Accession Number : AD0276118

Title :   NUCLEAR MAGNETIC RESONANCE WITHIN AN ANTIFERRO-MAGNETIC BLOCH WALL

Corporate Author : CALIFORNIA UNIV LOS ANGELES

Personal Author(s) : PAUL,DAVID I.

Report Date : DEC 1961

Pagination or Media Count : 1

Abstract : The effect of bound spin wave excitation spectrum existing within an antiferromagnetic Bloch wall is calculated on the line width and relaxation times of the magnetic resonance of nuclei existing within the wall. A relaxation time, caused by excitation of the transverse components of the electron spin by the resonance field, is shown to be smaller in antiferromagnets than in ferromagnets due to the larger minimum wall excitation energy. The line width due to indirect coupling of the nuclear spins through the virtual excitation of a spin wave, however, proves to be increased by the square root of the ratio of the anisotropy to the stiffness parameters compared to the uniform antiferromagnet. This may account for the rather large line widths observed in NMR experiments in antiferromagnets. A second nuclear line width, resulting from the variation of the deviation of the longitudinal component of the electron spin from the center to the edge of the wall is also calculated. Numerical results are obtained and, where possible, compared with experiment. (Author)

Descriptors :   *FERROMAGNETISM, *NUCLEAR SPINS, ELECTRON IRRADIATION, NUCLEI, PARTIAL DIFFERENTIAL EQUATIONS, RELAXATION TIME, RESONANCE, SPINNING(MOTION)

Distribution Statement : APPROVED FOR PUBLIC RELEASE