TEMPERATURE-DEPENDENCE OF ITINERANT-ELECTRON JUNCTION MAGNETORESISTANCE

In itinerant electron ferromagnets, spectral weight is transferred at finite temperatures from quasiparticle peaks located at majority- and minority-spin band energies to shadow-band peaks. For a given Bloch wa ve vector and band index, the majority-spin shadow-band peak is locate d near the minority-spin quasiparticle energy and the minority-spin sh adow-band peak is located near the majority-spin quasiparticle energy. This property can explain much of the temperature dependence seen in the magnetoresistance of magnetic tunnel junctions.