Magnetic properties of La2-xSrxCuO4 nanoparticles in mesoporous silica

Abstract

We synthesized the La2-xSrxCuO4 (x = 0 and 0.15) nanoparticles with particle size of about 12-13 nm in the pores of mesoporous silica and investigated their size effects through magnetic and ESR measurements. Magnetization curves for the nanoparticle with x = 0 exhibited rapid increase under low magnetic field as in ferromagnetic materials, and the magnetization increased linearly without saturation tendency. In contrast, magnetization for x = 0.15 consistently increased in proportion to magnetic field without diamagnetic behavior. ESR absorption spectra for both x = 0 and 0.15 were reproduced by summation of two absorption lines. Both the magnetic and the ESR measurement results suggested the coexistence of two magnetic components in each nanoparticle.