Perpendicular compensated ferrimagnetic tunnel junctions

Combining the advantages of ferromagnetic and antiferromagnetic tunnel junctions, ferrimagnetic tunnel junctions are highly desirable for spintronic applications. Here, we design and experimentally demonstrate a novel type of perpendicular compensated ferrimagnetic tunnel junction composed of the ferrimagnetic oxide NiCo2O4 and the compensated ferrimagnetic alloy Co100-x Gdx separated by an MgAl2O4 insulating barrier. The tunneling magnetoresistance undergoes a sign transition from positive to negative (from +72% to -22%) as the temperature increases across the magnetization compensation point of Co100-x Gdx , which is attributed to the reversible magnetic dominance between the Co and Gd sublattices. Furthermore, we employ this ferrimagnetic tunnel junction to realize temperature-dependent non-volatile multilevel states. Our findings on the perpendicular compensated ferrimagnetic tunnel junctions can provide an attractive avenue for developing ferrimagnet-based devices.