Crystal Structure and Magnetic Properties of Cu-Substituted La0.90Ag0.10MnO3 Compounds

In the present work, a series of (La0.90Ag0.10)(Mn1-yCuy)O-3 compounds (y = 0-0.20) have been prepared by solid-state reaction route to study the influence of Cu substitution at Mn site of (La0.90Ag0.10)MnO3 compound on crystal structure and magnetic property. From the refinement of XRD patterns, it is found that no significant structural change has taken place by Cu substituion and all compounds are found to crystallize to rhombohedral structure (R (3) over barc space group). However, it is observed that the Cu substitution into (La0.90Ag0.10)MnO3 compound has led to a drastic decrease of ferromagnetic (FM) transition temperature (T-C), from 245.8 K for y = 0 to 174.3 K for y = 0.20 compound. The reduction of FM T-C has been explained in terms of dilution of double exchange interaction across Mn3+-O2--Mn4+ networks. The measurement of magnetization data under zero field cooling and field cooled warming conditions exhibits strong magnetic irreversibility, which is explained in terms of domain wall pinning. The hysteresis (M-H) curves measured for these compounds at 5 K indicate that the magnetization was found to saturate even at very low field and the value of saturation magnetization (M-S) is found to decrease with increase in Cu doping and it is in correlation with theoretically estimated value of saturation magnetization. The measurement of Arrott plots (M-2 versus H/M) for 10, 15, and 20% Cu-doped compounds indicates that these compounds exhibit second-order magnetic phase transition.