A5: Growth, structure and magnetic properties of ultra thin transition metal oxides on metals
The project focuses on the analysis of the geometric structure and the magnetic properties of functional oxide films and interfaces. Due to their possible applications in modern information technology [e.g. tunnelling magneto resistance (TMR) devices and exchange bias systems], heterostructures composed of 3d-transitionmetal oxides and metals have attracted considerable attention.
Multi-ferroic systems represent a new class of materials in the context of developing devices for recording aaplications and sensor materials, in which the interaction between the ferroelectric and the ferromagnetic component is mediated by piezoelectric/magnetostrictive coupling. Multilayers of CoFe2O4 and BaTiO3 represent one prototype for this class of systems. In addition, different coupling mechanisms are under investigation, which are based on the modification of the interface electronic structure. Currently the Fe/BaTiO3 heterostructure represent one prototype example for this class of materials.
Since the geometric structure of oxide films is decisive for their physical properties, a precise structure analysis is mandatory for film preparation and understanding their physical properties. Here, atomic resolution and chemical sensitivity even in complex systems are required. In this context x-ray diffraction is well suited for this purpose. Therefore our project is of central importance within the SFB. It is also in close relation to projects dealing with theoretical aspects (A4, B2, B7) of electronic transport and of the electronic and magnetic properties. They rely on precise structure data. Further relations exist to projects, in which experiments are carried out providing complementary information (e.g. electron microscopy, electron scattering, x-ray absorption spectroscopy, scanning tunnelling microscopy and analysis of surface stress in projects A1, A3, A7 and B8).
The project will focus on NiO and CoO deposited on metal surfaces such as Ag(001) and Fe(001). With regard to the class of doped oxides (ZnO, ZrO2), which are planned to play a major role in the project, we plan to investigate growth, structure and magnetic properties after deposition on different substrates (non-magnetic and magnetic). In this context multilayers consisting of differently doped oxides [e.g. Zn(Co)O/ZnO/Zn(Co)O] are also of importance, since they might represent new architectures for TMR systems. Concerning the class of multiferroics we want to study the heterostructures CoFe2O4/BaTiO3 and Fe/BaTiO3.
Film preparation both, reactive deposition of thermally evaporated metals and pulsed laser deposition (PLD) will be used. Because of the importance of the PLD technique for sample preparation, the MPI plans to provide funding for a new excimer laser (KrF, wavelength=248 nm) provided that the SFB will be established.
Principal Investigators
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PD Dr. Holger Meyerheim ⇒
phone: +49 (0) 345/55 82633 fax: +49 (0) 345/55 11223 |
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Prof. Dr. Jürgen Kirschner ⇒
phone: +49 (0) 345/55 82655 fax: +49 (0) 345/55 11223 |
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