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arXiv · 1611.02811

The $3d$-Electron Heisenberg Pyrochlore Mn$_2$Sb$_2$O$_7$

Darren C. Peets·Hasung Sim·Maxim Avdeev·Je-Geun Park
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Abstract

In frustrated magnetic systems, geometric constraints or the competition amongst interactions introduce extremely high degeneracy and prevent the system from readily selecting a low-temperature ground state. The most frustrated known spin arrangement is on the pyrochlore lattice, but nearly all magnetic pyrochlores have unquenched orbital angular momentum, constraining the spin directions through spin-orbit coupling. Pyrochlore Mn$_2$Sb$_2$O$_7$ is an extremely rare Heisenberg pyrochlore system, with directionally-unconstrained spins and low chemical disorder. We show that it undergoes a spin-glass transition at 5.5K, which is suppressed by disorder arising from Mn vacancies, indicating this ground state to be a direct consequence of the spins' interactions. The striking similarities to $3d$ transition metal pyrochlores with unquenched angular momentum suggests that the low spin-orbit coupling in the $3d$ block makes Heisenberg pyrochlores far more accessible than previously imagined.

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Darren C. Peets, Hasung Sim, Maxim Avdeev, Je-Geun Park. 2016-11-09. The $3d$-Electron Heisenberg Pyrochlore Mn$_2$Sb$_2$O$_7$. https://doi.org/10.1103/physrevb.94.174431

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