Large infrared magnetotransmission effect in composite and nano-composite based on Nd0.5Sr0.5MnO3

Abstract

Large negative magnetotransmission effect Δt/t0 = (tH − t0)/t0 (where tH, t0 are the light transmissions with and without magnetic field, respectively) of up to 9% was revealed in composites contained coarse-grained and nano-powders of Nd0.5Sr0.5MnO3 in the infrared (IR) range near the Curie temperature in magnetic field H = 8 kOe. The optical density spectra and magnetotransmission effect of the composites are discussed in the context of the polar centers phase model. In the nano-powder composite, the significant magnetotransmission of ∼7% takes place in wide temperature region far below TC. This fact is explained by the existence of the localized charge carriers and spin disorder at the nano-particles surface. An applied magnetic field reduces spin disorder and the localization of charge carriers resulting in negative magnetotransmission effect. Two magnetic phase transitions and phase separation in Nd0.5Sr0.5MnO3 promote the large magnetotransmission effect in a wide temperature range. The Nd0.5Sr0.5MnO3 nano-powder composite is a promising material for magnetooptical devices with a wide working temperature range.

X-ray Diffraction and X-ray Spectroscopy Studies of Cobalt-Doped Anatase TiO2:Co Nanopowders

“…One can suggest that the diffusion of cobalt is followed by the tendency of nanoparticles to form agglomerates. Such agglomerates formed by nanoparticles exist, for example, in nanostructured powders of manganites , and TiO 2 nanoparticles . In this way, soft X-ray spectroscopy allows to probe a surface part of the agglomerates which is rich of cobalt ions in the 2+ oxidation state.…”

X-ray spectra and charge states of cations in nanostructured manganites La0.5Ca0.5MnO3 and Nd0.5Sr0.5MnO3

“…A maximum in the size distribution particles for the powder after the grinding for 8 h was ∼75 nm. SEM images of the nanostructured Nd 0.5 Sr 0.5 MnO 3 powder are presented in [8,9]. X-ray absorption spectra of nanostructured manganites were measured in the surface-sensitive total electron yield mode on a Russian-German line of the BESSY-II storage ring (Berlin) and in the bulk-sensitive fluorescence yield mode on a I511-3 line of the MAX II storage ring (Lund).…”

X-RAY SPECTRA AND CHARGE STATES OF CATIONS IN NANOSTRUCTURED MANGANITES La0,5Ca0,5MnO3 AND Nd0,5Sr0,5MnO3

“…Максимум на распределении частиц по размерам для порошка после размола в течение 8 ч составил ∼75 нм. Изображения наноструктурированного порошка Nd 0,5 Sr 0,5 MnO 3 , полученные с помощью сканирующего электронного микроскопа, приведены в работах [ 8,9 ].…”