  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 wavevector 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.
