Current induced magnetization switching in magnetic tunnel junction with MgO [001] tunnel barrier

Magnetic tunnel junction (MTJ) consisting of Ta/CuN/Ta/Pt₅₀Mn₅₀/Co₇₀Fe₃₀/Ru/Co₆₀Fe₂₀B₂₀/MgO/Co_{60Fe20B20/Ta/Ru is prepared on a thermally oxidized silicon wafer by sputtering. Magnetoresistance is measured using AC four-point-probe method with applying magnetic field along the long axis of the elements. Current induced magnetization switching (CIMS) is measured by applying short current pulses. Results show that the MTJs showed large magnetoresistance of about 130% at room temperature and at a low bias voltage. A minor loop corresponding to the magnetization reversal of the free layer shows sharp switchings of the resistance. The resistance change due to CIMS is about 164 Ω (ΔR), which corresponds to 76% of the resistance change due to magnetic field sweep. A possible reason for this is the degradation of insulating property of the thin MgO barrier during the repetition of current bias sweep.}