Pressure Effect on the Structural and Magnetic Transition in CaFe$_2$As$_2$

ORAL

Abstract

We use neutron scattering technique to study both the structural and magnetic phase transitions of CaFe$_2$As$_2$. We confirmed that the nuclear structure changes from orthorhombic to collapsed tetragonal phase with increasing pressure at low temperatures. Strong hysteresis is found in increasing and decreasing temperature processes. The c-axis lattice constant of the orthorhombic phase is found to increase with deceasing temperature under pressure while that of the collapsed tetragonal phase shows almost no change, which suggests a strong magnetic-lattice coupling.

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Authors

  • Shiliang Li

    Department of Physics and Astronomy, The University of Tennessee, University of Tennessee, Knoxville, University of Tennessee

  • Ying Chen

    NCNR and Univ. of Maryland, NIST Center for Neutron Research, National Institute of Standards and Technology, NIST Center for Neutron Research, University of Maryland

  • Jeffrey Lynn

    NIST Center for Neutron Research

  • X. H. Chen

    University of Science and Technology, USTC

  • Pengcheng Dai

    Oak Ridge National Laboratory, Univ of Tennessee, Knoxville, University of Tennessee, Knoxville, Univ. of Tennessee and NSSD-ORNL, University of Tennessee, Oak Ridge National Laboratory