Magneto-transport and specific heat behavior of Cd-doped La0.5Ca0.5MnO3

The temperature-dependent magneto-transport properties and the specific heat of La0.5(Ca0.5−xCdx)MnO3 (x=0.0-0.5) are measured for understanding the electronic phase separation behaviors in manganites. It is surprising to observe that Cd-doping enhances the ferromagnetic metallic state and suppresses the insulating state. Two insulator-metal transitions in La0.5(Ca0.3Cd0.2)MnO3 are observed, one occurs at temperature TP1 in accordance with the observed paramagnetic-ferromagnetic transition point TC and the other appears at a lower temperature TP2. The magnetoresistance of La0.5(Ca0.3Cd0.2)MnO3 as a function of temperature shows a sharp peak around TC, and remains roughly unchanged over a wide temperature range below TP1. It is argued that these fantastic properties are attributed to the coexistence of ferromagnetic metallic state and ferromagnetic insulating state under an antiferromagnetic background due to the Cd-doping effect.