Perpendicular anisotropy magnetic tunnel junctions and thermally assisted writing.

Summary In the context of increasing the storage density of magnetoresistive random access memories (MRAMs), materials with perpendicular magnetic anisotropy are particularly interesting because they possess very high anisotropy. However, this increase in anisotropy also induces an increase in write power consumption. A new concept of thermally assisted writing has been proposed by the SPINTEC laboratory. The principle is to design a very stable structure at room temperature, but which loses its anisotropy when heated, thus facilitating writing. The aim of this thesis is to experimentally validate this concept. The first chapters are devoted to the optimization of materials with perpendicular anisotropy such as (Co/Pt), (Co/Pd) and (Co/Tb) multilayers. Their integration in a magnetic tunnel junction is then presented. The evolution of the anisotropy in temperature, a crucial parameter for the proper functioning of the thermal assistance, has also been studied. Finally, it is shown that the thermally assisted writing is particularly efficient: the developed structures present a reduced writing consumption compared to conventional structures and a high stability at room temperature.