Temperature dependence of magnetocrystalline anisotropy constants in the single variant state of L10-type FePt bulk single crystal

The temperature dependence of magnetocrystalline anisotropy constants and the saturation magnetization in a single variant state have been investigated for L1(0)-type Fe60Pt40 bulk single crystal prepared under compressive stress. The uniaxial magnetocrystalline anisotropy constant K-u evaluated from the magnetization curve is 6.9x10(7) erg cm(-3) at 5 K. The values of the second- and fourth-order magnetocrystalline anisotropy constants K-1 and K-2 at 5 K determined by the Sucksmith-Thompson method are 7.4 and 0.13x10(7) erg cm(-3), respectively. Both the values of K-u and K-1 decrease with increasing temperature T, while K-2 is almost independent of T. The difference between the power law of the Callen and Callen model is described by the dimensionality and the thermal variation of the axial ratio c/a due to the thermal expansion. (c) 2006 American Institute of Physics.