Absorption and magneto-optical properties of the /sup 3/A/sub 2g/. -->. /sup 1/T/sub 2g//sup a/ transition in CsNiF/sub 3/. II. Pure-exciton and hot-magnon bands in a one-dimensional ferromagnet

Journal Article · Thu Aug 01 00:00:00 EDT 1985 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.32.1673· OSTI ID:5651707

Tsuboi, T; Laiho, R

Absorption spectra associated with the lowest-energy region of the spin-forbidden transition /sup 3/A/sub 2g/..-->.. /sup 1/T/sub 2g//sup a/ in CsNiF/sub 3/ are investigated in the one-dimensional ferromagnetic phase in magnetic fields up to 4.5 T. Pure-exciton bands are found to have a linear blue shift with a field applied in the easy plane, whereas the hot-magnon band shifts slightly to lower energies. When the field is increased the intensity of the exciton bands increases and the absorption due to the hot-magnon band decreases. An anomalous behavior of the band intensities and the half-widths is observed in fields below 1 T. The structure of the exciton spectra and their field dependence are discussed by using an energy-level scheme obtained by a single-ion approximation. The properties of the hot-magnon sideband are explained by the exciton creation accompanied by the annihilation of a thermally excited magnon at the Brillouin-zone edge. The anomalies of the exciton and the hot-magnon bands observed in low fields may be understood by the reduction of spin fluctuations in a magnetic field applied in the easy plane of magnetization.

• Research Organization: Physics Department, Kyoto Sangyo University, Kyoto 603, Japan
• OSTI ID: 5651707
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Vol. 32:3
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CESIUM FLUORIDES
MAGNETO-OPTICAL EFFECTS
MAGNONS
NICKEL FLUORIDES
ABSORPTION
ENERGY LEVELS
EXCITONS
FERROMAGNETIC MATERIALS
FORBIDDEN TRANSITIONS
MAGNETIC FIELDS
ALKALI METAL COMPOUNDS
CESIUM COMPOUNDS
ENERGY-LEVEL TRANSITIONS
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
MAGNETIC MATERIALS
MATERIALS
NICKEL COMPOUNDS
QUASI PARTICLES
TRANSITION ELEMENT COMPOUNDS
360603* - Materials- Properties