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

作者：Bud'ko Sergey L^*; Ni Ni; Canfield Paul C

来源：Philosophical Magazine, 2010, 90(9): 1219-1227.

DOI：10.1080/14786430903325041

• iron-arsenides
• thermal expansion
• anisotropy
• structural phase transition

We report anisotropic thermal expansion of the parent, AEFe(2)As(2) (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 (200K <= 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.

• 出版日期2010