Accuracy of 45° torque method for obtaining anisotropy constant of 2D random films

Computer simulation was used to examine the accuracy of anisotropy energy constant, K₂ of thin film media obtained from the 45° torque method. The easy axes of the media were distributed randomly in plane. The obtained K_u value depends on range of the applied field. For 2D random media with H_K=1-40 kOe, M _s=100-600 emu/cm³, A=0-1×10^-6 erg/cm, separation between adjacent grains=0-a nm, the difference between obtained K_u value and exact K_u was at most 20%, if the range of applied field was larger than 10-20 kOe. Here, the standard values of the physical parameters were H_K=10 kOe, M _s=460 emu/cma, A=0, separation between adjacent grains=0, and each parameter was varied successively