Hyperfine fields at the Cd site in La 0.67Cd 0.25MnO3 CMR manganites

Although Cd and Ca ions have the same valence and cation size, their incorporation into vacancy doped La manganites induce different properties. While the incorporation of Ca leads to high Tc up to 250 K and induces a metallic-like behaviour, the incorporation of Cd severely reduces Tc and promotes insulator-like behaviour. In this work, the Cd hyperfine fields have been measured with the Perturbed Angular Correlations (PAC) technique after implantation and annealing of $^{111m}$Cd in La-Cd-MnO$_3$ samples. The PAC results are compared with measurements of the resistivity and magnetisation performed on the same samples. The mixed La and Mn site Cd occupancy is suggested as a possibility to explain the properties of the La-Cd-MnO$_3$ system.