Enhanced room-temperature magnetoresistance in La0.7Sr0.3MnO3-glass composites

In this letter, we report the improved magnetotransport properties of La0.7 Sr0.3MnO3-borosilicate glass composite with different weight percents of gl ass. All the composites showed ferromagnetic nature at room temperature. Th e microstructure of these composites was seen using a scanning electron mic roscope. The microstructure was reconfirmed using spot energy dispersive x- ray analysis. We observe an enhancement of the low-field magnetoresistance (< 200 Oe) at room temperature for the optimal composition of 25 wt % of gl ass. It is argued that glass layer separating the grain boundaries may be a cting as barrier for spin-polarized tunneling, thereby enhancing the low-fi eld magnetoresistance. (C) 2001 American Institute of Physics.