Regensburg 2016 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 17: Poster Session I
MA 17.68: Poster
Dienstag, 8. März 2016, 09:30–12:30, Poster B1
Perpendicular CoFeB-based magnetic tunnel junctions with exchange bias — •Orestis Manos, Jan Schmalhorst, and Günter Reiss — Center for Spinelectronic Materials and Devices, Physics Department, Bielefeld University, Germany
This study investigates CoFeB-based magnetic tunnel junctions with perpendicular magnitized electrodes (pMTJs) combing exchange bias (EB). The magnetically soft electode is on top of the sample, consting of SiO2/Mo(5)/MgO(1.8)/Co-Fe-B(1)/Mo(5) in (nm). The pinned bottom electrode is formed as SiO2/Ta(10)/Ru(30)/Ta(5)/A(20)/X(10)/Co-Fe-B(1.2)/MgO(1.8) in (nm) where A=Pt, Ru and X=FeMn, IrMn [1]. In the aforementioned samples, the EB effect is observed as a shift of the magnetic hysteresis loop away from zero field, accompanied by an increase in coercivity. The phenomenon is related to the exchange interface interactions between the ferromagnet (FM) and the antiferromagnet (AFM). The crystallographic growth of the AFM affects critically the strength of the EB. The first aim is to change the growth direction of the FeMn/IrMn (111) from in-plane to perpendicular to the sample plane. The EB films were ex-situ post-annealed at several temperatures and their crystallograpic properties were investigated by X-ray diffraction (XRD). A [111] growth direction obtained for all seed layers. The samples with FeMn and IrMn combining Pt as a seed layer showed a perpendicular exchange bias field of 100 and 250 Oe, respectively.
[1] F. Garcia et al., J. Appl. Phys. 91, 6905 (2002)