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arXiv · 1512.04448

Magnetic critical properties and basal-plane anisotropy of Sr$_2$IrO$_4$

L. Fruchter·D. Colson·V. Brouet
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Abstract

The anisotropic magnetic properties of Sr$_2$IrO$_4$ are investigated, using longitudinal and torque magnetometry. The critical scaling across $T_c$ of the longitudinal magnetization is the one expected for the 2D XY universality class. Modeling the torque for a magnetic field in the basal-plane, and taking into account all in-plane and out-of-plane magnetic couplings, we derive the effective 4-fold anisotropy $K_4 \approx$ 1 10$^5$ erg mole$^{-1}$. Although larger than for the cuprates, it is found too small to account for a significant departure from the isotropic 2D XY model. The in-plane torque also allows us to put an upper bound for the anisotropy of a field-induced shift of the antiferromagnetic ordering temperature.

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L. Fruchter, D. Colson, V. Brouet. 2015-12-14. Magnetic critical properties and basal-plane anisotropy of Sr$_2$IrO$_4$. https://doi.org/10.1088/0953-8984%2F28%2F12%2F126003

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