NEW EPITAXIAL MULTILAYER SYSTEM FOR SPIN-VALVE MAGNETIC SENSORS

Experimental results on a new ''spin-valve'' system for magnetoresistive detection, based on epitaxial Fe/Pd bilayers grown on MgO single crystals, are presented. These Fe/Pd bilayers display particularly sensitive magnetic properties, which are shown to result directly from the presence of the polarized Pd interface. A magnetically hard trilayer is subsequently grown onto the soft Fe/Pd bilayer, forming an epitaxial spin-valve system which displays abrupt transitions between states of parallel and antiparallel alignment of the two magnetic layers. The field sensitivity of the resistivity at low temperatures attains 0.3% per Oe in a Fe/Pd/Cu/Co/Cu system.