Disorder, cluster spin glass, and hour-glass spectra in striped magnetic insulators

Abstract

Hour-glass-shaped magnetic excitation spectra have been detected in a variety of doped transition-metal oxides with stripe-like charge order. Compared to the predictions of spin-wave theory, these spectra display a different intensity distribution and anomalous broadening. Here we show, based on a comprehensive modelling of these phenomena for La5/3Sr1/3CoO4, how quenched disorder in the charge sector causes frustration, and consequently cluster-glass behavior at low temperatures, in the spin sector. This spin-glass physics, which is insensitive to the detailed nature of the charge disorder, but sensitive to the relative strength of the magnetic inter-stripe coupling, ultimately determines the distribution of magnetic spectral weight and thus causes the hour-glass spectrum.

5 pages, 4 figures. Supplemental Material: 8 pages, 10 figures. Explicit comparison to experimental results in La5/3Sr1/3CoO4 included

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Cited by in corpus (4)

• Hour-glass magnetic excitations induced by nanoscopic phase separation in cobalt oxides La${}_{2-x}$Sr${}_x$CoO${}_4$
• Diversity of charge orderings in correlated systems
• Energy-dependent crossover from anisotropic to isotropic magnetic dispersion in lightly-doped La1.96Sr0.04CuO4
• Quantum Spin Liquids Stabilized by Disorder in Non-Kramers Pyrochlores