We report results of integrated study of resistivity, magnetoresistance, Hall effect, thermopower, and magnetothermopower in La 1Ϫx Sr x MnO 3 single crystals with xϭ0. 15,0.20,0.25. The focus is on the vicinity of the Curie temperature. It is shown that near T C where the colossal magnetoresistance is observed the crystals are in insulator state. It is established that the conductivity in the manganites with different level of doping differs in nature. Near T C , temperature and magnetic-field dependences of resistivity arise due to change of activation energy, which is linear in squared magnetization. The metal-insulator transition in the xϭ0.20 and 0.25 manganites occurs not at a certain temperature but in a temperature interval about 80 K wide.
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