Accession Number : AD0612472

Title :   TWO-PARTICLE CLUSTER THEORY OF ANTIFERROMAGNETISM,

Corporate Author : PENNSYLVANIA UNIV PHILADELPHIA

Personal Author(s) : Callen nn,Herbert B. ; Callen,Earl

Report Date : FEB 1965

Pagination or Media Count : 23

Abstract : The two-spin cluster theory of Strieb, Callen and Horwitz, is extended to antiferromagnets. The theory is formulated to include nearest and next-nearest neighbor exchange (J sub 1 and J sub 2) and to apply to those types of antiferromagnetic Neel phases in which equal numbers of spins are nominally 'up' and 'down'. When J sub 2 = 0 the theory reduces to the antiferromagnetic constant coupling theory of Kasteleijn and van Kranendonk. Consequently the theory suffers from the defect of an anti-Neel transition at low temperatures. (Author)

Descriptors :   (*ANTIFERROMAGNETISM, THEORY), (*SERIES(MATHEMATICS), ANTIFERROMAGNETISM), PERTURBATION THEORY, FIELD THEORY, SPINNING(MOTION), PHASE STUDIES, IONS, CRYSTAL LATTICES

Distribution Statement : APPROVED FOR PUBLIC RELEASE