- https://www.cells.es/ca/actualitat/agenda/esdeveniments-publics-dalba/electronic-and-spin-reconstructions-at-multiferroic-interfaces
- Electronic and spin reconstructions at multiferroic interfaces
- 2019-06-13T12:00:00+02:00
- 2019-06-13T13:00:00+02:00
- By Prof. Jacobo Santamaria Univ. Complutense de Madrid
- Què
- events
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Jun 13, 2019
de 12:00 a 13:00 (Europe/Madrid / UTC200) - On
- ALBA Synchrotron, Maxwell Auditorium
- Nom de contacte
- Manuel Valvidares
- URL de l'esdeveniment
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The electronic reconstruction occurring at oxide interfaces may be the source of interesting device concepts for future oxide electronics. Among oxide devices, multiferroic tunnel junctions are being actively investigated as they offer the possibility to modulate the junction current by independently controlling the switching of the magnetization of the electrodes and of the ferroelectric polarization of the barrier. In this talk I will discuss the interplay between ferroelectric polarization and the ionization of oxygen vacancies, a ubiquitous defect in perovskite oxides. Oxygen vacancies generated in an electrochemically active ferroelectric barrier control the stability of the ferroelectric polarization and modify its coercive fields and the domain structure [1]. The ferroelectric polarization, in turn, controls the ionization of oxygen vacancies well above the limits of thermodynamic equilibrium, triggering the build-up of a Schottky barrier at the interface which can be turned on and off with ferroelectric switching [2]. The strong coupling found between electrochemical and electronic degrees of freedom sheds light on the growing debate between resistive and ferroelectric switching in multiferroic tunnel junctions, and moreover, can be the source of novel concepts in memory devices and neuromorphic computing. I will furthermore discuss that coupled oxygen vacancy and ferroelectric switching is the source of novel electronic and spin reconstructions at the interfaces which may give rise to the nucleation of exciting groundstates. In particular, I will show that the spin reconstruction at the interfaces of a La0.7Sr0.3MnO3 /BaTiO3 / La0.7Sr0.3MnO3 multiferroic tunnel junction is the origin of a spin filtering functionality which can be turned on and off by reversing the ferroelectric polarization [3]. The ferroelectrically controlled interface spin filter enables a giant electrical modulation of the tunneling magnetoresistance between values of 10% and 1000%, that could inspire device concepts in oxides based low dissipation spintronics.
References:[1] G. Sanchez-Santolino et al. Nature Nanotechnology 12, 655 (2017)
[2] D. Hernández-Martín et al Nature Comms (under consideration)
[3] J. Tornos et al., Phys. Rev. Lett. 122, 037601 (2019)
