Irradiation-controlled giant magnetoresistance of PtMn-based spin valve

Abstract

He + -ion irradiation resulted in the direct ordering of PtMn without postannealing. Samples were irradiated with 2MeV He+ ions and a beam current of 1.08μA∕cm2 such that the corresponding surface temperature was 190°C. The exchange bias direction was set in situ during irradiation in a field of 900Oe. A high giant magnetoresistance (GMR) ratio of 11% was obtained in PtMn-based spin valves after He+ irradiation. The GMR is completely eliminated after it is irradiated with oxygen ions at 42keV. Combining He+ with oxygen-ion irradiation can provide magnetic patterning for GMR sensors.

Magnetic patterning by means of ion irradiation and implantation

“…The ion beam induced modification of the exchange coupling across an antiferromagnetic/ferromagnetic interface is widely investigated for exchange bias systems for spin-valves [47][48][49][50][51] and for magnetic tunnel junctions [52,53]. In all these cases the magnitude of the exchange bias effect is directly related to the exchange coupling across the mutual interface between the ferromagnet and the antiferromagnet.…”