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Crystal structure and high-field magnetism of La2CuO4

M. Reehuis·C. Ulrich·K. Prokes·A. Gozar·G. Blumberg·Seiki Komiya·Yoichi Ando·P. Pattison·B. Keimer
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Abstract

Neutron diffraction was used to determine the crystal structure and magnetic ordering pattern of a La2CuO4 single crystal, with and without applied magnetic field. A previously unreported, subtle monoclinic distortion of the crystal structure away from the orthorhombic space group Bmab was detected. The distortion is also present in lightly Sr-doped crystals. A refinement of the crystal structure shows that the deviation from orthorhombic symmetry is predominantly determined by displacements of the apical oxygen atoms. An in-plane magnetic field is observed to drive a continuous reorientation of the copper spins from the orthorhombic b-axis to the c-axis, directly confirming predictions based on prior magnetoresistance and Raman scattering experiments. A spin-flop transition induced by a c-axis oriented field previously reported for non-stoichiometric La2CuO4 is also observed, but the transition field (11.5 T) is significantly larger than that in the previous work.

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M. Reehuis, C. Ulrich, K. Prokes, A. Gozar, G. Blumberg, Seiki Komiya, Yoichi Ando, P. Pattison, B. Keimer. 2006-01-26. Crystal structure and high-field magnetism of La2CuO4. https://doi.org/10.1103/physrevb.73.144513

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