Observation of a tunneling magnetoresistance effect in magnetic tunneling junctions with a high resistance ferromagnetic oxide Fe2⋠5Mn0⋠5O4 electrode

►Fe2.5Mn0.5O4 as a novel spin injector on molecular spintronics was studied. ► The Fe2.5Mn0.5O4/Al−O/Ni80Fe20 junctions showed TMR effect at room temperature. ► The maximum TMR ratio in the junctions is 0.85% at RT. ► Spin-polarization of Fe2.5Mn0.5O4 is estimated to be at least 0.94% at RT.