Perovskite manganite magnetic tunnel junctions with enhanced coercivity contrast

We have fabricated (La,Sr)MnO3 (LSMO)-based magnetic tunnel junctions with Ru-doped LSMO (LSMRO) film used as one of the electrodes. The Ru doping enhances the coercivity of LSMO, resulting in a sharp steplike tunnel magnetoresistance (TMR) response with a high contrast in the coercive field (H-c) for magnetization reversal. Although the difference of the H-c between the top LSMRO and the bottom LSMO electrodes decreases with increasing the temperature, it is large enough to give a clear TMR response even at a relatively higher temperature region of around 200 K. By changing the dimensions of the top LSMRO electrode, the H-c is found to have no dependence on the geometric aspect variations of the top electrode but slightly on the junction area. (c) 2005 American Institute of Physics.