Skip to main content

Engineering the electronic properties of manganite heterostructures and interfaces for oxitronic applications

Posted in

PhD subject :

Oxide electronics (or “oxitronics”) materials provide a plethora of possible applications and offer many opportunities for scientists to probe some of the most exciting and intriguing phenomena exhibited by oxide systems and oxide interfaces. Among these oxides, the ABO3 perovskite structure yields a fascinating class of materials, where almost all kinds of physical properties can be found (metallic, insulating, superconductivity, magnetism, ferroelectricity, etc…). For instance, BiFeO3 is exhibiting simultaneously ferroelectricity and antiferromagnetism, resulting in a rather unique room temperature multiferroic. The manganites, AMnO3, such as (La,Sr)MnO3 or CaMnO3, have also a very complex phase diagram encompassing ferromagnetism and metal-insulator transition. Furthermore, new properties are observed for heterostructures based on thin films of manganites, notably due to the presence of interfaces (with 3d perovskite such as BiFeO3, but also with 4d or 5d perovskites).
For instance, a giant modulation of the resistivity upon a control of the ferroelectric polarization has been reported for tunnel junctions based on a metal/BiFeO3/CaMnO3 structures. More recently, interfaces based on (La,Sr)MnO3 have been proposed as a possible spin to charge current converter. The BiFeO3/(La,Sr)MnO3 interface might also enable manipulation of spin waves that is an essential development for future magnon-based technologies. For all these applications, the role of the structure and electronic structure reconstruction at interfaces is crucial and remains unknown on many aspects. Indeed, both structural and electronic structures can be very different from the bulk near the interface and often change at subnanometer scale (due to potential discontinuity at interface, to strain and strain relaxation at several nanometers of the interface, etc..).
The PhD student will have to investigate the structure and electronic structure of heterostructures and interfaces based on manganite thin films, by using a combination of X-ray (Soleil synchrotron) and electron (LPS-university Paris-Sud) based spectroscopic and microscopic techniques. Both techniques, when done at the state-of-the-art, can have spatial or in-depth resolution enabling the studies of interface heterogeneities.
The student will strongly interact with the Unité Mixte de Physique CNRS-Thales laboratory (Palaiseau) where samples will be grown and physical properties measured. The goal is to elucidate the role of interfacial mechanisms for a further engineering of the functionality through a tailoring of the electronic properties. The PhD thesis is part of the AXION program funded by the LabEx NanoSaclay.

Contacts :
J.P. Rueff (jean-pascal.rueff@synchrotron-soleil.fr)
A. Gloter (alexandre.gloter@u-psud.fr)

starting :
fall 2019 (3 years)

more details are enclosed in the .pdf files.

PreviewAttachmentSize
these-AXION-advanced-carac-vg.pdf702.3 KB