Accession Number : AD0726429

Title :   Low Temperature Specific Heat of Ni(NO3)2.6H2O; Antiferromagnetic Interactions.

Descriptive Note : Technical rept.,

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

Personal Author(s) : Herweijer,A. ; Friedberg,S. A.

Report Date : 01 JUL 1971

Pagination or Media Count : 17

Abstract : Measurements of the specific heat of nickel nitrate hexahydrate for 0.5 < T < 12K reveal a Schottky anomaly with Cp max=1.373 cal/mole-K at T(max)=2.35K. The experimental data are explained by the complete splitting of the S=1 ground state triplet, with levels separated successively by 4.80K and 3.26K. The lattice contribution is found to be 4.11 x 10 to the -4th power x (T cubed) cal/mole-K. The discrepancies between the level spacings as deduced from these measurements and from the reported powder susceptibility data are removed by taking into account a small antiferromagnetic exchange interaction (A/k = +0.6K) in a molecular field approximation. The total magnetic entropy change is found to be within 0.6% of the theoretically predicted value for a spin 1 system. (Author)

Descriptors :   (*SPECIFIC HEAT, NICKEL COMPOUNDS), (*ANTIFERROMAGNETISM, NICKEL COMPOUNDS), HYDRATES, NITRATES, CRYOGENICS, MAGNETIC MOMENTS, INTERACTIONS

Subject Categories : Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE