the partial densities of states (PDOSs) at the Fermi energy (EF) between the de and dγ states, and that in C4 is proportional to the difference in the PDOSs at EF among the de states. Using the dominant terms, we next analyze the experimental results for Fe4N, in which |C2| and |C4| increase with decreasing temperature. The experimental results can be reproduced by assuming that the tetragonal distortion increases with decreasing temperature.
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U2 - 10.7566/JPSJ.84.094710
DO - 10.7566/JPSJ.84.094710
M3 - Article
AN - SCOPUS:84941702226
VL - 84
JO - Journal of the Physical Society of Japan
JF - Journal of the Physical Society of Japan
SN - 0031-9015
IS - 9
M1 - 094710
ER -