title: Perpendicular magnetic tunnel junction with a strained Mn-based nanolayer.
abstract: A magnetic tunnel junction with a perpendicular magnetic easy-axis (p-MTJ) is a key device for spintronic non-volatile magnetoresistive random access memory (MRAM). Co-Fe-B alloy-based p-MTJs are being developed, although they have a large magnetisation and medium perpendicular magnetic anisotropy (PMA), which make it difficult to apply them to a future dense MRAM. Here, we demonstrate a p-MTJ with an epitaxially strained MnGa nanolayer grown on a unique CoGa buffer material, which exhibits a large PMA of more than 5 Merg/cm(3) and magnetisation below 500 emu/cm(3); these properties are sufficient for application to advanced MRAM. Although the experimental tunnel magnetoresistance (TMR) ratio is still low, first principles calculations confirm that the strain-induced crystal lattice distortion modifies the band dispersion along the tetragonal c-axis into the fully spin-polarised state; thus, a huge TMR effect can be generated in this p-MTJ.
authors.affiliation: WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: K Z
authors.initials: KZ
authors.lastname: Suzuki
authors.affiliation: WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Ranjbar
authors.affiliation: Research Center for Spectrochemistry, University of Tokyo, Tokyo 113-0033, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Okabayashi
authors.affiliation: Electrical Engineering and Electronics, Kyoto Institute of Technology, Kyoto 606-8585, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Miura
authors.affiliation: WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Sugihara
authors.affiliation: Department of Applied Physics, Tohoku University, Sendai 980-8579, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Tsuchiura
authors.affiliation: WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Mizukami