Anisotropic modulation of magnetic properties and the memory effect in a wide-band (011)-Pr0.7Sr0.3MnO3/PMN-PT heterostructure

Ying-Ying Zhao, Jing Wang, Hao Kuang, Feng-Xia Hu, Yao Liu, Rong-Rong Wu, Xi-Xiang Zhang, Ji-Rong Sun, Bao-Gen Shen
2015 Scientific Reports  
Memory effect of electric-field control on magnetic behavior in magnetoelectric composite heterostructures has been a topic of interest for a long time. Although the piezostrain and its transfer across the interface of ferroelectric/ferromagnetic films are known to be important in realizing magnetoelectric coupling, the underlying mechanism for nonvolatile modulation of magnetic behaviors remains a challenge. Here, we report on the electric-field control of magnetic properties in wide-band
more » ... -Pr 0.7 Sr 0.3 MnO 3 /0.7Pb (Mg 1/3 Nb 2/3 )O 3 -0.3PbTiO 3 heterostructures. By introducing an electric-field-induced in-plane anisotropic strain field during the cooling process from room temperature, we observe an in-plane anisotropic, nonvolatile modulation of magnetic properties in a wide-band Pr 0.7 Sr 0.3 MnO 3 film at low temperatures. We attribute this anisotropic memory effect to the preferential seeding and growth of ferromagnetic (FM) domains under the anisotropic strain field. In addition, we find that the anisotropic, nonvolatile modulation of magnetic properties gradually diminishes as the temperature approaches FM transition, indicating that the nonvolatile memory effect is temperature dependent. By taking into account the competition between thermal energy and the potential barrier of the metastable magnetic state induced by the anisotropic strain field, this distinct memory effect is well explained, which provides a promising approach for designing novel electric-writing magnetic memories. W ith the rapid increasing requirements for information storage, developing compact, innovative devices that offer fast, energy-efficient nonvolatile random access memory is becoming a significant and challenging task. To meet this challenge, a new way to control magnetism via electric fields 1-3 , using the converse magnetoelectric (ME) effect, rather than electric currents or magnetic fields, is attracting tremendous attention. Initial research suggests that the top candidates for realizing electric-field control of magnetism are single-phase multiferroic materials with simultaneous magnetic and ferroelectric orders; however, more recent experiments show that these materials have small converse ME effects and are unsuited to practical application 4 . As an alternative, artificial multiphase systems that consist of both ferromagnetic (FM) and ferroelectric (FE) materials are receiving more attention in recent years 1-3 . Coupling of the two ferroic phases suggests that an electric field may be able to control magnetic properties. Previous experimental work has demonstrated that an electric field can control magnetic anisotropy and remnant magnetization by using strain-mediated ME coupling in heterostructures with FM films grown on FE substrates such as epitaxial La 0.67 Sr 0.33 MnO 3 /BiTiO 3 4 , La 2/3 Sr 1/3 MnO 3 /PMN-PT 5 , polycrystalline Ni/PMN-PT, Fe 3 O 4 /PZNPT, CoFe 2 O 4 /PMN-PT, and CoFe/ BiFeO 3 [6] [7] [8] [9] . For the most part, these studies used the linear-converse piezoelectric response to induce changes in magnetic anisotropy and remnant magnetization, which typically return to their initial state once the driving electric field is removed. However, a nonvolatile tuning of the magnetic state by the electric field, namely the memory effect, is required for information storage. Perovskite manganites contain rich physical phenomena: the Jahn-Teller (JT) distortion, double-exchange coupling, metal-insulator transition, and phase separation due to the strong interplay among lattice, charge, spin, and orbital degrees of freedom. Meanwhile, the lattice strain can modulate most of these properties by modifying OPEN SUBJECT AREAS: FERROELECTRICS AND MULTIFERROICS MAGNETIC PROPERTIES AND MATERIALS
doi:10.1038/srep09668 pmid:25909177 pmcid:PMC5386113 fatcat:wugzdz6cdnddnc2xlivblf5p2a