Universal relationship between magnetization and changes in the local structure of La1-xCaxMnO3: evidence for magnetic dimers

• Published in: Physical review letters Vol. 95; no. 10; p. 106401
• Main Authors: Downward, L, Bridges, F, Bushart, S, Neumeier, J J, Dilley, N, Zhou, L
• Format: Journal Article
• Language: English
• Published: United States 02.09.2005
• ISSN: 0031-9007
• DOI: 10.1103/PhysRevLett.95.106401

We present extensive x-ray absorption fine structure measurements on La(1-x)Ca(x)MnO(3) as a function of the B field (to 11 T) and Ca concentration, chi(21%-45%). These results reveal local structure changes (associated with polaron formation) that depend only on the magnetization for a given sample, irrespective of whether the magnetization is achieved through a decrease in temperature or an applied magnetic field. Furthermore, the relationship between local structure and magnetization depends on the hole doping. A model is proposed in which a filamentary magnetization initially develops via the aggregation of pairs of Mn atoms involving a hole and an electron site. These pairs have little distortion and it is likely that they form at temperature T(*) above T(c).