Magnetic torque measurements on NiO (111) platelets

Abstract
Magnetic anisotropy within the easy plane (111) is investigated by torque measurements on NiO platelets which can be made fully free of antiferromagnetic domain walls. The anisotropy constant K2 and the critical field for spin flopping Hc are determined in a temperature range from 288K to the Neel point, 523K. The difference of the perpendicular and parallel susceptibilities Delta chi = chi perpendicular to - chi /sub /// is also determined at temperatures from 77 to 523 K, using the magnetic torque measurements. At room temperatures (305K), K2 is found to be 44 erg g-1, and Hc amounts to 16.0 kOe, in agreement with the results of the proceeding optical observations. The susceptibility data indicate that the temperature-independent perpendicular susceptibility chi perpendicular to is 9.1*10-6 emu g-1.