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

Magnetotransport properties of La0.5−xHoxCa0.5MnO3 (x = 0.05 and 0.1) polycrystalline samples were investigated in order to study the effect of magnetic Ho3+ ions on the stability of the charge ordering (CO) and magnetic phase coexistence in pristine La0.5Ca0.5MnO3. 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 La0.5Ca0.5MnO3 gives more strength to the CO.