Simultaneous measurement of pressure evolution of crystal structure and superconductivity in FeSe[subscript 0.92] using designer diamonds

Journal Article · Wed Apr 19 04:00:00 EDT 2017 · Europhysics Letters

DOI:https://doi.org/10.1209/0295-5075/99/26002· OSTI ID:1047304

Uhoya, Walter; Tsoi, Georgiy; Vohra, Yogesh; Wolanyk, Nathaniel; Rao, Sistla Muralidhara; Wu, Maw-Kuen; Weir, Samuel ^[1]

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1. LLNL

Simultaneous high-pressure X-ray diffraction and electrical resistance measurements have been carried out on a PbO-type {alpha}-FeSe{sub 0.92} compound to a pressure of 44 GPa and temperatures down to 4 K using designer diamond anvils at synchrotron source. A ambient temperature, a structural phase transition from a tetragonal (P4/nmm) phase to an orthorhombic (Pbnm) phase is observed at 11 GPa and the Pbnm phase persists up to 74 GPa. The superconducting transition temperature (T{sub c}) increases rapidly with pressure reaching a maximum of {approx}28 K at {approx}6 GPa and decreases at higher pressures, disappearing completely at 14.6 GPa. Simultaneous pressure-dependent X-ray diffraction and resistance measurements at low temperatures show superconductivity only in a low-pressure orthorhombic (Cmma) phase of the {alpha}-FeSe{sub 0.92}. Upon increasing pressure at 10 K near T{sub c}, crystalline phases change from a mixture of orthorhombic (Cmma) and hexagonal (P63/mmc) phases to a high-pressure orthorhombic (Pbnm) phase near 6.4 GPa where T{sub c} is maximum.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: DOE - OTHERNSF
• OSTI ID: 1047304
• Journal Information: Europhysics Letters, Journal Name: Europhysics Letters Journal Issue: (2) ; 07, 2012 Vol. 99; ISSN 0295-5075
• Country of Publication: United States
• Language: ENGLISH