Structure and Properties of Nd_(0.67)(Sr,Ca)_(0.33)Mn(O,F)_3 with Colossal Magnetoresistance

Compounds of Nd0.67(Sr,Ca)0.33Mn(O,F)3 (NSMO) with colossal magnetoresistance (CMR)were prepared with CaF2 as dopant. X-ray diffraction with Rietveld analysis showed that NSMO compounds were of perovskite structures, with space groups of Pbnm, Z=4, and F- occupying 8d positions. As more amount of CaF2 were used, the lattice parameters and To of NSMO declined.The magnetoresistance (-△R/R) increased to a maximum of 99.7% when 20mol% CaF2 was doped.