Kinetic effects in an La0.8Ba0.2MnO3 single crystal

Results are presented of a complex study of the magnetic and resistive prop erties, the Hall effect, the thermal emf, and the longitudinal Nernst-Ettin gshausen effect of an La0.8Ba0.2MnO3 single crystal at temperatures between 77 and 400 K. A maximum was observed near the Curie temperature T-c on the temperature dependences of the resistivity, the thermal emf, and the norma l Hall coefficient. It was established that the Hall mobility remains const ant near T-c . It is shown that these anomalies in the kinetic properties a re attributable to a change in the position of the mobility edge relative t o the Fermi level. A semiphenomenological theory is put forward to quantita tively describe the temperature and magnetic-field dependences of the resis tivity and thermal emf of lanthanum manganites near the phase-transition te mperature. (C) 2000 MAIK "Nauka / Interperiodica".