Accession Number : AD0668458

Title :   THEORY OF FERRIMAGNETISM IN INSULATORS.

Descriptive Note : Final rept.,

Corporate Author : BATTELLE MEMORIAL INST COLUMBUS OHIO COLUMBUS LABS

Personal Author(s) : Kenan,Richard P.

Report Date : 06 MAR 1968

Pagination or Media Count : 6

Abstract : The purposes of this investigation have been to develop, with as much rigor as possible, improved spin-wave theories, to use the theories developed to obtain interpretive formulas for the transition temperature, dispersion curves, and the thermodynamic properties of magnetic insulators, and, somewhat more specialized, to explain the anomalous magnitude of the low-temperature heat capacity of a large number of ferrites, typified by magnetite. There have been three principal accomplishments: (1) A theory of spin-waves in ferrites of arbitrary structure and general exchange constants has been derived; (2) A theory of the effect of statistical interference among spin-waves, resulting from the operation of the Pauli principle, has been developed for a system of spins of magnitude one-half with antiferromagnetic exchange; and (3) A theory of the possible influence of magnetostatic modes of oscillation of the spin system on the heat capacity of ferrites was derived. In addition to these results, research has been carried out and is continuing on the application of functional techniques to the derivation of more reliable spin-wave theories, and on the application of the theory (1), above, to the metamagnetic transition metal chlorides.

Descriptors :   (*MAGNETIC MOMENTS, INTERACTIONS), (*FERRITES, THERMODYNAMICS), TRANSITION TEMPERATURE, MAGNETITE, CRYSTAL LATTICES, SPECIFIC HEAT, ANOMALIES, ANTIFERROMAGNETISM

Subject Categories : Electricity and Magnetism
      Solid State Physics
      Thermodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE