Accession Number : AD0601726

Title :   STATISTICAL MECHANICS AND PHASE TRANSITIONS OF THE HEISENBERG ANTIFERROMAGNET.

Descriptive Note : Technical rept. no. 15

Corporate Author : PENNSYLVANIA UNIV PHILADELPHIA

Personal Author(s) : Anderson,F. Burr ; Callen,Herbert B.

Report Date : APR 1964

Pagination or Media Count : 89

Abstract : The spin-flop and flop-para phase transitions of a simple uniaxial antiferromagnet are analyzed by a Green function analysis. The temperature dependence of the field for antiferromagnetic resonance, the parallel and perpendicular susceptibilities, and the sublattice magnetizations are also computed. It is shown that these effects are sensitive to the temperature dependent renormalization of spin wave energies, and this effect is analyzed in some detail. Results are in good semi quantitative agreement with AFMR in MnF2 and Cr2O3, with the phase transition boundaries in MnBr2.4H2O, and with the perpendicular susceptibility of MnF2, and they give reasonable estimates of the metamagnetic transitions in materials such as FeCO3 and FeBr2. (Author)

Descriptors :   (*ANTIFERROMAGNETISM, PHASE STUDIES), (*STATISTICAL MECHANICS, ANTIFERROMAGNETISM), MAGNETIC PROPERTIES, MAGNETIC FIELDS, PARAMAGNETIC MATERIALS, MAGNETIC RESONANCE, MANGANESE COMPOUNDS, OXIDES, CHROMIUM COMPOUNDS, FLUORIDES, BROMIDES, COPPER COMPOUNDS, IRON COMPOUNDS, MAGNETIC MATERIALS, PHASE SHIFT CIRCUITS, RUBIDIUM COMPOUNDS, MATHEMATICAL MODELS, THERMODYNAMICS, ANISOTROPY, TEMPERATURE

Distribution Statement : APPROVED FOR PUBLIC RELEASE