CRYSTAL STRUCTURE AND MAGNETIC PROPERTIES OF R(T,M)13 COMPOUNDS. Jingkui Liang, Guanghui Rao, Weihua Tang, Yanming Zhao, Yongquan Guo, Xiaohua Yan, Institute Of Physics, Chinese Academy Of Sciences, Beijing 100080, P.R. China
Rare earth (R) transition metal (T) intermetallic compounds, especially those rich in T, have attracted considerable attention owing to their potential application as permanent magnets. The stability, crystal structure and magnetic properties of RT13-xMx(R=La,Ce,Pr,Nd; T=Co,Fe; M=Al,Si) were investigated by means of x-ray powder diffraction and magnetic measurements. Cubic NaZn13-type or its derivative structure was obtained in LaCo13-xAlx(0 x 2.7), LaCo13-xSix (0 x 5.0),LaFe13-xAlx (1.95 x 7.15), LaFe13-xSix (1.4 x 5.0), CeCo13-xSix (3.2 x 4.0); CeFe13-xSix (2.4 x 2.6), PrCo13-xSix(1.5 x 4.0), NdCo13-xSix (2.5 x 4.0), LaCo13-xFex (0 x 6), LaFe3Co10-xSix (0 x 4.0), LaCo10-xFexSi3 (0 x 5), La1-xCexFe10.5Si2.5 (0 x 1) and La1-xRxCo9Fe4 (0 x 0.2). When T and M distribute randomly in the structure, R(T,M)13 belongs to cubic NaZn13-type structure, which could be transformed to a tetragonal or orthorhombic NaZn13-derivative structure in some composition regions by proper heat treatments. The composition dependences of Curie temperature and saturation magnetization of R(T,M)13 compounds were studied. The magnetocrystalline anisotropy in the NaZn13-derivative structure is generally a little larger than that in the cubic NaZn13-type structure. The relationship between crystal structure and magnetic properties was discussed.