Stability of charge ordering in La0.5−xHoxCa0.5MnO3 polycrystalline manganites

Magnetotransport properties of La 0.5−x Ho x Ca 0.5 MnO 3 ( x = 0.05 and 0.1) polycrystalline samples were investigated in order to study the effect of magnetic Ho 3+ ions on the stability of the charge ordering (CO) and magnetic phase coexistence in pristine La 0.5 Ca 0.5 MnO 3 . Our samples were synthesized by using solgel method. Temperature dependence of resistivity shows an insulating behavior with high resistivity values, confirming the presence of long-range CO. The application of 7 T magnetic field slightly reduces resistivity values and demonstrates relatively small magnetoresistance (MR) values (−MR(T) did not exceed 14% under 7 T applied field). This observation indicates that the CO in the Ho-based specimens is strong, which indicates that Ho substitution for La in La 0.5 Ca 0.5 MnO 3 gives more strength to the CO.