Molecular spin-orbit excitations in the J_eff = 1/2 frustrated spinel GeCo${}_2$O${}_4$

Abstract

We describe powder and single-crystal inelastic neutron scattering experiments on a spinel-type antiferromagnet GeCo${}_2$O${}_4$, represented by an effective total angular momentum J_eff = 1/2. Several types of non-dispersive short-range magnetic excitations were discovered. The scattering intensity maps in $\vec{Q}$ space are well reproduced by dynamical structure factor analyses using molecular model Hamiltonians. The results of analyses strongly suggest that the molecular excitations below T_N arise from a hidden molecular-singlet ground state, in which ferromagnetic subunits are antiferromagnetically coupled. The quasielastic excitations above T_N are interpreted as its precursor. A combination of frustration and J_eff = 1/2 might induce these quantum phenomena.

7 pages, 4 figures, submitted to Phys. Rev. B

References in corpus (11)

• Novel Jeff = 1/2 Mott State Induced by Relativistic Spin-Orbit Coupling in Sr2IrO4
• Spin-Liquid State in the S = 1/2 Hyperkagome Antiferromagnet Na4Ir3O8
• Quantum spin Hall effect in a transition metal oxide Na2IrO3
• Direct Observation of Quadrupolar Excitons in the Heavy-Fermion Superconductor PrOs${}_4$Sb${}_{12}$
• Molecular spin resonance in the geometrically frustrated MgCr2O4 magnet by inelastic neutron scattering
• Magnetic frustration in the spinel compounds Ge Co_2 O_4 and Ge Ni_2 O_4
• Magnetic order and dynamics of the charge-ordered antiferromagnet La1.5Sr0.5CoO4
• Monte Carlo study of half-magnetization plateau and magnetic phase diagram in pyrochlore antiferromagnetic Heisenberg model
• Doubly degenerate orbital system in honeycomb lattice: implication of orbital state in layered iron oxide
• Dilution Effects in Two-dimensional Quantum Orbital System
• Jahn-Teller Inactivity and Magnetic Frustration in GeCo${}_2$O${}_4$ Probed by Ultrasound Velocity Measurements

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