Magnetoresistance of LSMO/(Cu₂O, Ag) composites

Electrical, structural and magnetoresistive properties of ceramic composites with different mass ratios of components were synthesized and studied: ( Cu ₂ O + CuO ) _x /( La _0,7 Sr _0,3 MnO ₃)_{1- x} ( x = 0,17; 0,22; 0,33; 0,43; 0,48; 0,53; 0,58; 0,63; 0,68; 0,72; 0,77; 0,82; 0,86; 0,91; 0,99), and Ag_y /( La _0,7 Sr _0,3 MnO ₃)_{1- y} ( y = 0; 0,02; 0,06; 0,08; 0,10; 0,12; 0,25; 0,50). The composites with copper oxides were synthesized using an original technology for sample preparation using dispersed copper and a pre-prepared ferromagnetic oxide with the perovskite structure La _{0,7 Sr 0,3 MnO 3}. Pressed mixtures with a copper content of less than 45% by weight were annealed at a temperature of 1050°C. At higher copper contents, annealing was performed at 1000°C. The compositions with silver nanoparticles were prepared by reduction from silver nitrate. The composites were synthesized using an original technology for sample preparation using dispersed copper and La _{0,7 Sr 0,3 MnO 3} manganite with annealing at 1000-1050°C. It was shown that the synthesized composites with a mass ratio of components ( Cu ₂ O + CuO )_0,43/( La _0,7 Sr _0,3 MnO ₃)_0,57 exhibit the highest magnetoresistance values of about 7% in a constant magnetic field of 14 kOe at room temperature. The maximum magnetoresistance correlates with a special region of change in the dependence of electrical resistance on the component ratio in these compositions. In the Ag _0,08/( LSMO )_0,92 composition, the magnetoresistance values reach 5,5%.

ceramic composites, magnetoresistance, Lanthanum-strontium manganite, copper oxides, silver nanoparticles, percolation