ON THE MAGNETIC-BEHAVIOR OF RCO2 COMPOUNDS WHERE R IS YTTRIUM OR A RARE-EARTH

The magnetic susceptibilities of YCo2 and LuCo2 exchange-enhanced paramagnets, at high temperatures, obey a Curie-Weiss behaviour. The effective moments per cobalt atoms determined from the Curie constants are close to that of Co2+ ion. The above behaviour is in agreement with the prediction of the spin fluctuations theory of Moriya. The temperature ranges in which the previous models [5, 6] describe the paramagnetic behaviour of RCo2 compounds, where R is a magnetic heavy rare-earth, are analysed. The decrease of the effective cobalt moments in RCo2 compounds, when the Curie temperatures, exchange interactions, respectively increase, is attributed to the partial quenching of spin fluctuations.