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arXiv · 1306.4377

Measurement of the elastoresistivity coefficients of the underdoped iron-arsenide Ba(Fe$_{0.975}$Co$_{0.025}$)$_2$As$_2$

Hsueh-Hui Kuo·Maxwell C. Shapiro·Scott C. Riggs·Ian R. Fisher
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Abstract

A new method is presented for measuring terms in the elastoresistivity tensor $m_{ij}$ of single crystal samples with tetragonal symmetry. The technique is applied to a representative underdoped Fe-arsenide, Ba(Fe$_{0.975}$Co$_{0.025}$)$_2$As$_2$, revealing an anomalously large and anisotropic elastoresistance in comparison to simple metals. The $m_{66}$ coefficient follows a Curie-Weiss temperature dependence, providing direct evidence that the tetragonal-to-orthorhombic structural phase transition that occurs at $T_s$ = 97.5 K in this material is not the result of a true-proper ferro-elastic transition. Rather, the material suffers a pseudo-proper transition for which the lattice strain is not the primary order parameter.

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Hsueh-Hui Kuo, Maxwell C. Shapiro, Scott C. Riggs, Ian R. Fisher. 2013-06-18. Measurement of the elastoresistivity coefficients of the underdoped iron-arsenide Ba(Fe$_{0.975}$Co$_{0.025}$)$_2$As$_2$. https://doi.org/10.1103/physrevb.88.085113

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