Magnon specific heat of CuGeO3 in the spin-Peierls state

Y. K. Kuo; D. K. Powell; J. W. Brill

doi:10.1016/0038-1098(96)00177-9

Magnon specific heat of CuGeO₃ in the spin-Peierls state

Y. K. Kuo, D. K. Powell, J. W. Brill

Research output: Contribution to journal › Article › peer-review

6 Scopus citations

Abstract

We have used ac calorimetry to measure the specific heat of CuGeO₃ below its spin-Peierls transition temperature in magnetic fields up to 7T, and have compared it to values calculated from a model triplet magnon dispersion curve. We find that the observed field dependence is much smaller than that calculated with Zeeman splitting of the magnon gap, but is consistent with that calculated assuming m=0 excitation (and mean-field, quadratic magnetic field dependence) only. This result implies weak coupling between thermal phonons and m=±1 magnons, so that population of the latter are frozen for times < 40 ms. A similar assumption accounts for the zero-field specific heat at temperatures above 4.5 K.

Original language	English
Pages (from-to)	1027-1031
Number of pages	5
Journal	Solid State Communications
Volume	98
Issue number	11
DOIs	https://doi.org/10.1016/0038-1098(96)00177-9
State	Published - Jun 1996

Bibliographical note

Funding Information:
AcknowledgmentW-e thankL .E. DeLong for use of the magnet,C .P. Brock for x-ray analysis, H. Fertig for helpful discussions, and Lake-Shore Cryotronics for supplyingt heb olometers.T his researchw as supportedin part by the U.S. National Science Foundation, grants #DMR-930050a7n d EHR-9108764.

Keywords

A. Magnetically ordered materials
D. Heat capacity
D. Phase transitions

ASJC Scopus subject areas

General Chemistry
Condensed Matter Physics
Materials Chemistry

Access to Document

10.1016/0038-1098(96)00177-9

Cite this

@article{214a9e090e0f4170aa9d459fc295cdb5,

title = "Magnon specific heat of CuGeO3 in the spin-Peierls state",

abstract = "We have used ac calorimetry to measure the specific heat of CuGeO3 below its spin-Peierls transition temperature in magnetic fields up to 7T, and have compared it to values calculated from a model triplet magnon dispersion curve. We find that the observed field dependence is much smaller than that calculated with Zeeman splitting of the magnon gap, but is consistent with that calculated assuming m=0 excitation (and mean-field, quadratic magnetic field dependence) only. This result implies weak coupling between thermal phonons and m=±1 magnons, so that population of the latter are frozen for times < 40 ms. A similar assumption accounts for the zero-field specific heat at temperatures above 4.5 K.",

keywords = "A. Magnetically ordered materials, D. Heat capacity, D. Phase transitions",

author = "Kuo, {Y. K.} and Powell, {D. K.} and Brill, {J. W.}",

note = "Funding Information: AcknowledgmentW-e thankL .E. DeLong for use of the magnet,C .P. Brock for x-ray analysis, H. Fertig for helpful discussions, and Lake-Shore Cryotronics for supplyingt heb olometers.T his researchw as supportedin part by the U.S. National Science Foundation, grants #DMR-930050a7n d EHR-9108764.",

year = "1996",

month = jun,

doi = "10.1016/0038-1098(96)00177-9",

language = "English",

volume = "98",

pages = "1027--1031",

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TY - JOUR

T1 - Magnon specific heat of CuGeO3 in the spin-Peierls state

AU - Kuo, Y. K.

AU - Powell, D. K.

AU - Brill, J. W.

N1 - Funding Information: AcknowledgmentW-e thankL .E. DeLong for use of the magnet,C .P. Brock for x-ray analysis, H. Fertig for helpful discussions, and Lake-Shore Cryotronics for supplyingt heb olometers.T his researchw as supportedin part by the U.S. National Science Foundation, grants #DMR-930050a7n d EHR-9108764.

PY - 1996/6

Y1 - 1996/6

N2 - We have used ac calorimetry to measure the specific heat of CuGeO3 below its spin-Peierls transition temperature in magnetic fields up to 7T, and have compared it to values calculated from a model triplet magnon dispersion curve. We find that the observed field dependence is much smaller than that calculated with Zeeman splitting of the magnon gap, but is consistent with that calculated assuming m=0 excitation (and mean-field, quadratic magnetic field dependence) only. This result implies weak coupling between thermal phonons and m=±1 magnons, so that population of the latter are frozen for times < 40 ms. A similar assumption accounts for the zero-field specific heat at temperatures above 4.5 K.

AB - We have used ac calorimetry to measure the specific heat of CuGeO3 below its spin-Peierls transition temperature in magnetic fields up to 7T, and have compared it to values calculated from a model triplet magnon dispersion curve. We find that the observed field dependence is much smaller than that calculated with Zeeman splitting of the magnon gap, but is consistent with that calculated assuming m=0 excitation (and mean-field, quadratic magnetic field dependence) only. This result implies weak coupling between thermal phonons and m=±1 magnons, so that population of the latter are frozen for times < 40 ms. A similar assumption accounts for the zero-field specific heat at temperatures above 4.5 K.

KW - A. Magnetically ordered materials

KW - D. Heat capacity

KW - D. Phase transitions

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