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MA: Fachverband Magnetismus

MA 26: Thin Films: Magnetic Coupling Phenomena / Exchange Bias

MA 26.5: Vortrag

Dienstag, 21. März 2017, 15:00–15:15, HSZ 101

Tunneling magnetoresistance on perpendicular CoFeB-based junctions with perpendicular exchange bias — •Orestis Manos, Alexander Boehnke, Robin Klett, Panagiota Bougiatioti, Karsten Rott, Alessia Niesen, Jan Schmalhorst, and Günter Reiss — Center for Spinelectronic Materials and Devices, Department of Physics, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany

Recently, magnetic tunnel junctions with perpendicular magnetized electrodes (pMTJs) combining perpendicular exchange bias (PEB) films have attracted considerable scientific interest. In this project, we fabricated and investigated the magneto-transport properties of the pMTJs stacks: Ta/Pd/IrMn/CoFe/Ta/Co-Fe-B/MgO/Co-Fe-B/A/Pd where A=Hf, Ta displaying PEB fields of 500 Oe [1] along with high PMA. From the magnetic loops is observed the noticeably higher PMA of the free layer for the Hf capped compared to the Ta capped CoFeB layer. Additionally, from the major tunnel magnetoresistance (TMR) loops at room temperature, we extract a value of equal to 50% and 40% in Hf and Ta capped stacks, respectively. The enhancement of PMA and TMR of Hf capped stack is attributed to the greater Boron absorbance of Hf compared to Ta [2-3]. Furthermore, for both samples is extracted the significantly enhanced TMR at low temperatures, reaching 105% at 10K for the sample with Hf as a capping layer.
[1] X. Zhang et al., IEEE Trans. Magn., 51, 11 (2015)
[2] A. Hindmarch et al., Appl. Phys. Express, 4, 013002 (2011)
[3] J. D. Burton et al., Appl. Phys. Lett., 89, 142507 (2006)