Finite-temperature anisotropy of magnetic alloys

Authors

Ralph Skomski, University of Nebraska-LincolnFollow
O.N. Mryasov, University of Nebraska - Lincoln
J. Zhou, University of Nebraska - Lincoln
David J. Sellmyer, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

April 2006

Comments

Published by American Institute of Physics. J. Applied Physics 99, 08E916 (2006). ©2006 American Institute of Physics. Permission to use. http://jap.aip.org/jap/.

Abstract

The temperature dependence of the magnetic anisotropy of ferromagnetic materials is analyzed. Simple ferromagnets, such as Fe and Co, obey the m=n (n+1)/2 power laws predicted by the Callen and Callen [Phys. Rev. 129, 578 (1963)] theory, but in alloys, the applicability of the theory is an exception rather than the rule. Many alloys, such as the rare-earth transition-metal intermetallics and L1₀ magnets, violate a basic assumption of the theory, namely, that the single-ion anisotropy and the spontaneous magnetization have the same origin. This is the reason for significant deviations from the Callen and Callen behavior, such as the m=2 law we obtained for L1₀ alloys.