Magnetic and transport properties of the charge-ordered manganite Pr2/3Ca1/3MnO3

The transport properties, ac susceptibility χ, and EPR spectra have been studied for the insulator polycrystalline manganite Pr2/3Ca1/3MnO3 undergoing the orbital (O) and charge (C) orderings below T CO ∼ 250 K that lead to antiferromagnetic (AF) ordering below T N ≈ 155 K. Above T C ∼ 110 K, the χ′(T) dependence indicates that the sample contains a phase undergoing a second-order transition from the paramagnetic to ferromagnetic state. In the vicinity of T C , the colossal magnetoresistance effect is observed. The EPR spectrum characteristics are sensitive to the development of the O/C and AF orderings, and they show peculiarities at T CO and T N . Between T CO and T N , the temperature dependence of the g factor exhibits a characteristic point that can be related to the appearance of the electric polarization revealed in manganites of this class.