MAGNETIC CHARACTERISTICS OF LAVES PHASE COMPOUNDS CONTAINING 2 LANTHANIDES WITH ALUMINUM

Magnetic properties are reported for twelve intermetallic systems designated by LnxLn'1-xAl2 where Ln and Ln' are two different lanthanide metals. All compounds have the MgCu2 structure (cubic Laves phase). Emphasis has been placed on the coupling mode at low temperatures to elaborate upon the general nature of the magnetic interactions in these compounds. All the compounds exhibited Curie-Weiss behavior above the transition temperature and had effective moment in good agreement with the g√J(J+ 1) values for the free ions. The paramagnetic moments indicate that the Ln ions are in the tripositive valence state for all systems except those containing Eu; Eu is dipositive. In the magnetically ordered state spins are observed to couple always ferromagnetically when Ln and Ln' are both tripositive. Saturation moments in many cases are less than expected from gJ, presumably due to carystal field quenching effects. CeAl2 is antiferromagnetic below 4°K. Direct exchange is probably the dominant interaction in this compound. Ce1-xEuxAl2 ternaries with x≥ 0.8 are antiferromagnetic at 4°K. For 0.2 ≥ x ≥ 0.6 these ternaries are paramagnetic at 4°K. © 1968.