Fine-tuning of magnetoresistance in Nd/sub 0.5/(Ca,Sr)/sub 0.5/MnO/sub 3/ system

In this work, ionic size or the radius of A-site cation

was utilized for the fine-tuning of the magnetoresistance (MR) of Nd/sub 0.5/Ca/sub 0.5-y/Sr/sub y/MnO/sub 3/. The values of

were set to be from 1.182 /spl Aring/ to 1.20 /spl Aring/. The highest MR ratio was obtained to be /spl sim/ 800% at 50 K in the samples with y = 0.08. Furthermore, the "spin valve" like behavior was observed at 100 K at the same sample, which may have originated from the melting of charge ordering.