Room-Temperature Tunneling Magnetoresistance in Magnetic Tunnel Junctions with a D0₃-Fe₃Si Electrode

Abstract

To inform room-temperature spin functionality of D03-ordered Fe3Si, we explore tunneling magnetoresistance (TMR) effects in magnetic tunnel junctions (MTJs) consisting of Co60Fe40/AlO x /Fe3Si on Si. We clearly observe reproducible TMR ratios of ∼20% at room temperature for all MTJs fabricated. By using Julliere's formula, the room-temperature spin polarization (P) value for D03-ordered Fe3Si can be roughly estimated to be ranging from 0.18 to 0.45 when we assume the P values from 0.5 to 0.2 for Co60Fe40. This study reveals that the room temperature P value for D03-ordered Fe3Si is relatively small compared with that for Co-based Heusler alloys reported previously.

Temperature-dependent magnetoresistance effects in Fe3Si/FeSi2/Fe3Si trilayered spin valve junctions

“…Recently, Fe3Si has been employed as a spin injection electrode in Co60Fe40/AlOx/Fe3Si tunnel junctions [13] and in spin injection to Si [14]. We have studied spintronics based on a Fe-Si system comprising ferromagnetic Fe3Si and semiconducting FeSi2 thus far [15,16,17,18,19,20,21,22,23,24,25,26].…”

A magnetic tunnel junction with an L21-ordered Co2FeSi electrode formed by all room-temperature fabrication processes

“…Here, the shape of the MR curve in low field region depends on the magnetization rotation due to a misalignment between magnetic easy axis of the epitaxial Co 2 FeSi layer and the external-field direction, as discussed in our previous study. [21] We note that such TMR ratios (solid curves) are usually larger than those (dashed curves) for our previous MTJs with heat treatments. [21] This feature in-dicates that, the room-temperature grown Co 2 FeSi layer has relatively high P compared to the 130 • C-grown D0 3 -Fe 3 Si.…”

“…From the TMR ratios, the room-temperature P for Co 2 FeSi is estimated to be ranging from 0.25 to 0.61. Despite room-temperature fabricated Co 2 FeSi, its P is larger than that for D0 3 -Fe 3 Si grown at 130 • C. [21]…”

Magnetoresistance effects in current‐perpendicular‐to‐plane structures based on Fe3Si/FeSi2 artificial lattices

“…Thus far, Fe/Si [16][17][18], Fe/Fe-Si [19,20], and Fe/Fe 1-x Si x [21] artificial lattices have been studied. Actually, researches of spintronics that employ Fe 3 Si for spin injection source have been actively made [22][23][24][25][26][27][28].…”