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arXiv · 1204.6323

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

Eric C. Andrade·Matthias Vojta
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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.

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Eric C. Andrade, Matthias Vojta. 2012-08-13. Disorder, cluster spin glass, and hour-glass spectra in striped magnetic insulators. https://doi.org/10.1103/physrevlett.109.147201

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