QWELLMAGNA

The objective of the QWellMagNa project is to study magnetic nanostructures embedded in metallic matrixes. The originality of the project is twofold: on one hand it is based on the use of spectroscopic properties of quantum wells (QW) formed between the magnetic particles and the surface, on the other hand it relies on an ambitious experimental approach using scanning tunnel microscopy with functionalized active microfabricated tips. The nanoparticles buried a few nanometers below the surface confine the electrons between their magnetic interface and the surface of the matrix forming quasi-open QW. QW will be detected by scanning tunneling microscopy / spectroscopy (STM / STS) with active planar magnetic probes. The spectroscopic properties of QW reflects the position and the depth of the nanoparticles but also their shape and their magnetic state. The detailed analysis of the spatial variation at the surface of the electron density will therefore make possible to extract this information. The original use of "tip-on-chip" active planar probes allows us to locally generate the magnetic fields necessary both for the magnetic detection (modulation) and for the magnetic manipulation of nanoparticles. This field will be generated by current pulses flowing across an special structure on the STM tip specifically designed for this purpose. The probes developed within the framework of this project will be manufactured by standard lithography processes and could be adaptable to any tunnel microscopy equipment, thus broadening the area of application of the STM. We will also work on the individual manipulation of the magnetic state of an individual nanoparticle in an assembly which offers unique perspectives for studying the effects of magnetization dynamics of correlated systems with QW states.