Accession Number:

AD0611500

Title:

STUDIES OF THE INTERNAL FIELDS ACTING ON NUCLEI IN FERROMAGNETIC AND PARAMAGNETIC SOLIDS, USING RECOIL-FREE RESONANCE, ABSORPTION (MOSSBAUER EFFECT),

Descriptive Note:

Corporate Author:

HEBREW UNIV JERUSALEM (ISRAEL)

Report Date:

1962-01-01

Pagination or Media Count:

2.0

Abstract:

Recoil-free gamma ray absorption spectra have been observed in ferromagnetic and paramagnetic solids containing nuclei of Fe57 and Dy161, using radioactive sources of Co57 and Tb161. The hyperfine Zeeman splittings in ferromagnetic materials permit a determination of the effective magnetic field at the nuclei. The effective magnetic field, H, at Fe57 nuclei in yttrium iron garnet, dysprosium iron garnet and in some spinel ferrites have been measured at 300K and 85K. Measurements on Fe3O4 confirm Verweys hypothesis of a fast exchange between ferrous and ferric ions in the octahedral sites above the transition temperature. H at Dy161 in dysprosium iron garnet has been found to be 3,500,000 oe at 85K and 750,000 oe at 300K and is proportional to the Dy sub-lattice spontaneous magnetization. A large temperature dependent quadrupole interaction in DIG has been observed, which is ascribed to an effective electric field gradient at the Dy nuclei produced by the partially aligned orbitals of the 4f electrons, and thus correlated with the spontaneous magnetization. Author

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Distribution Statement:

APPROVED FOR PUBLIC RELEASE