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Structural and Magnetic Instabilities of La$_{2-x}$Sr$_x$CaCu$_2$O$_6$

C. Ulrich·S. Kondo·M. Reehuis·H. He·C. Bernhard·C. Niedermayer·F. Bouree·P. Bourges·M. Ohl·H. M. Ronnow·H. Takagi·B. Keimer
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Abstract

A neutron scattering study of nonsuperconducting La$_{2-x}$Sr$_x$CaCu$_2$O$_6$ (x=0 and 0.2), a bilayer copper oxide without CuO chains, has revealed an unexpected tetragonal-to-orthorhombic transition with a doping dependent transition temperature. The predominant structural modification below the transition is an in-plane shift of the apical oxygen. In the doped sample, the orthorhombic superstructure is strongly disordered, and a glassy state involving both magnetic and structural degrees of freedom develops at low temperature. The spin correlations are commensurate.

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C. Ulrich, S. Kondo, M. Reehuis, H. He, C. Bernhard, C. Niedermayer, F. Bouree, P. Bourges, M. Ohl, H. M. Ronnow, H. Takagi, B. Keimer. 2002-06-03. Structural and Magnetic Instabilities of La$_{2-x}$Sr$_x$CaCu$_2$O$_6$. https://doi.org/10.1103/physrevb.65.220507

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