CHEMICAL DISORDER AND CHARGE-TRANSPORT IN FERROMAGNETIC MANGANITES

Disorder broadening due to randomly distributed La3+ and A(2+) (A=Ca,S r,Ba) cations is combined with a virtual-crystal treatment of the aver age system to evaluate the effects on both majority and minority trans port in the ferromagnetic La(2/3)A(1/3)MnO(3) system. The low-density minority carriers which lie in the band tail are localized by disorder , while the majority carriers retain long mean free paths reflected in the observed strongly metallic conductivity. In addition to obtaining transport parameters, we provide evidence that local distortions are due to nearby ionic charges rather than to ion size considerations.