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Title: Low-energy magnon dynamics and magneto-optics of the skyrmionic Mott insulator Cu 2 OSeO 3

Abstract

In this study, we present a comprehensive study of the low-energy optical magnetic response of the skyrmionic Mott insulator Cu 2 OSeO 3 via high resolution time-domain THz spectroscopy. In zero field, a new magnetic excitation ( f 0 = 2.03 THz ) which has not been predicted by spin-wave theory is observed and shown, with accompanying time-of-flight neutron scattering experiments, to be a zone folded magnon from the R to Γ points of the Brillouin zone. Highly sensitive polarimetry experiments performed in weak magnetic fields, μ 0 H < 200 mT , observe Faraday and Kerr rotations which are proportional to the sample magnetization, allowing for optical detection of the skyrmion phase and construction of a magnetic phase diagram. From these measurements, we extract a critical exponent of β = 0.35 ± 0.04 , in good agreement with the expected value for the 3D Heisenberg universality class of β = 0.367 . In large magnetic fields, μ 0 H > 5 T , we observe the magnetically active uniform mode of the ferrimagnetic field polarized phase whose dynamics as a function of field and temperature are studied. In addition to extracting a g eff = 2.08 ± 0.03 , we observe the uniform mode to decay through a non-Gilbert damping mechanism and to possess a finite spontaneous decay rate, Γ 0 25 GHz , in the zero temperature limit. Finally, our observations are attributed to Dzyaloshinkii-Moriya interactions, which have been proposed to be exceptionally strong in Cu 2 OSeO 3 and are expected to impact the low-energy magnetic response of such chiral magnets.

Authors:
 [1];  [1];  [2];  [1];  [3];  [4];  [5];  [1]
  1. Johns Hopkins Univ., Baltimore, MD (United States). Inst. for Quantum Matter. Dept. of Physics and Astronomy
  2. Johns Hopkins Univ., Baltimore, MD (United States). Inst. for Quantum Matter. Dept. of Physics and Astronomy. Dept. of Chemistry
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Quantum Condensed Matter Division
  4. Johns Hopkins Univ., Baltimore, MD (United States). Inst. for Quantum Matter. Dept. of Physics and Astronomy. Dept. of Chemistry. Dept. of Materials Science and Engineering
  5. Johns Hopkins Univ., Baltimore, MD (United States). Inst. for Quantum Matter. Dept. of Physics and Astronomy. Dept. of Materials Science and Engineering
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Johns Hopkins Univ., Baltimore, MD (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF); ARCS Foundation (United States)
OSTI Identifier:
1474719
Alternate Identifier(s):
OSTI ID: 1372525
Grant/Contract Number:  
AC05-00OR22725; FG02-08ER46544; DGE-1232825
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 95; Journal Issue: 23; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Faraday effect; ferrimagnetism; insulators; Kerr effect; magnetic order parameter; magnetic susceptibility; order parameters; spin waves; topological phases of matter

Citation Formats

Laurita, N. J., Marcus, G. G., Trump, B. A., Kindervater, J., Stone, M. B., McQueen, T. M., Broholm, C. L., and Armitage, N. P. Low-energy magnon dynamics and magneto-optics of the skyrmionic Mott insulator Cu2OSeO3. United States: N. p., 2017. Web. doi:10.1103/PhysRevB.95.235155.
Laurita, N. J., Marcus, G. G., Trump, B. A., Kindervater, J., Stone, M. B., McQueen, T. M., Broholm, C. L., & Armitage, N. P. Low-energy magnon dynamics and magneto-optics of the skyrmionic Mott insulator Cu2OSeO3. United States. doi:10.1103/PhysRevB.95.235155.
Laurita, N. J., Marcus, G. G., Trump, B. A., Kindervater, J., Stone, M. B., McQueen, T. M., Broholm, C. L., and Armitage, N. P. Thu . "Low-energy magnon dynamics and magneto-optics of the skyrmionic Mott insulator Cu2OSeO3". United States. doi:10.1103/PhysRevB.95.235155. https://www.osti.gov/servlets/purl/1474719.
@article{osti_1474719,
title = {Low-energy magnon dynamics and magneto-optics of the skyrmionic Mott insulator Cu2OSeO3},
author = {Laurita, N. J. and Marcus, G. G. and Trump, B. A. and Kindervater, J. and Stone, M. B. and McQueen, T. M. and Broholm, C. L. and Armitage, N. P.},
abstractNote = {In this study, we present a comprehensive study of the low-energy optical magnetic response of the skyrmionic Mott insulator Cu2OSeO3 via high resolution time-domain THz spectroscopy. In zero field, a new magnetic excitation (f0=2.03THz) which has not been predicted by spin-wave theory is observed and shown, with accompanying time-of-flight neutron scattering experiments, to be a zone folded magnon from the R to Γ points of the Brillouin zone. Highly sensitive polarimetry experiments performed in weak magnetic fields, μ0H<200mT, observe Faraday and Kerr rotations which are proportional to the sample magnetization, allowing for optical detection of the skyrmion phase and construction of a magnetic phase diagram. From these measurements, we extract a critical exponent of β=0.35±0.04, in good agreement with the expected value for the 3D Heisenberg universality class of β=0.367. In large magnetic fields, μ0H>5T, we observe the magnetically active uniform mode of the ferrimagnetic field polarized phase whose dynamics as a function of field and temperature are studied. In addition to extracting a geff=2.08±0.03, we observe the uniform mode to decay through a non-Gilbert damping mechanism and to possess a finite spontaneous decay rate, Γ0≈25GHz, in the zero temperature limit. Finally, our observations are attributed to Dzyaloshinkii-Moriya interactions, which have been proposed to be exceptionally strong in Cu2OSeO3 and are expected to impact the low-energy magnetic response of such chiral magnets.},
doi = {10.1103/PhysRevB.95.235155},
journal = {Physical Review B},
number = 23,
volume = 95,
place = {United States},
year = {Thu Jun 29 00:00:00 EDT 2017},
month = {Thu Jun 29 00:00:00 EDT 2017}
}

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Works referenced in this record:

Spontaneous skyrmion ground states in magnetic metals
journal, August 2006

  • Rößler, U. K.; Bogdanov, A. N.; Pfleiderer, C.
  • Nature, Vol. 442, Issue 7104, p. 797-801
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