The physics of the colossal magnetoresistance CMR manganite systems has received
significant scrutiny in recent years, 1–13 in part because in these materials the spin, charge,
orbital, and lattice systems are intimately coupled. One important experimental finding is that
many physical properties, most notably the magnetic transition temperature, the magnetic
moment observed in the low temperature magnetic phase, and the magnitude and
temperature dependence of the electrical conductivity display unusually high degree of …