Abstract: In order to further enhance resistance transition temperature (Tp) of metal-semiconductor of La-Ca-Mn-O colossal magnetoresistance ceramics, La_(0.67)Ca_(0.33)MnO_3 (LCMO) polycrystalline ceramics were formed as cylindrical pellets (φ13 mm×8 mm) by conventional solid-state reaction method. The anisotropy of LCMO samples which was cut from the sections parallel and perpendicular to the pressing direction were studied, respectively. The R-T curves shows that transition temperatures for these two types of specimens were 177 K and 261 K, respectively under and 0.5 T magnetic field. In addition, the mechanism of dramatic enhancement of transition temperature was explained through investigating XRD and SEM of the specimens.

Key words: In order to further enhance resistance transition temperature (Tp) of metal-semiconductor of La-Ca-Mn-O colossal magnetoresistance ceramics, La_(0.67)Ca_(0.33)MnO_3 (LCMO) polycrystalline ceramics were formed as cylindrical pellets (φ13 mm×8 mm) by conventional solid-state reaction method. The anisotropy of LCMO samples which was cut from the sections parallel and perpendicular to the pressing direction were studied, respectively. The R-T curves shows that transition temperatures for these two types of specimens were 177 K and 261 K, respectively under and 0.5 T magnetic field. In addition, the mechanism of dramatic enhancement of transition temperature was explained through investigating XRD and SEM of the specimens.