Phase separation enhanced magneto-electric coupling in La0.7Ca0.3MnO3/BaTiO3 ultra-thin films

• Published in: Scientific reports Vol. 5; no. 1; p. 17926
• Main Authors: Alberca, A., Munuera, C., Azpeitia, J., Kirby, B., Nemes, N. M., Perez-Muñoz, A. M., Tornos, J., Mompean, F. J., Leon, C., Santamaria, J., Garcia-Hernandez, M.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 09-12-2015; Nature Publishing Group
• Subjects: 639/301/1005/1008; 639/766/119/544; 639/766/119/996; 639/925/930/12; Anisotropy; Electric fields; Humanities and Social Sciences; Metals; multidisciplinary; Science; Thin films
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep17926

We study the origin of the magnetoelectric coupling in manganite films on ferroelectric substrates. We find large magnetoelectric coupling in La
0.7
Ca
0.3
MnO
3
/BaTiO
3
ultra-thin films in experiments based on the converse magnetoelectric effect. The magnetization changes by around 30–40% upon applying electric fields on the order of 1 kV/cm to the BaTiO
3
substrate, corresponding to magnetoelectric coupling constants on the order of α = (2–5)·10
−7
 s/m. Magnetic anisotropy is also affected by the electric field induced strain, resulting in a considerable reduction of coercive fields. We compare the magnetoelectric effect in pre-poled and unpoled BaTiO
3
substrates. Polarized neutron reflectometry reveals a two-layer behavior with a depressed magnetic layer of around 30 Å at the interface. Magnetic force microscopy (MFM) shows a granular magnetic structure of the La
0.7
Ca
0.3
MnO
3
. The magnetic granularity of the La
0.7
Ca
0.3
MnO
3
film and the robust magnetoelastic coupling at the La
0.7
Ca
0.3
MnO
3
/BaTiO
3
interface are at the origin of the large magnetoelectric coupling, which is enhanced by phase separation in the manganite.