Discovery of new magnetic orders on pyrochlore spinels

Abstract

Frustration in spin system can give rise to unique ordered states and as a consequence several physical phenomena are expected such as multiferroics, high temperature superconductors and anomalous hall effect. Here we report the "new magnetic orders" induced by anisotropic spin exchanges on pyrochlore spinels as the interplay of spin orbit coupling and geometrical frustration. Due to complicated superexchange paths of B-site spinels, we claim that anisotropic interaction between next-nearest neighbors play an important role. Based on the systematic studies of generic spin model, we argue that several classical spin states can be explored in spinel systems; local XY state, all-in all-out state, Palmer-Chalker state and coplanar spiral state. In addition, we reveal new types of magnetic phases with finite ordering wavevectors, labeled as 'octagonal (prism)' state and '(distorted) cubic' states. When the 'octagonal prism' state is stabilized, non-zero scalar spin chirality induces alternating net current in addition to finite orbital current and orbital magnetization even in Mott insulators. Finally, we also discuss the relevance of 'distorted cubic' state to the magnetic order of spinel compound GeCo2O4.

10 pages, 8 figures

References in corpus (10)

• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Definitive Evidence for Order-by-Quantum-Disorder in Er2Ti2O7
• Electronic Orbital Currents and Polarization in Mott Insulators
• Spin-orbit effects in Na${}_4$Ir${}_3$O${}_8$, a hyper-kagomé lattice antiferromagnet
• Quasiparticle Breakdown and Spin Hamiltonian of the Frustrated Quantum Pyrochlore Yb${}_2$Ti${}_2$O${}_7$ in Magnetic Field
• Noncoplanar magnetic ordering driven by itinerant electrons on the pyrochlore lattice
• Magnetic frustration in the spinel compounds Ge Co_2 O_4 and Ge Ni_2 O_4
• Structural distortion below the Néel temperature in spinel GeCo${}_2$O${}_4$
• Pseudo-Goldstone magnons in the frustrated S=3/2 Heisenberg helimagnet ZnCr2Se4 with a pyrochlore magnetic sublattice
• Field driven magnetostructural transitions in GeCo${}_2$O${}_4$

Cited by in corpus (3)

• Ordered ground states of kagome magnets with generic exchange anisotropy
• Theory of transverse magnetization in spin-orbit coupled antiferromagnets
• Quantum spin models of commensurate $p$-wave magnets