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

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.

6 pages, 6 figues, including Supplementary

References in corpus (4)

• Dirac Strings and Magnetic Monopoles in Spin Ice Dy2Ti2O7
• Molecular spin resonance in the geometrically frustrated MgCr2O4 magnet by inelastic neutron scattering
• Spin Hamiltonian, {Order Out of a Coulomb Phase} and Pseudo-Criticality in the Highly Frustrated Pyrochlore Heisenberg Antiferromagnet FeF${}_3$}
• Color ice states, weathervane modes, and order by disorder in the bilinear-biquadratic pyrochlore Heisenberg antiferromagnet

Cited by in corpus (2)

• Six-loop $\epsilon$ expansion study of three-dimensional $O(n)\times O(m)$ spin models
• Magnetic Transitions in the Chiral Armchair-Kagome System Mn${}_2$Sb${}_2$O${}_7$