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Title: Magnetic structures and excitations in a multiferroic Y-type hexaferrite BaSrCo 2 Fe 11 AlO 22

Here, we have investigated magnetic orders and excitations in a Y-type hexaferrite BaSrCo 2Fe 11AlO 22 (BSCoFAO), which was reported to exhibit spin-driven ferroelectricity at room temperature. By means of magnetization, electric polarization, and neutron-diffraction measurements using single-crystal samples, we establish a H-T magnetic phase diagram for magnetic field perpendicular to the c axis (H ⟂c). This system exhibits an alternating longitudinal conical (ALC) magnetic structure in the ground state, and it turns into a non-co-planar commensurate magnetic order with spin-driven ferroelectricity under H ⟂c. The field-induced ferroelectric phase remains as a metastable state after removing magnetic field below 250 K. This metastability is the key to understanding of magnetic field reversal of the spin-driven electric polarization in this system. Inelastic polarized neutron-scattering measurements in the ALC phase reveal a magnetic excitation at around 7.5 meV, which is attributed to spin components oscillating in a plane perpendicular to the cone axis. This phasonlike excitation is expected to be an electric-field active magnon, i.e., electromagnon excitation, in terms of the magnetostriction mechanism.
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [4] ;  [5] ;  [1] ;  [1] ;  [2]
  1. RIKEN Center for Emergent Matter Science, Saitama (Japan)
  2. RIKEN Center for Emergent Matter Science, Saitama (Japan); Univ. of Tokyo, Kashiwa (Japan)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); The Univ. of Tennessee, Knoxville, TN (United States)
  5. RIKEN Center for Emergent Matter Science, Saitama (Japan); Japan Atomic Energy Agency, Ibaraki (Japan); Comprehensive Research Organization for Science and Society, Ibaraki (Japan)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 94; Journal Issue: 19; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1337864
Alternate Identifier(s):
OSTI ID: 1333977

Nakajima, Taro, Tokunaga, Yusuke, Matsuda, Masaaki, Dissanayake, Sachith E., Fernandez-Baca, Jaime A., Kakurai, Kazuhisa, Taguchi, Yasujiro, Tokura, Yoshinori, and Arima, Taka-hisa. Magnetic structures and excitations in a multiferroic Y-type hexaferrite BaSrCo2Fe11AlO22. United States: N. p., Web. doi:10.1103/PhysRevB.94.195154.
Nakajima, Taro, Tokunaga, Yusuke, Matsuda, Masaaki, Dissanayake, Sachith E., Fernandez-Baca, Jaime A., Kakurai, Kazuhisa, Taguchi, Yasujiro, Tokura, Yoshinori, & Arima, Taka-hisa. Magnetic structures and excitations in a multiferroic Y-type hexaferrite BaSrCo2Fe11AlO22. United States. doi:10.1103/PhysRevB.94.195154.
Nakajima, Taro, Tokunaga, Yusuke, Matsuda, Masaaki, Dissanayake, Sachith E., Fernandez-Baca, Jaime A., Kakurai, Kazuhisa, Taguchi, Yasujiro, Tokura, Yoshinori, and Arima, Taka-hisa. 2016. "Magnetic structures and excitations in a multiferroic Y-type hexaferrite BaSrCo2Fe11AlO22". United States. doi:10.1103/PhysRevB.94.195154. https://www.osti.gov/servlets/purl/1337864.
@article{osti_1337864,
title = {Magnetic structures and excitations in a multiferroic Y-type hexaferrite BaSrCo2Fe11AlO22},
author = {Nakajima, Taro and Tokunaga, Yusuke and Matsuda, Masaaki and Dissanayake, Sachith E. and Fernandez-Baca, Jaime A. and Kakurai, Kazuhisa and Taguchi, Yasujiro and Tokura, Yoshinori and Arima, Taka-hisa},
abstractNote = {Here, we have investigated magnetic orders and excitations in a Y-type hexaferrite BaSrCo2Fe11AlO22 (BSCoFAO), which was reported to exhibit spin-driven ferroelectricity at room temperature. By means of magnetization, electric polarization, and neutron-diffraction measurements using single-crystal samples, we establish a H-T magnetic phase diagram for magnetic field perpendicular to the c axis (H⟂c). This system exhibits an alternating longitudinal conical (ALC) magnetic structure in the ground state, and it turns into a non-co-planar commensurate magnetic order with spin-driven ferroelectricity under H⟂c. The field-induced ferroelectric phase remains as a metastable state after removing magnetic field below 250 K. This metastability is the key to understanding of magnetic field reversal of the spin-driven electric polarization in this system. Inelastic polarized neutron-scattering measurements in the ALC phase reveal a magnetic excitation at around 7.5 meV, which is attributed to spin components oscillating in a plane perpendicular to the cone axis. This phasonlike excitation is expected to be an electric-field active magnon, i.e., electromagnon excitation, in terms of the magnetostriction mechanism.},
doi = {10.1103/PhysRevB.94.195154},
journal = {Physical Review B},
number = 19,
volume = 94,
place = {United States},
year = {2016},
month = {11}
}