Low-Temperature Resistivity in a Nearly Half-Metallic Ferromagnet

In a nearly half-metallic ferromagnet, such as a material exhibiting ``colossal'' magnetoresistance, the minority spin electrons close to the band edge at the Fermi energy are Anderson localized due to disorder; thus only majority electrons conduct current. This presents a unique electronic structure for which the linear response Boltzmann equation involving the scattering of a single magnon is exactly solvable. The solution yields a temperature dependent resistivity that scales as T2.5 above approximately 60 K and contains a T1.5 contribution below this temperature, and has a dependence on the magnetic field consistent with experiments.