Applied Physics Letters · 2000 · 116 citations · 15 references
Natural SciencesMaterials EngineeringMaterials ScienceElectronic MaterialsMagnetic MaterialsNanomaterialsElectrode MaterialsFerromagnetic MaterialsFerromagnetismMagnetic OxidesSpintronic MaterialsSpintronicsBreakdown VoltageMagnetic Materials CharacterizationMagnetic Tunnel JunctionsMagnetic Tunneling JunctionsMagnetoresistanceSpin PolarizationTunnel JunctionsTunnel Magnetoresistance
Temperature dependence of tunnel magnetoresistance (TMR) ratio, resistance, and coercivity from 4.2 K to room temperature and applied voltage dependence of the TMR ratio and resistance at room temperature for a tunnel junction, Ta (5 nm)/Ni79Fe21 (3 nm)/Cu (20 nm)/Ni79Fe21 (3 nm)/Ir22Mn78 (10 nm)/Co75Fe25 (4 nm)/Al (0.8 nm)-oxide/Co75Fe25 (4 nm)/Ni79Fe21 (20 nm)/Ta(5 nm), were investigated. TMR ratio, effective barrier height and width, and breakdown voltage of the junction can be remarkably enhanced after annealing at 300 °C for an hour. High TMR ratio of 49.7% at room temperature and 69.1% at 4.2 K were observed. The value of spin polarization of Co75Fe25, P=50.7%, deduced from the TMR ratio at 4.2 K was corresponding well to the experimental data measured at 0.2 K in a spin polarized tunneling experiment using a superconductor/insulator/ferromagnet tunneling junction.
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