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Magneto-Elastic Coupling in the Layered Manganite La$_{1.2}$Sr$_{1.8}$Mn$_2$O$_7$

C. N. Brosseau·M. Poirier·R. Suryanarayanan·G. Dhalenne·A. Revcolevschi
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Abstract

We have studied the magneto-elastic coupling in the double layered Mn perovskite La$_{1.2}$Sr$_{1.8}$Mn$_2$O$_7$ with an ultrasonic velocity technique. The temperature profile of both the in-plane and out-of-plane longitudinal velocities showed a large stiffening anomaly below the insulating paramagnetic to metallic ferromagnetic transition. Magnetic fluctuations effects consistent with the layered structure are evidenced as a frequency dependent velocity softening above the transition. The magneto-elastic coupling has been studied in magnetic field values up to 8 Tesla: the observations are consistent with a substantial magnetic anisotropy and a ferromagnetic order parameter with moments lying in the layers.

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C. N. Brosseau, M. Poirier, R. Suryanarayanan, G. Dhalenne, A. Revcolevschi. 2000-12-20. Magneto-Elastic Coupling in the Layered Manganite La$_{1.2}$Sr$_{1.8}$Mn$_2$O$_7$. https://arxiv.org/abs/cond-mat/0012380

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