Magnetic properties of La_0.7Sr_0.3MnO₃ under the pressure and the transport property under the magnetic field

Abstract

Polycrystalline La 0.7 Sr 0.3 MnO 3 sample (LSMO) was synthesized by the solid phase reaction; it exhibits the paramagnetic-ferromagnetic transition at T c = 362 K at the ambient pressure; it is paramagnetic metallic state above T c and the ferromagnetic metallic state below T c. It was observed that the pressure effect depends on the temperature range: (a) In the paramagnetic region, the magnetization M hardly changes with the pressure P, that is, ΔM≈0. There exist the antiferromagnetic (AFM) coupled ferromagnetic clusters in the paramagnetic region, and the pressure enhances the AFM coupling. (b) In the temperature range around T c , the pressure increases M, that is, ΔM > 0, with the concomitant increase in T c ; the average pressure coefficient dT c /dP is 5.40 K/GPa at P = .74 GPa, much smaller than 15.47 and 15.90 K/GPa for La 0.7 Ca 0.3 MnO 3 and La 0.9 Ca 0.1 MnO 3 , respectively, due to the different distortion degree of MnO 6 octahedra in Ca and Sr doped manganites. (c) In the temperature region below T c , the pressure reduces M, that is, ΔM < 0. M is determined by the competition between the Mn 3+-O-Mn 4+ double exchange and the interparticle dipolar interaction. The pressure enhances the interparticle dipolar interaction, leading to a significant decrease in magnetization. The resistivity of LSMO exhibits the metallic behavior in the temperature range of 5 K~370 K; it decreases as the applied magnetic field H increases from 0 to 7 T, that is, the magnetoresistance effect which is more significant around T c. The fitting to the low-temperature resistivity shows that the applied magnetic field reduces the scattering from the grain boundary, electron, phonon, and magnon, especially reduces the electron-electron scattering. K E Y W O R D S double exchange, Jahn-Teller distortion, La 0.7 Sr 0.3 MnO 3 , magnetic properties, pressure How to cite this article: Zhang X, Han Y, Kan X, et al. Magnetic properties of La 0.7 Sr 0.3 MnO 3 under the pressure and the transport property under the magnetic field.

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Polarization current effect, strain effect and ferroelectric field effect on electrical transport properties of Eu0.7Sr0.3MnO3/PMN-PT multiferroic heterostructure

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