Anisotropic thermal expansion of AEFe(2)As(2) (AE = Ba, Sr, Ca) single crystals

Date
2010-03-21
Authors
Bud’ko, Sergey
Ni, Ni
Canfield, Paul
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Ames Laboratory
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Physics and Astronomy
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Abstract

We report anisotropic thermal expansion of the parent, AEFe2As2 (AE = Ba, Sr, and Ca), compounds. Above the structural/antiferromagnetic phase transition anisotropy of the thermal expansion coefficients is observed, with the coefficient along the a-axis being significantly smaller than the coefficient for the c-axis. The high temperature (200 K ≤ T ≤ 300 K) coefficients themselves have similar values for the compounds studied. The sharp anomalies associated with the structural/antiferromagnetic phase transitions are clearly seen in the thermal expansion measurements. For all three pure compounds, the ‘average’ a-value increases and the c-lattice parameter decreases on warming through the transition, with the smallest change in the lattice parameters observed for SrFe2As2. The data are in general agreement with the literature data from X-ray and neutron diffraction experiments.

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This article was published by Taylor & Francis as Bud'ko, Sergey L., Ni Ni, and Paul C. Canfield. "Anisotropic thermal expansion of AE Fe2As2 (AE= Ba, Sr, Ca) single crystals." Philosophical Magazine 90, no. 9 (2010): 1219-1227. DOI: 10.1080/14786430903325041.

Keywords
iron-arsenides, thermal expansion, anisotropy, structural phase transition
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