Dresden 2017 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 17: Magnetic Heuslers, Half-Metals and Oxides (joint session MA, TT, organized by MA)

TT 17.6: Talk

Monday, March 20, 2017, 16:15–16:30, HSZ 403

Tunneling Magnetoresistance in MnRuGa based Magnetic Tunnel Junctions — •Aleksandra Titova^1,2, Ciaran Fowley¹, Kiril Borisov³, Davide Betto³, Yong Chang Lau³, Nivetha Thiyagarajah³, Gwenael Atcheson³, Michael Coey³, Plamen Stamenov³, Karsten Rode³, Jürgen Lindner¹, Jürgen Faßbender^1,2, 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.