The important role of local distortions and their connection with magnetism and transport in the "colossal" magnetoresistance systems, La(1-x)A(x)MnO(3)

Large magnetoresistance (MR) effects have been observed in the substituted systems La(1-x)A(x)MnO(3) (A = Sr, Ca, Ba, Pb, etc.). Most work have been i nterpreted in terms of the double-exchange (DE) model which assumes Mn+3 an d Mn+4 sites exist. Recently Millis has suggested that local distortions, i n the form of polarons, must also be present to explain the magnitude of th e MR. We present X-ray absorption fine structure (XAFS) data which confirm that local distortions are indeed present and show that the distortions are correlated with magnetization. However, the near edge data are not consist ent with charge localization on some of the Mn sites; all Mn appear to have the same average valence.