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arXiv · 1408.6666

Persistent detwinning of iron pnictides by small magnetic fields

S. Zapf·C. Stingl·K. W. Post·J. Maiwald·N. Bach·I. Pietsch·D. Neubauer·A. Loehle·C. Clauss·S. Jiang·H. S. Jeevan·D. N. Basov·P. Gegenwart·M. Dressel
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Abstract

Our comprehensive study on EuFe$_2$As$_2$ reveals a dramatic reduction of magnetic detwinning fields compared to other AFe$_2$As$_2$ (A = Ba, Sr, Ca) iron pnictides by indirect magneto-elastic coupling of the Eu$^{2+}$ ions. We find that only 0.1T are sufficient for persistent detwinning below the local Eu$^{2+}$ ordering; above $T_\text{Eu}$ = 19K, higher fields are necessary. Even after the field is switched off, a significant imbalance of twin domains remains constant up to the structural and electronic phase transition (190K). This persistent detwinning provides the unique possibility to study the low temperature electronic in-plane anisotropy of iron pnictides without applying any symmetrybreaking external force.

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S. Zapf, C. Stingl, K. W. Post, J. Maiwald, N. Bach, I. Pietsch, D. Neubauer, A. Loehle, C. Clauss, S. Jiang, H. S. Jeevan, D. N. Basov, P. Gegenwart, M. Dressel. 2014-08-28. Persistent detwinning of iron pnictides by small magnetic fields. https://doi.org/10.1103/physrevlett.113.227001

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