Magnetoresistance of LSMO/(Cu2O, Ag) composites

Abstract

Electrical, structural and magnetoresistive properties of ceramic composites with different mass ratios of components were synthesized and studied: (Cu2O+CuO)x/(La0,7Sr0,3MnO3)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 Agy/(La0,7Sr0,3MnO3)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 La0,7Sr0,3MnO3. 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 La0,7Sr0,3MnO3 manganite with annealing at 1000-1050°C. It was shown that the synthesized composites with a mass ratio of components (Cu2O+CuO)0,43/(La0,7Sr0,3MnO3)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 Ag0,08/(LSMO)0,92 composition, the magnetoresistance values reach 5,5%.

Keywords

• ceramic composites
• magnetoresistance
• lanthanum-strontium manganite
• copper oxides
• silver nanoparticles
• percolation