Biphasic composite materials were synthesized near the La0.7Sr0.3MnO3-based percolation threshold and the second phase, which is an inorganic or organic compound — polyvinyl acetate, paraffin, carboxymethylcellulose, sucrose, and ultrafine silver particles. For composites with an organic matrix, the magnetoresistance values ​​do not exceed 2%, and for composites with silver particles - 8%. The values ​​of isotropic negative magnetoresistance for ceramic samples of 80% LSMO / 20% GeO2 (mass%) reach 13% in a 15 kOu magnetic field with a sensitivity of about 1% / ke in the low-field region. High chemical and radiation stability of these glass composites should be noted. The magnetoresistive properties of such compounds slightly decreased after 60 days of being in water with a salinity of 35 ppm. Composites of 80% LSMO / 20% GeO2 were exposed to X-rays with a dose of 7 Sv from the Co57 source. The magnetoresistive properties and electrical resistance of these composites did not change after that.

Keywords: lanthanum strontium manganite, ceramic two-phase material, one-step synthesis, radiation exposure, magnetoresistance, percolation threshold, dielectric constant, barrier layer, spin-dependent tunneling, spin polarization

The electrical properties of composites based on La0.7Sr0.3MnO3 (LSMO) synthesized at the percolation threshold have been studied: LSMO / Li4P2O7, LSMO / Sb2O3, LSMO / GeO2. The activation energies of these compounds have been determined. New ceramic materials with silver interlayers between LSMO manganite crystallites have been synthesized. The current-voltage characteristics for the LSMO / GeO2 series are given. The nonlinearity of the characteristics is most pronounced for compositions near the percolation threshold, 85% LSMO / 15GeO2.

Keywords: lanthanum strontium manganite, composite material, ceramics, one-step synthesis, magnetoresistance, percolation threshold, dielectric constant, barrier layer, tunneling, spin polarization