Lowhyphen;Temperature Magnetic Susceptibilities of Some Hydrated Formates of Cu++and Mn++

摘要

The magnetic susceptibilities of powdered specimens of Cu(HCO2)2middot;4H2O, Cu(HCO2)2middot;2H2O, and Mn(HCO2)2middot;2H2O have been measured by an audiohyphen;frequency mutualhyphen;inductance method between 1.3deg; and 4.2deg;K, and from 14deg; to 20deg;K. At hydrogen temperatures Cu(HCO2)2middot;2H2O and Mn(HCO2)2middot;2H2O exhibit Curiemdash;Weiss behavior which, however, breaks down significantly in the helium region. The susceptibility of Cu(HCO2)2middot;4H2O rises to a pronounced peak at 16.8deg;K and is essentially constant below 4.2deg;K. The susceptibilities of singlehyphen;crystal Cu(HCO2)2middot;4H2O were measured along the three monoclinic axes in the same temperature intervals. khgr;cand khgr;bshow sharp maxima at 16.8deg;, and are much larger in magnitude than khgr;a. The possibility of this salt becoming weakly ferromagnetic below 16.8deg;K is considered, as is the unusual indirecthyphen;exchange coupling of Cu++moments via formate groups.