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arXiv · 2508.03664

Ising spin ladders of orthopyroxene CoGeO$_3$

Pavel A. Maksimov·Andrey F. Gubkin·Alexey V. Ushakov·Alexander I. Kolesnikov·Matthew S. Cook·Michael A. McGuire·Günther J. Redhammer·Andrey Podlesnyak·Sergey V. Streltsov
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Abstract

We present thermodynamic and spectroscopic measurements for an orthopyroxene CoGeO$_3$ with magnetic Co$^{2+}$ ions that form quasi-one-dimensional ladders. We show that non-collinear magnetic order below $T_N$=32 K can be stabilized by a strong local easy-axis anisotropy of $j_\text{eff}=1/2$ moments, which is induced by ligand octahedra distortions. Extraction of a magnetic Hamiltonian from inelastic neutron scattering measurements supports this interpretation and allows us to establish an effective magnetic model. The resulting exchange Hamiltonian justifies CoGeO$_3$ as a realization of an Ising spin ladder compound.

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Pavel A. Maksimov, Andrey F. Gubkin, Alexey V. Ushakov, Alexander I. Kolesnikov, Matthew S. Cook, Michael A. McGuire, Günther J. Redhammer, Andrey Podlesnyak, Sergey V. Streltsov. 2025-08-05. Ising spin ladders of orthopyroxene CoGeO$_3$. https://doi.org/10.1103/fxrl-yr9g

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