Accession Number : AD0676310

Title :   THE LOW TEMPERATURE MAGNETIZATION OF CU(NO3)2.2.5H2O.

Descriptive Note : Technical rept.,

Corporate Author : CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF PHYSICS

Personal Author(s) : Myers,B. E. ; Berger,L. ; Friedberg,S. A.

Report Date : 11 OCT 1968

Pagination or Media Count : 12

Abstract : Magnetization isotherms were measured for single crystals of monoclinic Cu(NO3)2.2.5H2O between 1.2 degrees and 4.2 degrees K by a ballistic method. Fields up to 43 kOe were applied along the b-axis, i.e. the long axis of the needlelike specimens. The character of the M vs. H curves changes rapidly in this temperature interval. They are described in first approximation by a model of this salt in which Cu++ ions are coupled by isotropic antiferromagnetic exchange, -JS sub 1.S sub 2, in isolated pairs. The best fit of the data with the isolated cluster model yields J = 5.23 k and g = 2.23, in reasonable agreement with earlier susceptibility, specific heat and proton resonance results. Several modifications of the model were considered in order to remove small systematic discrepancies. The addition of a very weak intercluster coupling in a molecular field approximation yields a quantitative fit of all the data. If H = H sub o + nM, we find n = -1.2 mole/cgs while J = -5.14 k and g = 2.35, in even closer agreement with other observations. This weak antiferromagnetic coupling is large enough to explain the absence of hyperfine structure on paramagnetic resonances seen in the excited pair triplet state. (Author)

Descriptors :   (*COPPER COMPOUNDS, MAGNETIC PROPERTIES), NITRATES, HYDRATES, SINGLE CRYSTALS, CRYOGENICS, PARAMAGNETIC RESONANCE, ANTIFERROMAGNETISM, ATOMIC ENERGY LEVELS, CORRELATION TECHNIQUES

Subject Categories : Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE