Independent Control of the Magnetization in Ferromagnetic La sub(2/3)Sr sub(1/3)MnO sub(3)/SrTiO sub(3)/L aCoO sub(3) Heterostructures Achieved by Epitaxial Lattice Mismatch

• Published in: Nano letters Vol. 16; no. 3; pp. 1736 - 1740
• Main Authors: Rivas-Murias, Beatriz, Lucas, Irene, Jimenez-Cavero, Pilar, Magen, Cesar, Morellon, Luis, Rivadulla, Francisco
• Format: Journal Article
• Language: English
• Published: 09.03.2016
• Subjects: Epitaxy; Ferromagnetism; Lattices; Magnetic properties; Magnetization; Strain; Strontium titanates; Thin films
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.5b04657

We report the effect of interface symmetry-mismatch on the magnetic properties of LaCoO sub(3) (LCO) thin films. Growing epitaxial LCO under tensile strain on top of cubic SrTiO sub(3) (STO) produces a contraction along the c axis and a characteristic ferromagnetic response. However, we report here that ferromagnetism in LCO is completely suppressed when grown on top of a buffer layer of rhombohedral La sub(2/3)Sr sub(1/3)MnO sub(3) (LSMO), in spite of identical in-plane and out-of-plane lattice deformation. This confirms that it is the lattice symmetry mismatch and not just the total strain, which determines the magnetism of LCO. On the basis of this control over the magnetic properties of LCO, we designed a multilayered structure to achieve independent rotation of the magnetization in ferromagnetic insulating LCO and half-metallic ferromagnet LSMO. This is an important step forward for the design of spin-filtering tunnel barriers based on LCO. Keywords: LaCoO sub(3); ferromagnetic-insulator; spin-filter tunnel junction; thin-film; epitaxial multilayers; exchange-bias