Structural and Transport Properties for Al- and Fe-Doping La_0.67Ca_0.33MnO₃ Perovskite Manganese

The effects of Al and Fe ion doping in Mn sites was studied for the colossal La_0.67Ca_0.33MnO₃ magnetoresistance material. It was found that when the Fe-doping amount x increases, the crystal cell structure has no obvious change, but the crystal cell volume decrease monotonically for Al-doping. Both resistances increase rapidly and the insulator-metal transition temperature moves to lower temperature and decreases linearly with Al-doping. The area for Al-doping is broader than Fe. At small amount of Al-doping, the resistance satisfy the metal transport property when T < T_IM. The characteristic of the transport behaviour for Al- and Fe-doping can be explained by terminating the double exchange channel of Mn³⁺-O^2--Mn⁴⁺.