LaCo13—xMx金属间化合物的结构和磁性

在任何已知的稀土中间相化合物中,LaCo_(13)具有最高的3d金属含量,且其饱和磁化强度很高为1.03 MA/m居里温度高达1318 K,不幸的是它是立方结构,不存在适合于永磁应用所必须时各向异性。本文对LaCo_(13-x)Si_x(x=2,4)和LaCo_(13-x)Ge_x(x=2,2.5,3,4)金属间化合物的结构和磁性能进行了研究,发现对LaCo_(13-x)Si_x当x=4和LaCo_(13-x)Ge_x当x=3,4时,其晶体结构为四方结构但晶格常数a,c的差值很小。对于LaCo_(13-x)Ge_x为得到该结构所需的时效温度很严格。磁性测量发现它们的居里温度都较高,但室温饱和磁化强度随x增加大大降低。

THE STRUCTURE AND MAGNETIC PROPERTIES OF LaCo_(13-x)M_x INTERMETALLIC COMPOUNDS

LaCo13 has the highest 3d metal content, of anyknown rare-earth intermetallic, a 1.03 MA/m saturation magnlhzation at room temperature and a high Tc(1318K) Unfortunately, It is cubic, lacking of the necessary anisotropy diminishs the chame that it will be msed as a permanent magnel. material The structure and magnetic properties of laCo13-xSix(x=2,4) and laCo13-xGex(x=2,2.S, 3,4)intermetallic compounds have been studied. The crystal structure was found to be tetragonal when x=4 for LaCo13-xSix and x=3, 4 for laCo13-xGex, but the difference between the lattice parameters a and c is very small. In order to gain the tetragonal structure, the ageing temperature of LaCo13-xGex must be controlled strictly. The magnetic measurement shows that the curie temperature of all these rompounds is high, but the saturation magnetization at room-temperature decreases greatly with the increasing of x.