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Title: Quasistationary Criticality of the Order Parameter of the Three-Dimensional Random-Field Ising Antiferromagnet Fe0.85Zn0.15F2: a Synchrotron X-Ray Scattering Study

Abstract

No abstract prepared.

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
897449
Report Number(s):
SLAC-REPRINT-2006-178
TRN: US0701511
DOE Contract Number:
AC02-76SF00515
Resource Type:
Journal Article
Resource Relation:
Journal Name: Phys.Rev.B74:144431,2006
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; CRITICALITY; ORDER PARAMETERS; SCATTERING; SYNCHROTRONS; ANTIFERROMAGNETISM; Other,OTHER

Citation Formats

Ye, F., Zhou, L., Meyer, S.A., Shelton, L.J., Belanger, D.P., Lu, L., Larochelle, S., Greven, M., and /UC, Santa Cruz /SLAC, SSRL /Stanford U., Appl. Phys. Dept. /Stanford U., Phys. Dept. Quasistationary Criticality of the Order Parameter of the Three-Dimensional Random-Field Ising Antiferromagnet Fe0.85Zn0.15F2: a Synchrotron X-Ray Scattering Study. United States: N. p., 2007. Web.
Ye, F., Zhou, L., Meyer, S.A., Shelton, L.J., Belanger, D.P., Lu, L., Larochelle, S., Greven, M., & /UC, Santa Cruz /SLAC, SSRL /Stanford U., Appl. Phys. Dept. /Stanford U., Phys. Dept. Quasistationary Criticality of the Order Parameter of the Three-Dimensional Random-Field Ising Antiferromagnet Fe0.85Zn0.15F2: a Synchrotron X-Ray Scattering Study. United States.
Ye, F., Zhou, L., Meyer, S.A., Shelton, L.J., Belanger, D.P., Lu, L., Larochelle, S., Greven, M., and /UC, Santa Cruz /SLAC, SSRL /Stanford U., Appl. Phys. Dept. /Stanford U., Phys. Dept. Fri . "Quasistationary Criticality of the Order Parameter of the Three-Dimensional Random-Field Ising Antiferromagnet Fe0.85Zn0.15F2: a Synchrotron X-Ray Scattering Study". United States. doi:.
@article{osti_897449,
title = {Quasistationary Criticality of the Order Parameter of the Three-Dimensional Random-Field Ising Antiferromagnet Fe0.85Zn0.15F2: a Synchrotron X-Ray Scattering Study},
author = {Ye, F. and Zhou, L. and Meyer, S.A. and Shelton, L.J. and Belanger, D.P. and Lu, L. and Larochelle, S. and Greven, M. and /UC, Santa Cruz /SLAC, SSRL /Stanford U., Appl. Phys. Dept. /Stanford U., Phys. Dept.},
abstractNote = {No abstract prepared.},
doi = {},
journal = {Phys.Rev.B74:144431,2006},
number = ,
volume = ,
place = {United States},
year = {Fri Jan 12 00:00:00 EST 2007},
month = {Fri Jan 12 00:00:00 EST 2007}
}
  • The critical exponent {beta}=0.17{+-}0.01, where the quoted statistical error is from fits to the data, has been determined for the three-dimensional random-field Ising model (RFIM) order parameter upon zero-field cooling (ZFC) using extinction-free magnetic x-ray scattering techniques for Fe{sub 0.85}Zn{sub 0.15}F{sub 2}. This result is consistent with other exponents determined for the RFIM in that Rushbrooke scaling is satisfied. Nevertheless, there is poor agreement with equilibrium computer simulations, and the ZFC results do not agree with field-cooling results. We present details of hysteresis in Bragg scattering amplitudes and line shapes that help elucidate the effects of thermal cycling in themore » RFIM, as realized in dilute antiferromagnets in an applied field. We show that the ZFC critical-like behavior is consistent with a second-order phase transitions, albeit quasistationary rather than truly equilibrium in nature, as evident from the large thermal hysteresis observed near the transition.« less
  • 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 samplemore » 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.« less
  • We report a magnetic neutron and x-ray scattering study of the correlation length and order parameter of the random-field Ising magnets Fe{sub 0.5}Zn{sub 0.5}F{sub 2} and Mn{sub 0.45}Zn{sub 0.55}F{sub 2} on field cooling. Fitting the inverse correlation length, {kappa}, measured above the metastability temperature, T{sub M}(H) in Fe{sub 0.5}Zn{sub 0.5}F{sub 2}, at H=5 and 6 T to a power law yields the exponent {nu}=1.5{plus_minus}0.3 together with the equilibrium transition temperatures, T{sub N}(H), which are found to be well below T{sub M}(H). We also estimate {gamma}=2.6{plus_minus}0.5 and {bar {gamma}}=5.7{plus_minus}1 for the connected susceptibility, {chi}, and the disconnected susceptibility, {chi}{sub dis}, exponents,more » respectively. The x-ray data reveal a long range ordered component coexisting with short range magnetic order in the field-cooled state, for weak random fieldsin both samples. The nucleation of the long range order occurs below T{sub M}(H). The intensity of the long range order component decreases with increasing field. {copyright} {ital 1997} {ital The American Physical Society}« less
  • We report a resonant x-ray-scattering determination of order parameter of the Nd sublattice in the quasi-one-dimensional antiferromagnet, Nd{sub 2}BaNiO{sub 5}. We find that long-range order develops below {ital T}{sub {ital N}}=48 K, and that the staggered magnetization continues to grow down to {ital T}=10 K. This is in contrast with the behavior of the Ni sublattice, which quickly saturates, as determined previously by neutron-scattering. We find this behavior is modeled well by a self-consistent mean-field theory. Large resonant enhancements were obtained at both the Nd {ital L}{sub II} and {ital L}{sub III} absorption edges, with the largest count rates beingmore » achieved at the {ital L}{sub II} edge, where structure consistent with magnetic diffraction anomalous fine structure was observed. A double peak observed at the {ital L}{sub III} resonance is also discussed. {copyright} {ital 1996 The American Physical Society.}« less