The Magnetic Properties of the Iron Group Anhydrous Chlorides at Low Temperatures. I. Experimental

The magnetic susceptibility of the anhydrous chlorides of the iron group have been studied as a function of field strength up to 32,000 gauss and as a function of temperature down to 13.9°K. Those compounds whose room temperature susceptibility characteristic indicates a positive Curie temperature, also show a field strength dependence of the susceptibility at 13.9°K and 20.4°K. Chromic chloride has a very steep magnetization curve at these low temperatures, with a large initial susceptibility increasing with decreasing temperature. Ferrous, cobaltous, and nickelous chlorides have an S-type magnetization curve characterized by a small initial susceptibility which decreases with decreasing temperature, followed by a very large susceptibility and eventual approach to saturation, both increasing with decreasing temperature. The susceptibility of many of the compounds reaches a maximum at temperatures which do not appear to be correlated with the presence of field dependence, but these temperatures do correspond to the temperatures of known specific heat anomalies.