Magnetic properties of nano-clusters lanthanum chromite powders doped with samarium and strontium ions synthesized via a novel combustion method

A novel approach to synthesize a single-phase orthorhombic perovskite lanthanum chromite LaCrO3 clusters doped with Sm3+ and Sr2+ ions via gel combustion route was reported. The producing materials were synthesized using metal nitrates as oxidizers and triethanol amine (TEA), N-butyl amine (NBA) or ethylene diamine (EDA) as a fuel. The effect of the annealing temperature, type of organic fuel and the variation of the samarium and/or strontium substitution and its impact on crystal structure, crystallite size, microstructure and magnetic properties of the LaCrO3 powders formed was systematically studied. The results revealed that a well crystalline single phase of pure LaCrO3 can be achieved at annealing temperature from 800 to 1000 °C for 2 h. Moreover, each organic carrier materials exhibited a different degree of effectiveness in the synthesis of the mixed oxide powders. The crystal structure was influenced by doped Sm3+ and/or Sr2+ ions. The crystallite size of the produced powders was increased with the increase the annealing temperature, increasing the Sm3+ ion and the decrease of Sr2+ ion substitution. The microstructures of the produced powders were found to be nanoclusters octahedra-like shaped. The saturation magnetization of the LaCrO3 powders increased continuously with an increase in the Sm3+ ion concentration and it decreased with an increase in the Sr2+ ion up to 0.3 at annealing temperature of 1000 °C for 2 h. The maximum saturation magnetization (0.279 emu/g) was achieved at the Sm3+ ion molar ratio 0.3 and annealing temperature 1000 °C. Moreover, wide coercivities can be obtained at different synthesis conditions (49.25 to 522  Oe).