MAGNETIC PROPERTIES OF THE HEXAGONAL ANTIFERROMAGNET CsMnF$sub 3$

Journal Article · Tue Oct 01 04:00:00 EDT 1963 · Physical Review (U.S.) Superseded in part by Phys.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.132.144· OSTI ID:4646543

Lee, K; Portis, A M; Witt, G L

The magnetic properties of the hexagonal antiferromagnet CsMnF/sub 3/ were investigated by magnetic susceptibility, torsion, electron resonance, and nuclear-antiferromagnetic double resonance. Torsion measurements establish a transition to an antiferromagnetically ordered state at 53.5 deg K. A weak sixfold anisotropy in the transverse plane and a large axial anisotropy along the c axis corresponding, respectively, to the fields 36K/sub 3//M = 1.1 and K/sub 1// M = --7500 oersted are detected. Susceptibility measurements at 4.2 deg K establish an exchange field H/sub e/ = 3.5 x 10/sup 5/ oersted. The temperature dependence of K/sub 3/ was observed from 4.2 deg K to the transition temperature and compared with spin-wave and molecular field theory. From paramagnetic resonance measurements an isotropic g value of 1.9989 plus or minus 0.003 is determined. Magnetic resonance measurements below the transition temperature with the applied field in the transverse plane show a weak sixfold anisotropy consistent with the torsion measurements. Measurements out of the transverse plane confirm the large axial anisotropy. In the temperature range from 0.3 to 4.2 deg K there is an additional temperature dependent anisotropy field H/sub A,T/ = 9.15/T oersted directed along the sublattices. This field arises from the hyperfine interaction with the Mn/sup 55/ nuclear magnetization. Assuming parallel ordering within the transverse planes with adjacent planes alternately magnetized, a calculation of the classical dipolar interactions and of the ligand field anisotropy arising from the displacement of the nearest neighbor fluorines gives a combined axial anisotropy field K/sub 1//M = -7965 oersted. The in-plane anisotropy due to second-order dipolar interactions is estimated to be approximately 2 oersted in reasonable agreement with observation. The strong coupling between the nuclei and electrons affords an opportunity to observe the Mn/sup 56/ nuclear resonance indirectly by monitoring the position of the electron resonance field. A saturation of the nuclear magnetization is observed at 668 Mc/sec which is (3 plus or minus 1)% smaller than the calculated average hyperfine field of 889 plus or minus 7 Mc/sec. This indicates the presence of a zero-point reduction in the electron spin. (auth)

• Research Organization: Univ. of California, Berkeley
• NSA Number: NSA-17-037852
• OSTI ID: 4646543
• 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: 132; ISSN PHRVA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ANISOTROPY
ANTIFERROMAGNETISM
CESIUM FLUORIDES
COUPLING
DEFORMATION
DIPOLES
ELECTRONS
FERROMAGNETIC MATERIALS
FERROMAGNETISM
FREQUENCY
GYROMAGNETIC RATIO
HYPERFINE STRUCTURE
INTERACTIONS
LATTICES
LAYERS
MAGNETIC FIELDS
MAGNETIC MOMENTS
MAGNETISM
MANGANESE 55
MANGANESE FLUORIDES
MEASURED VALUES
MONOCRYSTALS
NUCLEAR MAGNETIC RESONANCE
NUMERICALS
OSCILLATIONS
PARAMAGNETISM
PHYSICS
RESONANCE
ROTATION
SPIN
SPIN WAVES
SUSCEPTIBILITY
TEMPERATURE
TRANSIENTS