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Title: Long-wavelength correlations in ferromagnetic titanate pyrochlores as revealed by small-angle neutron scattering

Abstract

Here, we have carried out small angle neutron scattering measurements on single crystals of two members of the family of cubic rare-earth titanate pyrochlores that display ferromagnetic Curie-Weiss susceptibilities, Yb 2Ti 2O 7 and Ho 2Ti 2O 7. Ho 2Ti 2O 7 is established as displaying a prototypical classical dipolar spin ice ground state, while Yb 2Ti 2O 7 has been purported as a candidate for a quantum spin ice ground state. While both materials have been well studied with neutron scattering techniques, neither has been previously explored in single crystal form with small angle neutron scattering (SANS). Our results for Yb 2Ti 2O 7 show distinct SANS features below its Θ CW~0.50K, with rods of diffuse scattering extending along < 111 > directions in reciprocal space, off-rod scattering which peaks in temperature near Θ CW, and quasi-Bragg scattering at very small angles which correlates well with TC~0.26K. The quasi-Bragg scattering corresponds to finite extent ferromagnetic domains ~140Å across, at the lowest temperatures. We interpret the < 111 > rods of diffuse scattering as arising from domain boundaries between the finite-extent ferromagnetic domains. In contrast the SANS signal in Ho 2Ti 2O 7 is isotropic within the (HHL) plane aroundmore » Q = 0, consistent with the expectations of the dipolar spin ice model. However the strength of this overall SANS signal has a temperature dependence resembling that of the magnetic heat capacity, with a peak near 3 K. Below the break between the field-cooled and the zero-field cooled susceptibility in Ho 2Ti 2O 7 at ~0.60K, the SANS signal is very low, approaching zero.« less

Authors:
 [1];  [1]; ORCiD logo [2];  [3];  [3];  [1];  [1];  [4];  [3];  [5]
  1. McMaster Univ., Hamilton, ON (Canada)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Univ. of Waterloo, Waterloo, ON (Canada)
  4. Brockhouse Institute for Materials Research, Hamilton, ON (Canada)
  5. McMaster Univ., Hamilton, ON (Canada); Canadian Institute for Advanced Research, Toronto, ON (Canada); Brockhouse Institute for Materials Research, Hamilton, ON (Canada)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1464023
Alternate Identifier(s):
OSTI ID: 1440275
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 97; Journal Issue: 22; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Buhariwalla, C. R. C., Ma, Q., DeBeer-Schmitt, Lisa M., Xie, K. G. S., Pomaranski, D., Gaudet, J., Munsie, T. J., Dabkowska, H. A., Kycia, J. B., and Gaulin, Bruce D. Long-wavelength correlations in ferromagnetic titanate pyrochlores as revealed by small-angle neutron scattering. United States: N. p., 2018. Web. doi:10.1103/PhysRevB.97.224401.
Buhariwalla, C. R. C., Ma, Q., DeBeer-Schmitt, Lisa M., Xie, K. G. S., Pomaranski, D., Gaudet, J., Munsie, T. J., Dabkowska, H. A., Kycia, J. B., & Gaulin, Bruce D. Long-wavelength correlations in ferromagnetic titanate pyrochlores as revealed by small-angle neutron scattering. United States. doi:10.1103/PhysRevB.97.224401.
Buhariwalla, C. R. C., Ma, Q., DeBeer-Schmitt, Lisa M., Xie, K. G. S., Pomaranski, D., Gaudet, J., Munsie, T. J., Dabkowska, H. A., Kycia, J. B., and Gaulin, Bruce D. Mon . "Long-wavelength correlations in ferromagnetic titanate pyrochlores as revealed by small-angle neutron scattering". United States. doi:10.1103/PhysRevB.97.224401.
@article{osti_1464023,
title = {Long-wavelength correlations in ferromagnetic titanate pyrochlores as revealed by small-angle neutron scattering},
author = {Buhariwalla, C. R. C. and Ma, Q. and DeBeer-Schmitt, Lisa M. and Xie, K. G. S. and Pomaranski, D. and Gaudet, J. and Munsie, T. J. and Dabkowska, H. A. and Kycia, J. B. and Gaulin, Bruce D.},
abstractNote = {Here, we have carried out small angle neutron scattering measurements on single crystals of two members of the family of cubic rare-earth titanate pyrochlores that display ferromagnetic Curie-Weiss susceptibilities, Yb2Ti2O7 and Ho2Ti2O7. Ho2Ti2O7 is established as displaying a prototypical classical dipolar spin ice ground state, while Yb2Ti2O7 has been purported as a candidate for a quantum spin ice ground state. While both materials have been well studied with neutron scattering techniques, neither has been previously explored in single crystal form with small angle neutron scattering (SANS). Our results for Yb2Ti2O7 show distinct SANS features below its ΘCW~0.50K, with rods of diffuse scattering extending along < 111 > directions in reciprocal space, off-rod scattering which peaks in temperature near ΘCW, and quasi-Bragg scattering at very small angles which correlates well with TC~0.26K. The quasi-Bragg scattering corresponds to finite extent ferromagnetic domains ~140Å across, at the lowest temperatures. We interpret the < 111 > rods of diffuse scattering as arising from domain boundaries between the finite-extent ferromagnetic domains. In contrast the SANS signal in Ho2Ti2O7 is isotropic within the (HHL) plane around Q = 0, consistent with the expectations of the dipolar spin ice model. However the strength of this overall SANS signal has a temperature dependence resembling that of the magnetic heat capacity, with a peak near 3 K. Below the break between the field-cooled and the zero-field cooled susceptibility in Ho2Ti2O7 at ~0.60K, the SANS signal is very low, approaching zero.},
doi = {10.1103/PhysRevB.97.224401},
journal = {Physical Review B},
number = 22,
volume = 97,
place = {United States},
year = {Mon Jun 04 00:00:00 EDT 2018},
month = {Mon Jun 04 00:00:00 EDT 2018}
}

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