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Title: Transport thermal properties of LiTaO 3 pyroelectric sensor from 15 K to 400 K and its application to the study of critical behavior in EuCo 2As 2

ac photopyroelectric calorimeters in the standard back configuration, where LiTaO 3 is one of the most popular materials to be used as a detector, are commonly used to study phase transitions in solids and liquids. In order to extract the specific heat of a studied sample, a good knowledge of the thermal effusivity of the sensor as a function of temperature is needed. This function has been obtained for the first time in the range 15 K to 400 K by independently measuring LiTaO 3 thermal diffusivity and specific heat and combining both of them to give thermal effusivity. Using this photopyroelectric setup and LiTaO 3 as sensor, we have carried out the study of the critical behavior of the antiferromagnetic ordering of the Eu 2+ spins in EuCo 2As 2 (a compound with similar structure as EuFe 2As 2, from which superconductors have been developed) at low temperature by measuring its specific heat. Furthermore, the critical parameters found for EuCo 2As 2 (α=–0.017,A +/A =1.06) agree with the 3D-XY universality class, indicating that the spins present an in-plane arrangement for Eu 2+, in agreement with magnetic measurements in the literature.
Authors:
 [1] ;  [2] ;  [3] ;  [1]
  1. Univ. del Pais Vasco UPV/EHU, Bilbao (Spain)
  2. Univ. del Pais Vasco UPV/EHU, Bilbao (Spain); Uzhgorod Univ., Uzhgorod (Ukraine)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
International Journal of Thermophysics
Additional Journal Information:
Journal Volume: 37; Journal Issue: 1; Journal ID: ISSN 0195-928X
Publisher:
Springer
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION; critical behavior; EuFe2As2; LiTaO3; photopyroelectric calorimeter; thermal effusivity
OSTI Identifier:
1267058