Dresden 2017 – scientific programme
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MA: Fachverband Magnetismus
MA 15: Magnetic Heuslers, Half-metals and Oxides (jointly with TT)
MA 15.6: Talk
Monday, March 20, 2017, 16:15–16:30, HSZ 403
Tunneling Magnetoresistance in MnRuGa based Magnetic Tunnel Junctions — •Aleksandra Titova1,2, Ciaran Fowley1, Kiril Borisov3, Davide Betto3, Yong Chang Lau3, Nivetha Thiyagarajah3, Gwenael Atcheson3, Michael Coey3, Plamen Stamenov3, Karsten Rode3, Jürgen Lindner1, Jürgen Faßbender1,2, and Alina Deac1 — 1Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany — 2Technische Universität Dresden, Germany — 3Trinity College, Dublin, Dublin, Ireland
Some intermetallic Heusler compounds display high spin polarization and low magnetic moment. Thin-film samples can possess huge uniaxial anisotropy fields, exceeding tens of teslas. This, combined with their tuneable properites, make these materials very attractive for THz based spin-transfer-torque oscillators. Recently new material from this family was discovered - MnRuGa (MRG) - the first experimentally achieved fully-compensated half-metallic ferrimagnet. Here we show that MRG can be integrated in perpendicular anisotropy magnetic tunnel junctions stacks. Tunneling magnetoresistance (TMR) ratios up to 40% are observed. We also demonstrate that the TMR exists even when the net magnetization of MRG is strictly zero, implying that, at compensation, MRG exhibits a sizable spin polarization. The role of different diffusion barrier layers between MRG and the tunneling barrier as well as annealing temperature was investigated.
This work is supported by the Helmholtz Young Investigator Initiative Grant No. VH-N6-1048.