Thermal expansion, phase diagrams and barocaloric effects in (NH(4))(2)NbOF(5).
J Phys Condens Matter
; 22(18): 185901, 2010 May 12.
Article
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| MEDLINE
| ID: mdl-21393694
The thermal expansion along the a, b and c axes of a (NH(4))(2)NbOF(5) crystal was measured from 120 to 300 K. Anomalies of α(T) associated with previously reported phase transitions Cmc2(1) --> C2 --> 1a were observed along all directions at T(1) = 259.3 K and T(2) = 220.5 K. The analysis of thermal expansion and heat capacity in the frame of the Pippard relations has permitted us to determine the uniaxial pressure derivatives of the transition temperatures dT/dσ(i). The T-σ(i) phase diagrams have shown a tendency for the intermediate phase to disappear at high stress along the b and c axes. Intensive and extensive barocaloric effects near the structural phase transitions were found to be comparable with the caloric parameters of some ferroelectrics, ferromagnets and antiferromagnets.
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01-internacional
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MEDLINE
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En
Revista:
J Phys Condens Matter
Asunto de la revista:
BIOFISICA
Año:
2010
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Article
País de afiliación:
Rusia
Pais de publicación:
Reino Unido