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Specific heat and magnetic order in LaMnO_{3+δ}

L. Ghivelder·I. Abrego Castillo·M. A. Gusmao·J. A. Alonso·L. F. Cohen
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Abstract

Magnetic and specific-heat measurements are performed in three different samples of LaMnO_{3+δ}, with δ=0.11, 0.15 and 0.26, presenting important disorder effects, such as carrier localization, due to high amounts of La and Mn vacancies. For the samples with δ=0.11 and 0.15, magnetic measurements show signatures of a two-step transition: as the temperature is lowered, the system enters a ferromagnetic phase followed by a disorder-induced cluster-glass state. Spin-wave-like contributions and an unexpected large linear term are observed in the specific heat as a function of temperature. In the sample with the highest vacancy content, δ=0.26, the disorder is sufficient to suppress even short-range ferromagnetic order and yield a spin-glass-like state.

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L. Ghivelder, I. Abrego Castillo, M. A. Gusmao, J. A. Alonso, L. F. Cohen. 1999-04-16. Specific heat and magnetic order in LaMnO_{3+δ}. https://doi.org/10.1103/physrevb.60.12184

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