Spin dynamics of the pyrochlore magnets Gd2Ti2O7 and Gd2Sn2O7 in the paramagnetic state
Sosin, S. S., Prozorova, L. A., Smirnov, A. I., Bonville, P., Bras, G. Jasmin-Le and Petrenko, O. A.. (2008) Spin dynamics of the pyrochlore magnets Gd2Ti2O7 and Gd2Sn2O7 in the paramagnetic state. Physical Review B (Condensed Matter and Materials Physics), Volume 77 (Number 10). Article No. 104424 . ISSN 1098-0121Full text not available from this repository.
Official URL: http://dx.doi.org/10.1103/PhysRevB.77.104424
The strongly correlated disordered phase of two highly frustrated pyrochlore magnets Gd2Ti2O7 and Gd2Sn2O7 is probed using electron-spin resonance in the temperature range 1.3-30 K. The deviation of the absorption line from the paramagnetic position nu=gamma H observed in both compounds below the Curie-Weiss temperature Theta(CW)similar or equal to 10 K suggests an opening up of a gap in the excitation spectra. On cooling to 1.3 K (which is above the ordering transition T-N similar or equal to 1.0 K) the resonance spectrum is transformed into a wideband of excitations with the gap amounting to Delta similar or equal to 26 GHz (1.2 K) in Gd2Ti2O7 and 18 GHz (0.8 K) in Gd2Sn2O7. The gaps increase linearly with the external magnetic field. For Gd2Ti2O7 this branch coexists with an additional nearly paramagnetic line absent in Gd2Sn2O7. These low-lying excitations with gaps, which are preformed above the ordering transition, may be interpreted as collective spin modes split by the single-ion anisotropy.
|Item Type:||Journal Article|
|Subjects:||Q Science > QC Physics|
|Divisions:||Faculty of Science > Physics|
|Library of Congress Subject Headings (LCSH):||Nuclear spin, Paramagnetism, Antiferromagnetism, Electron paramagnetic resonance, Spin excitations|
|Journal or Publication Title:||Physical Review B (Condensed Matter and Materials Physics)|
|Publisher:||American Physical Society|
|Official Date:||March 2008|
|Number of Pages:||8|
|Page Range:||Article No. 104424|
|Access rights to Published version:||Restricted or Subscription Access|
|Funder:||International Association for the Promotion of Co-operation with Scientists from the Independent States of the Former Soviet Union (INTAS), Rossiĭskiĭ fond fundamentalʹnykh issledovaniĭ [Russian Foundation of Basic Research] (RFFI), RF President Program|
|Grant number:||YSF 2004-83-3053 (INTAS), 07-02-00725 (RFFI)|
1R. Moessner and J. T. Chalker, Phys. Rev. Lett. 80, 2929 �1998�.
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