Neutron Study of the Magnetic Structures and Phase Transitions in RCuAs$_2$ (R=Pr, Nd, Tb, Dy, Ho, Yb)

ORAL

Abstract

Neutron diffraction and inelastic scattering studies have been carried out on polycrystalline samples of the above titled materials as a function of temperature and applied magnetic field to determine the magnetic structures, order parameters, and overall spin dynamics. The space group of these compound is P4/nmm with typical (tetragonal) lattice parameters a $\sim$ 3.9 \AA\ and c $\sim$ 10.0 \AA. PrCuAs$_{2}$ develops commensurate magnetic order at T$_{N}$=6.4 K with an ordered moment of 1.24 $\mu _{B}$ oriented along the c-axis. The ordering wave vector is (0,0,1/2), with a $\Gamma _{3}^{1}$ representation. NdCuAs$_{2}$ orders at T$_{N}$=3.54 K with the same ordering wave vector (with the $\Gamma _{10}^{2}$ or $\Gamma _{9}^{2}$ representations), but with the moment direction in the a-b plane along [110] of magnitude 3.5 $\mu _{B}$. TbCuAs$_{2}$ and HoCuAs$_{2}$ exhibit incommensurate order at T$_{N}$=9.1 and 4.0 K, respectively. The results for the inelastic scattering will be discussed.

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Authors

  • Yang Zhao

    • NIST Center for Neutron Research, National Institute of Standards and Technology, USA
    • Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA
    • National Institute of Standards and Technology

  • J. W. Lynn

    • Center for Neutron Research, NIST
    • NIST Center for Neutron Research
    • NIST Center for Neutron Research, Gaithersburg, Maryland, 20899, USA

  • Gohil S. Thakur

    • Department of Chemistry, Indian Institute of Technology Delhi, India

  • Zeba Haque

    • Department of Chemistry, Indian Institute of Technology Delhi, India

  • L.C. Gupta

    • Department of Chemistry, Indian Institute of Technology Delhi, India

  • A.K. Ganguli

    • Department of Chemistry, Indian Institute of Technology Delhi, India