Dielectric Relaxation Behavior of BTO/LSMO Heterojunction.

Guoqiang Song,Xiaodong Tang,Wei Bai,Yuanyuan Zhang,Jing Yang,Sheng Li

doi:10.3390/nano11051109

Guoqiang Song, Xiaodong Tang + Show 4 more

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https://doi.org/10.3390/nano11051109

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Abstract

The BaTiO3 (BTO)/La0.7Sr0.3MnO3 (LSMO) magnetoelectric composite films were prepared by sol-gel method on STO (001) substrates. The heterojunction has highly preferred orientation and exhibits well ferroelectric properties with perfect hysteresis loops and microscopic polarization switch behaviors. The most interesting thing is the abnormal dielectric relaxation phenomenon in the dielectric spectra at high frequency range and around the phase transition temperature of LSMO. By analyzing the resistance properties of LSMO films, it is indicated that charge-based interfacial coupling, Maxwell-Wagner effect due to the JT polaron and fast resistivity rise in LSMO layer is the main reason. This work emphasizes the crucial role of resistivity exchanges and of carrier accumulation at interfaces for the application of magnetoelectric heterojunction.

Highlights

The multiferroic heterojunction composed of single-phase ferroelectric (FE) materials and ferromagnetic (FM) materials has great potential applications in next-generation information processing and storage devices, such as memory computer read heads, sensors, and multi-state memories [1,2,3,4]
By analyzing the activation energy and the electrical transport properties of La0.7 Sr0.3 MnO3 (LSMO), it is proved that the dielectric relaxation phenomenon is closely related to the MW effect of LSMO thin films
(a = 0.3993nm), it is found that the out of plane strain of LSMO thin films is 0.4%, while the lattice constant of BTO film is almost constant, indicating that it is almost relaxation

Summary

Introduction

The multiferroic heterojunction composed of single-phase ferroelectric (FE) materials and ferromagnetic (FM) materials has great potential applications in next-generation information processing and storage devices, such as memory computer read heads, sensors, and multi-state memories [1,2,3,4]. A number of theoretical and experimental studies attributed magnetoelectric coupling to the interplay between changes in magnetization and accumulation/depletion states at the ferroelectric-ferromagnetic interfaces. It is experimental proved that the magnetoelectric coupling in BTO/doped-manganite heterojunctions can be regulated by the external electric and magnetic field [10,11,12,13]. It is speculated that the physical properties especially the dielectric properties in BTO/doped-manganite heterojunction can be tuned by the temperature dependent self-owned phase transition in manganite. Nanomaterials 2021, 11, 1109 manganite La1−x Ax MnO3 (A = Ca, Sr, or Ba), which is strongly correlated system with perovskite structure, has a strong interplay between electron transport, magnetism, and crystal lattice distortions and a rich carrier-density-temperature phase diagram. By analyzing the activation energy and the electrical transport properties of LSMO, it is proved that the dielectric relaxation phenomenon is closely related to the MW effect of LSMO thin films

Materials and Methods

Results and Discussion

The shape of

Conclusions