Structural and Magnetic Properties of ${\hbox {Tm}}_{2}{\hbox {CrFe}}_{16-x}{\hbox {Si}}_{x}$ Compounds

Hao Yanming,Qin Hongwei,Hu Jifan,Wu Yanzhao,Zhang Xuemin,Liang Feifei

doi:10.1109/tmag.2011.2146759

Abstract

The structural and magnetic properties of Tm 2 CrFe 16-x Si x ( x =0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0) compounds are investigated by means of X-ray diffraction and magnetization measurements. The results show that the Tm 2 CrFe 16-x Si x compounds are in a single phase with the hexagonal Th 2 Ni 17 -type structure. The lattice parameters a and c and the unit-cell volume v decrease monotonously with x increasing. The Curie temperature T C increases initially ( x <; 1.5) with x increasing, followed by a decrease at higher concentrations ( x >; 1.5) . There is a maximum of the Curie temperature, which is about 450 K, at x =1.5. Spin reorientations are observed in the temperature dependences of the magnetization of Tm 2 CrFe 16-x Si x compounds. The spin reorientation temperature ( T sr ) increases from 144 K at x =0 to 259 K at x =3.0 with x increasing. This means that the Si atoms substituting for Fe atoms can increase obviously the easy-axis magnetocrystalline anisotropy. The analysis shows that the effect of Cr substitution and the effect of Si substitution on the Curie temperature and the magnetocrystalline anisotropy of R 2 Fe 17 compound can be superposed.

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