Investigation Into Magnetic Anisotropy of Low-Temperature Phase MnBi Thin Films

The temperature dependence of magnetic anisotropy in the low-temperature phase MnBi thin films is discussed in conjunction with saturation magnetization and lattice constants. It is experimentally found that Ku is inversely proportional to the eighth power of the saturation magnetization Ms. It is also found that the Ku is proportional to the unit-cell volume. The calculation based on first principles of magnetic anisotropy energy as a function of lattice constants (a and c) and statistical simulations of its spin-temperature dependence is consistent with the experimental results. However, the spin-reorientation transition taking place at 100 K is not accounted for by the present calculation.