On the Magnetic Anisotropy of Single Crystal of Mn₅Ge₃

Abstract

The magnetic anisotropy of a single crystal of Mn₅Ge₃ is measured by means of a torque magnetometer. The direction of easy magnetization is found to lie along the c-axis between room and liquid nitrogen temperatures. The anisotropy constants are determined as 3.0×10⁵ erg/cm³ at room temperature and 4.2×10⁶ erg/cm³ at liquid nitrogen temperature. The anisotropy constant determined from magnetization curves at liquid nitrogen temperature is 3.5×10⁶ erg/cm³, and agrees well with that from torque measurements. Calculation shows that magnetic dipolar interaction accounts for about 20% of the observed value of the anisotropy. Temperature dependence of the dipolar anisotropy is discussed using molecular field approximation.