A study of the magnetic and electrical crossover region of La((0.5 pm delta))Ca((0.5 mp delta))MnO3

摘要: The ground states of La1-xCaxMnO3 change from double-exchange-associated conducting ferromagnets at x 0.50 even when is varied only slightly around 0.50. We have performed a careful study the electrical and magnetic properties these materials for range samples with varying calcium doping x0.50. natures state transition were found to be sensitive not but also actual Mn4+ content materials. low-temperature resistivity x0.50 below charge-ordering temperature was drop decreasing in presence fields few teslas or slight Ca underdoping (x0.50), revealing some free carriers charge-ordered states. data therefore demonstrate coexistence ferromagnetic antiferromagnetic phases perovskite manganites. observe field-induced `annealing' due partial delocalization carriers.