Effect of insertion layer on electrode properties in magnetic tunnel junctions with a zero-moment half-metal

Aleksandra Titova, Ciarán Fowley, Eugene Clifford, Yong Chang Lau, Kiril Borisov, Davide Betto, Gwenael Atcheson, René Hübner, Chi Xu, Plamen Stamenov, Michael Coey, Karsten Rode, Jürgen Lindner, Jürgen Fassbender, Alina Maria Deac

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Due to its negligible spontaneous magnetization, high spin polarization and giant perpendicular magnetic anisotropy, Mn 2 Ru x Ga (MRG) is an ideal candidate as an oscillating layer in THz spin-transfer-torque nano-oscillators. Here, the effect of ultrathin Al and Ta diffusion barriers between MRG and MgO in perpendicular magnetic tunnel junctions is investigated and compared to devices with a bare MRG/MgO interface. Both the compensation temperature, T comp , of the electrode and the tunneling magnetoresistance (TMR) of the device are highly sensitive to the choice and thickness of the insertion layer used. High-resolution transmission electron microscopy, as well as analysis of the TMR, its bias dependence, and the resistance-area product allow us to compare the devices from a structural and electrical point of view. Al insertion leads to the formation of thicker effective barriers and gives the highest TMR, at the cost of a reduced T comp . Ta is the superior diffusion barrier which retains T comp , however, it also leads to a much lower TMR on account of the short spin diffusion length which reduces the tunneling spin polarization. The study shows that fine engineering of the Mn 2 Ru x Ga/barrier interface to improve the TMR amplitude is feasible.

Original languageEnglish
Article number4020
JournalScientific reports
Volume9
Issue number1
DOIs
Publication statusPublished - 2019 Dec 1
Externally publishedYes

ASJC Scopus subject areas

  • General

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