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Anisotropic superexchange of a 90 degree Cu-O-Cu bond

V. Yu. Yushankhai·R. Hayn
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Abstract

The magnetic anisotropy af a rectangular Cu-O-Cu bond is investigated in second order of the spin-orbit interaction. Such a bond is characteristic for cuprates having edge sharing CuO_2 chains, and exists also in the Cu_3O_4 plane or in ladder compounds. For a ferromagnetic coupling between the copper spins an easy axis is found perpendicular to the copper oxygen plaquettes in agreement with the experimental spin structure of Li_2CuO_2. In addition, a pseudo-dipolar interaction is derived. Its estimation in the case of the Cu_3O_4 plane (which is present for instance in Ba_2Cu_3O_4Cl_2 or Sr_2Cu_3O_4Cl_2) gives a value which is however two orders of magnitude smaller than the usual dipole-dipole interaction.

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V. Yu. Yushankhai, R. Hayn. 1999-03-01. Anisotropic superexchange of a 90 degree Cu-O-Cu bond. https://doi.org/10.1209/epl%2Fi1999-00360-9

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