A self-consistent calculation and an anisotropic wavelength cutoff energy of spin-wave spectrum in magnetic tunnel junctions

Temperature dependence of tunnel magnetoresistance (TMR) ratio, resistance, and coercivity from 4.2 K to room temperature (RT), applied de bias voltag e dependence of the TMR ratio and resistances at 4.2 K and RT, tunnel curre nt I and dynamic conductance dI/dV as functions of the de bias voltage at 4 .2 K, and inelastic electron tunneling (IET) spectroscopy, d(2)I/dV(2) vers us V, at 4.2 K for a tunnel junction of Ta(5 nm)/Ni79Fe21(25 nm)/Ir22Mn78(1 2 nm)/Co75Fe25(4 nm)/Al(0.8 nm)-oxide/Co75Fe25(4 nm)/Ni79Fe21(25 nm)/Ta(5 n m) were systematically investigated. High TMR ratio of 59.2% at 4.2 K and 4 1.3% at RT were observed for this junction after annealing at 275 degreesC for an hour. The temperature dependence of TMR ratio and resistances from 4 .2 to 300 K at 1.0 mV bias and the de bias voltage dependence of TMR ratio at 4.2 K from 0 to 80 mV can be evaluated by a comparison of self-consisten t calculations with the experimental data based on the magnon-assisted inel astic excitation model and theory. An anisotropic wavelength cutoff energy of spin-wave spectrum in magnetic tunnel junctions (MTJs) was suggested, wh ich is necessary for self-consistent calculations, based on a series of IET spectra observed in the MTJs.