Magnetotransport properties of flux melt grown single crystals of Co-substituted manganites with perovskite structure

Single crystals of La1-xBaxMn1-yCoyO3 (0.26≤x≤0.37; 0≤y≤0.31) perovskites were grown by the flux melt technique using the BaO-B2O3-BaF2 ternary system as a solvent. It was found that the cobalt content in the crystals is determined by the average oxidized state of the manganese ions and depends nonlinearly on the molar ratio of Co/Mn in the initial mixture. All the crystals exhibit ferromagnetic behaviour at low temperatures as well as a jump of resistivity and a magnetoresistance peak around the Curie temperature, gradually decreasing as the cobalt content increases. The low-temperature ferromagnetic phase transforms from the metallic to the semiconducting state with increase in cobalt content