纳米级Sr_2FeMoO_6/CeO_2复合材料磁致电阻效应研究

Enhanced low-field magnetoresistance in nanostructured Sr_2FeMoO_6/CeO_2 composites

研究具有纳米级晶粒尺寸的(Sr_2FeMoO_6)_(1-x)/(CeO_2)_x复合材料的电输运性质.发现其低场磁致电阻效应在整个温区内要高于纯Sr_2FeMoO_6多晶材料.外加磁场为2 kOe(1 Oe=1000/(4π)A/m时,x=0.3的复合材料在10K与300 K的磁致电阻分别为纯SFMO样品的1.7与1.3倍.表明载流子在晶界处的隧穿效应加强了其磁致电阻效应.

The electric transport properties of the nanostructrued（Sr2FeMoO6）（1-x）/（CeO2）（？） composition were investigated.It was found that the low-field magnetoresistance of the composition is higher than that of the pure Sr2FeMoO6 material in the whole region of temperature.The magnetoresistance ratios at 10 K and 300 K with H=2 kOe for the x=0.3 sample are 1.7 times and 1.3 times as large as that for the pure Sr2FeMoO6,respectively.This means that the spindependent tunneling at the interfaces of grain boundaries is responsible for the enhanced MR.