Influence of the magnetic anisotropy dispersion in Ge$_{3}$Mn$_{5}$ clusters on the temperature dependences of magnetization in thin Ge:Mn films

The temperature dependences of magnetization M ( T ) of thin ion-implanted Ge:Mn (4 at % Mn) films containing Ge$_{3}$Mn$_{5}$ clusters were measured on samples cooled in the absence of magnetic field (zero field cooled, ZFC) and in a magnetic field of 10 kOe (field-cooled, FC). It has been established that the shape of ZFC–FC differential $M (T)$ curves is determined by lognormal distribution of the size-dependent magnetic anisotropy energy of Ge$_{3}$Mn$_{5}$ clusters. Analysis of the observed ZFC–FC magnetization curves allowed the magnetic anisotropy dispersion (variance) and magnetic anisotropy constant to be estimated.