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arXiv · 0908.4253

Magnetic and lattice coupling in single-crystal SrFe$_2$As$_2$: A neutron scattering study

Haifeng Li·Wei Tian·Jerel L. Zarestky·Andreas Kreyssig·Ni Ni·Sergey L. Bud'ko·Paul C. Canfield·Alan I. Goldman·Robert J. McQueeney·David Vaknin
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Abstract

A detailed elastic neutron scattering study of the structural and magnetic phase transitions in single-crystal SrFe$_2$As$_2$ reveals that the orthorhombic (O)-tetragonal (T) and the antiferromagnetic transitions coincide at $T_\texttt{O}$ = $T_\texttt{N}$ = (201.5 $\pm$ 0.25) K. The observation of coexisting O-T phases over a finite temperature range at the transition and the sudden onset of the O distortion provide strong evidences that the structural transition is first order. The simultaneous appearance and disappearance within 0.5 K upon cooling and within 0.25 K upon warming, respectively, indicate that the magnetic and structural transitions are intimately coupled. We find that the hysteresis in the transition temperature extends over a 1-2 K range. Based on the observation of a remnant orthorhombic phase at temperatures higher than \emph{T}$_\texttt{O}$, we suggest that the T-O transition may be an order-disorder transition.

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Haifeng Li, Wei Tian, Jerel L. Zarestky, Andreas Kreyssig, Ni Ni, Sergey L. Bud'ko, Paul C. Canfield, Alan I. Goldman, Robert J. McQueeney, David Vaknin. 2009-08-28. Magnetic and lattice coupling in single-crystal SrFe$_2$As$_2$: A neutron scattering study. https://doi.org/10.1103/physrevb.80.054407

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