NUCLEAR MAGNETIC RESONANCE IN PARAMAGNETIC MnF

Journal Article · Sun Dec 01 04:00:00 EST 1957 · Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D

DOI:https://doi.org/10.1103/PhysRev.108.1219· OSTI ID:4313056

Shulman, R G; Jaccarino, V

Nuclear magnetic resonances of F/sup 19/ in single crystals of paramagnetic MnF/sub 2/ were observed in the temperature region 68 to 300 deg K. Shifts of the resonances from the predicted field, omega / gamma , were as large as 8%. With the external magnetic field not in the ab plane, two separate resonances were observed corresponding to the two different F positions in the unit cell. Both the shifts and thc splittings were functions of magnetic field, temperature, and crystal orientation. As the temperature was increased, the line widths increased from 25 to 42 oe. These observations were explained by postulating a small degree of covalency in the F/sup -/ bond to the panamagnetic Mn/sup ++/ ion. Each bond includcs 0.48 plus or minus 0.02% F 2s character. The contributions of the 2p/sub sigma / and 2p/sub pi /orbitals are discussed and the effects of the covalency upon the longrangc order and the superexchange mechanism are considered. The lines disappeared abruptly at the Neel temperature, T/sub n/, (68 plus or minus l deg K) because the sudden increase in sublattice magnetization shifts them beyond the frequency range of the spectrometer. Attempts to observe the resonances at low tcmperatures are described. (auth)

• Research Organization: Bell Telephone Labs., Murray Hill, N.J.
• NSA Number: NSA-12-004405
• OSTI ID: 4313056
• Journal Information: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D, Journal Name: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D Vol. Vol: 108; ISSN PHRVA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ANTIFERROMAGNETISM
ATOMIC MODELS
BINDING ENERGY
CRYSTALS
FLUORINE 19
FREQUENCY
IONS
LATTICES
LOW TEMPERATURE
MAGNESIUM
MAGNESIUM FLUORIDES
MAGNETIC FIELDS
MAGNETIC RESONANCE
MAGNETISM
MANGANESE FLUORIDES
MEASURED VALUES
MONOCRYSTALS
NEEL TEMPERATURE
NUCLEAR MAGNETIC RESONANCE
PARAMAGNETISM
PHYSICS
SPECTRAL SHIFT
SPECTROMETERS
TEMPERATURE