Use of rotational transverse magnetometry to measure anisotropy energy

Rotational transverse magnetometry (RTM) is used to measure the anisotropy field of magnetic thin films. Magnetization reversal during rotation of a two-dimensional isotropic sample in an applied field is discussed. The relation between the transverse magnetization M-y and the applied field H is solved numerically. An excellent approximation for the transverse magnetization is M-y/M-s = A(1-H/H-k)(2.5), where A = 1.1434, and H-k is the anisotropy field. For curve fitting to experimental data, both A and H-k were used as fitting parameters. Comparison between a constructed torque hysteresis method and this vibrating sample magnetometer (VSM) RTM method is made theoretically and experimentally. Both results show that the VSM RTM will give a good extrapolation of the anisotropy field, whereas the torque measurement will slightly overestimate it. Anisotropy energy is calculated based on the anisotropy field and saturation magnetization for magnetic thin films. (C) 1999 American Institute of Physics. [S0021-8979(99)29508-4].