Interfacial structure/chemistry of spintronics devices with Heusler alloy electrodes

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Discovering the structure/chemistry property relationship of interfaces in spintronic devices comprising half metal Heusler alloys as electrodes. Beside the interface between Heusler alloys and oxide barriers used in tunneling magnetoresistance (TMR) devices, special attention will be paid to Heusler alloys in contact to metallic spacer materials and semi-conductors in order to open up new applications in current-perpendicularrto-plane giant magnetoresistance (CPP-GMR) and spin-injectors. Functional TMR and GMR layer structures are produced by sputter deposition and molecular beam epitaxy. Selected materials of barriers and spacer layers and the composition of the Heusler alloys will be varied to determine the effect on interfacial structure, order and local chemistry of the respective interfaces. To clarify the effect of interface segregation, the local composition of interfaces will be directly modified by controlled dusting in molecular beam epitaxy. These prepared structures will be electrically and magnetically characterized after suitable heat treatment. To detect smallest variations of interfacial composition, state-of-the-art laser-assisted atom probe tomography will be applied. High resolution and analytical TEM will be used to characterize ordering state and morphology of the intermetallic Heusler alloys.