Magnetoresistance induced by low-field control of phase separation in La0.5Ca0.5MnO3 - art. no. 144419

The effect of low magnetic fields on the transport properties of a manganit e compound with magnetic phase separation is studied. The different behavio r obtained in samples of La0.5SCa0.5MnO3 related to the way in which the lo w field is applied is consistent with a picture of changes in the metallic fraction induced by the magnetic field in a field-cooled cycle. Using a sim ple model of conduction through a binary mixture, the interrelation between magnetoresistance, metallic fraction, and percolation temperature is accou nted for. A different physical coefficient relating magnetic field and meta llic fraction emerges as the relevant parameter in the description of phase separated manganites.