Classical Theory of the Temperature Dependence of Magnetic Anisotropy Energy
Abstract
The consequences are analyzed of the following two assumptions: (1) the effect of temperature upon magnetic anisotropy arises solely from the introduction of local deviations in the direction of magnetization; and (2) the local deviation in an elementary region is the resultant of a very large number of independent deviations. The influence of these local deviations upon the magnetic anisotropy is most conveniently expressed by representing the magnetic energy as a series of surface harmonics. The coefficient of the nth harmonic is found to vary with temperature as {J_{s}(T)J_{s}(0)} raised to the power n(n+1)2. The first two exponents for cubic crystals have values of 10 and 21, respectively. The exponent 10 expresses almost precisely the observed temperature dependence of K_{1} in iron. In nickel the anisotropy decreases much more rapidly than predicted. It is deduced that the above two assumptions are applicable to iron but not to nickel.
 Publication:

Physical Review
 Pub Date:
 December 1954
 DOI:
 10.1103/PhysRev.96.1335
 Bibcode:
 1954PhRv...96.1335Z