Abstract
A detailed elastic neutron scattering study of the structural and magnetic phase transitions in single-crystal SrFe2 As2 reveals that the orthorhombic (O)-tetragonal (T) and the antiferromagnetic transitions coincide at TO = TN = (201.5±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 TO, we suggest that the T-O transition may be an order-disorder transition.
Original language | English |
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Article number | 054407 |
Journal | Physical Review B - Condensed Matter and Materials Physics |
Volume | 80 |
Issue number | 5 |
DOIs | |
State | Published - Aug 13 2009 |
Externally published | Yes |