Strain-control of local magnetism in manganite films on barium titanate substrates

CIC nanoGUNE Seminars

Dr. Xavier Moya, Universidad de Barcelona
nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian
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Strain-control of local magnetism in manganite films on barium titanate substrates **Host** : Luis Hueso The local magnetic properties of ferromagnetic manganite films grown epitaxially on ferroelectric BaTiO3 substrates can be controlled either electrically1,2 via strain, or magnetically3 via strain‑mediated feedback. The resulting magnetoelectric and magnetocaloric effects depend dramatically on the strength of electron‑lattice coupling in the film, as revealed by 2D magnetic maps constructed from photoemission electron microscopy (PEEM) images with x-ray magnetic circular dichroism (XMCD) contrast. For La0.67Sr0.33MnO3 films with relatively weak electron‑lattice coupling, strain due to electrically driven structural changes in the substrate modifies the local magnetization, yielding large and persistent magnetoelectric effects. For films of La0.7Ca0.3MnO3, stronger electron‑lattice coupling yields coexisting ferromagnetic and paramagnetic phases that may be interconverted by thermally driving phase transitions in the substrate. Magnetic cycling reveals that this interconversion may be driven via strain-mediated feedback to yield reversible changes in film entropy that are as large as the best magnetocaloric materials4. [1] W. Eerenstein, M. Wiora, J. L. Prieto, J. F. Scott and N. D. Mathur, _Nat. Mater._ **6** , 348 (2007). [2] C. Thiele, K. Dörr, O. Bilani, J. Rödel and L. Schultz, _Phys. Rev. B_ **75** , 054408 (2007). [3] X. Moya, L. E. Hueso, F. Maccherozzi, A. I. Tovstolytkin, D. I. Podyalovskii, C. Ducati, L. C. Phillips, M. Ghidini, O. Hovorka, A. Berger, M. E. Vickers, E. Defay, S. S. Dhesi and N. D. Mathur, _Nat. Mater._ **12** , 52 (2013). [4] K. A. Gschneidner Jr, V. K. Pecharsky and A. O. Tsokol, _Rep. Prog. Phys._ **68** , **** 1479 (2005).