The Rietveld analysis of the room temperature x-ray diffraction patterns confirms no observable change in average crystal structure with

the La substitution. Both magnetic and magnetotransport properties are found to be very sensitive to the La substitution. Interestingly, the La-substituted compounds show ferromagneticlike behavior (due to the occurrence of a double exchange mechanism), whereas the parent compound is an antiferromagnet (T-N similar to 150 K). All compounds show an insulating behavior in the measured temperature range of 100-300 PF 477736 K, with an overall decrease in the resistivity with the substitution. A higher value of magnetoresistance has been successfully achieved by the La substitution. We have proposed an electronic phase separation model, considering the formation of ferromagnetic clusters in the antiferromagnetic matrix, to interpret the observed magnetization and magnetotransport results for the La-substituted samples. The present study demonstrates an approach to achieve new functional materials, based on naturally occurring layered system like Ca2.5-xLaxSr0.5GaMn2O8, for possible spintronics applications.”
“The composite microspheres of poly(lacrylamide) microgels (PAM) surfacely covered with [2-(methacryloyloxy)ethyl]dodecyldimethylammonium (MEDDAB)tungstophosphate

(HPW) complexes (MEDDAB-HPW) were synthesized by using ion-exchange reaction between MEDDAB Blebbistatin mw located within the porous PAM microgels and HPW in aqueous solution. The morphology and component of the composite microspheres were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis, respectively. The results indicated that PAM/MEDDAB-HPW composite microsphere with different hierarchical surface structures could be obtained by controlling the

weight ratio of MEDDAB to HPW in the microgels and cross-linking degree of PAM microgels. Although the surface morphologies of the composite microspheres prepared in different conditions were different, a selleck kinase inhibitor general feature was that the composite microspheres have the core-shell structure and the wrinkly surface covered with the particles of MEDDAB-HPW complexes. The formation of the wrinkly surface is attributed to the difference in shrinkage between inside and outside of PAM microgel frameworks due to deposition of MEDDAB-HPW on the surface, and the formation of MEDDAB-HPW small particles originates from the reaction between MEDDAB aggregation and HPW. For this composite microsphere, PAM hydrogel core is suitable to store water-soluble substances, and the shell composed of the surfactant/Keggin-type polyoxometalate complexes is not only amphiphilic but also catalytic. Additionally, PAM/MEDDAB-HPW composite microspheres with big size and MEDDAB-HPW particles with small size make the composite microspheres not only easy for separation but also beneficial for catalysis.