LOW TEMPERATURE MAGNETIC PROPERTIES OF AMORPHOUS Sm-Fe AND Sm-Co THIN FILMS

Abstract

The low temperature magnetic properties of the amorphous Sm-Fe and Sm-Co thin films are investigated. It is found that there exists a distribution of the orientation of the Fe atomic moment in the Sm-Fe films, and the compositional dependence of the effective magnetic moments of the Co atoms in the Sm-Co films is very similar to that of the amorphous Nd-Co films. The magnetic structures of these two alloy systems are determined: there are asperomagnetic structure for the Sm-Fe thin films and the collinear ferromagnetic structure for the Sm-Co thin films. The magnetic moment of Sm atoms is very close to zero. The strength, temperature and compositional dependences of coercivity for these two amorphous alloy systems are measured. The Hc of Sm-Fe films is much larger than that of Sm-Co films, For the Sm-Fe amorphous films, Hc increases very quickly with increasing of the contants of samarium, and severely drops with increasing of temperature in the very low temperature region. But for the Sm-Co amorphous films, Hc reaches a maximum at about 43 at% Sm, and decreases with increasing of temperature in the exponental form. It is also found that the temperature dependence of magnetization in the low temperature region may be caused by the Bloch spin-wave excitation and Stoner electric excitation simultaneously.