Structure and Magnetism of LSMO/BTO/MgO/LSMO Multilayers

J. Pawlaka, A. Żywczakb, G. Szwachtac, J. Kanakd, M. Gajewskab and M. Przybylskia,b aFaculty of Physics and Applied Computer Science, AGH University of Science and Technology, Kraków, Poland bAcademic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Kraków, Poland cFaculty of Metals Engineering and Industrial Computer Science, AGH University of Science and Technology, Kraków, Poland dDepartment of Electronics, Faculty of Informatics, Electronics and Telecommunications, AGH University of Science and Technology, Kraków, Poland

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A multiferroic tunnel junction (MFTJ) is a promising device for future memory systems with discrete and different logic states which are controlled by a combination of electric and magnetic fields. The goal of ongoing research is to present ferroelectric and ferromagnetic properties, especially at room temperature (RT), represented as high values of tunnel electroresistance (TER) and tunnel magnetoresistance (TMR). A key aspect is the appropriate preparation of a sample allowing epitaxial growth. The thin layers were prepared by pulsed laser deposition on atomically smooth monocrystalline SrTiO3 (STO) substrates. The ferromagnetic metal layers La0.67Sr0.33MnO3 (LSMO) are separated by a layer of a ferroelectric insulator - BaTiO3 (BTO). The same structure of LSMO, BTO and STO (perovskite) and a similar lattice constant make it possible to obtain high-quality heterostructures. Magnetic measurements confirm differences in the magnetic coercivity of the top and bottom LSMO layer, which allows to obtain their parallel and antiparallel magnetization orientation. A modification of the interfaces of BTO by thin MgO layer enables an increase in the value of the TER effect.

DOI: 10.12693/APhysPolA.133.548 PACS numbers: 75.60.Ej