Accession Number : AD0616092

Title :   ANTIFERROMAGNETIC RESONANCE LINEWIDTH IN MNF2 NEAR THE TRANSITION TEMPERATURE,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE RESEARCH LAB OF ELECTRONICS

Personal Author(s) : Burgiel,J. C. ; Strandberg,M. W. P.

Report Date : 01 SEP 1964

Pagination or Media Count : 12

Abstract : The antiferromagnetic resonance (AFMR) linewidth of MnF2 was studied near the Neel temperature. In the presence of an applied magnetic field, the linewidth diverges approximately as the absolute value of (T-Tn) to the -5/6th power. In the absence of an applied field, the line-width is larger and diverges approximately as the absolute value of (T-Tn) to the -4/3rd power. The linewidth is independent of the direction of the magnetic field and is the same for both branches of the AFMR spectrum. Though qualitative attempts to explain the temperature dependence both in the presence and absence of an applied magnetic field were made, a detailed theoretical explanation is still lacking. The independence of the linewidth on applied magnetic field direction and on AFMR mode are what we expect intuitively, although work by Mori and Kawasaki suggests that the linewidths for the two branches of the AFMR spectrum ought to be different. Above T sub n, the electron paramagnetic resonance (EPR) in MnF2 was observed. For H parallel to c, at temperatures near T sub n, the linewidth increases approximately as the absolute value of (T-Tn) to the -3/8th power. A smaller increase occurs for H perpendicular to c. The EPR data are discussed relative to the work of Heller and Benedek and of Moriya. (Author)

Descriptors :   (*ANTIFERROMAGNETISM, MANGANESE COMPOUNDS), (*MANGANESE COMPOUNDS, FLUORIDES), (*TRANSITION TEMPERATURE, MANGANESE COMPOUNDS), (*LINE SPECTRA, RESONANCE), MAGNETIC FIELDS, TEMPERATURE, DENSITY, PARAMAGNETIC RESONANCE

Distribution Statement : APPROVED FOR PUBLIC RELEASE