Accession Number : AD0716054

Title :   Mossbauer Effect and Optical Fluorescence Study of Fe(3+)In LiAl508.

Descriptive Note : Doctoral thesis,

Corporate Author : CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF PHYSICS

Personal Author(s) : Viccaro,P. James

Report Date : OCT 1970

Pagination or Media Count : 124

Abstract : 57Fe(3+) Mossbauer effect (ME) absorption spectra were collected for powder specimens of LiFe(x)Al(5-x)O8 with O < x < or = 5 and optical measurements were made of the fluorescence and excitation spectra of Fe(3+) for x = 0.004 and 0.005 ordered and disordered phase compounds. For ordered specimens with x < 0.01, the paramagnetic hyperfine spectrum is unusually well defined over the temperature range of 4.2K to 300K. The effects on the spectrum of external magnetic fields with strengths less than 1 kOe are interpreted in detail. Considered also are the perturbing effects of dipolar field originating from neighboring nuclei. In contrast no quadrupole interaction was observed for ferrimagnetic LiFe5O8 (ordered) below or above its Neel temperature. The Mossbauer effect spectra for the disordered phase compounds with x = 0.004 and 0.25 are presented. The fluorescence band of the ordered phase compounds consists of two components at 295K. Neither a zero phonon transition nor phonon side-bands are observed for temperatures as low as 77K. A consideration of site occupation by Fe(3+) in conjunction with these optical results is made. (Author)

Descriptors :   (*ALUMINATES, *FLUORESCENCE), (*MOSSBAUER EFFECT, *IRON COMPOUNDS), DOPING, FERRATES, LITHIUM COMPOUNDS, HYPERFINE STRUCTURE, PHONONS, CRYOGENICS, CRYSTAL DEFECTS, THESES

Subject Categories : Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE