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 wave vector and band index, the majority-spin shadow-band peak is located near the minority-spin quasiparticle energy and the minority-spin shadow-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.

• Received 18 December 1997

DOI:https://doi.org/10.1103/PhysRevLett.81.705