Magnetic Susceptibilities of Several Paramagnetic Salts at Liquid He3 Temperatures

Abstract
A cryostat is described in which magnetic susceptibility measurements may be made by an audio‐frequency mutual induction technique at temperatures down to 0.35°K. Below 2°K the specimens are in direct contact with liquid He3. Results of measurements on several compounds are presented. The powder susceptibility of [Cr3(CH3COO)6(OH)2]Cl·8H2O has been found to obey a Curie—Weiss law. Both powdered Co(CH3COO)2·4H2O and powdered Ni(CH3COO)2·4H2O are observed to be paramagnetic to the lowest temperatures attained; the former salt does not exhibit the anomaly at 0.6°K found in earlier studies employing a magnetic cooling technique. The powder susceptibility of Mn(HCOO)2·2H2O suggests the existence of significant coupling among many of the Mn++ moments, but no evidence was found of a cooperative transition above 0.56°K.