Neutron scattering study of the effect of a random field on the three-dimensional dilute Ising antiferromagnet Fe/sub 0. 6/Zn/sub 0. 4/F/sub 2/

Journal Article · Mon Apr 01 00:00:00 EST 1985 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.31.4548· OSTI ID:6727239

Yoshizawa, H; Cowley, R A; Shirane, G

The authors report a comprehensive neutron scattering study of random-field effects in the three-dimensional Ising antiferromagnet Fe/sub 0.6/Zn/sub 0.4/F/sub 2/. The sample is the same one used in high-precision birefringence studies. The scattering is dependent on the prior history of the sample at all temperatures below a well-defined temperature which agrees with the phase boundary reported in the birefringence studies to within 0.2 K. When the sample is cooled in a field (FC), long-range order is not established and the scattering has a Lorentzian-squared profile with a width K approx. = H/sup 2/. On the other hand, when the sample is cooled in zero field into the Neel state, the field raised and the temperature then increased (ZFC), the scattering close to the phase boundary consists of an antiferromagnetic Bragg component superimposed on scattering which is characteristic of the FC procedure. The Bragg component is absent when the crystal is heated above the phase boundary. In addition, if after field cooling the system is heated, the width of the scattering is unchanged until the phase boundary is reached. None of the existing d/sub 1/ = 2 low-temperature theories explains such behavior in the vicinity of the phase boundary. Above the phase boundary ZFC and FC results agree, indicating that the system is always in equilibrium. The authors have studied the critical behavior in this region and the scattering is very different from that with H = 0. Specifically, the scattering profiles show a large Lorentzian-squared component and over a limited temperature range the inverse correlation length varies linearly with temperature. 21 references, 14 figures.

• Research Organization: Brookhaven National Lab., Upton, NY
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 6727239
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Vol. 31:7
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
IRON FLUORIDES
ELECTRONIC STRUCTURE
ZINC FLUORIDES
ANTIFERROMAGNETISM
EXPERIMENTAL DATA
ISING MODEL
LINE WIDTHS
NEUTRON DIFFRACTION
NEUTRON SPECTRA
ORDER-DISORDER TRANSFORMATIONS
PHASE TRANSFORMATIONS
TEMPERATURE DEPENDENCE
TIME DEPENDENCE
COHERENT SCATTERING
CRYSTAL MODELS
DATA
DIFFRACTION
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
INFORMATION
IRON COMPOUNDS
MAGNETISM
MATHEMATICAL MODELS
NUMERICAL DATA
SCATTERING
SPECTRA
TRANSITION ELEMENT COMPOUNDS
ZINC COMPOUNDS
ZINC HALIDES
360603* - Materials- Properties
360602 - Other Materials- Structure & Phase Studies
656002 - Condensed Matter Physics- General Techniques in Condensed Matter- (1987-)