Mössbauer Effect Probe of Local Jahn-Teller distortion in Fe-doped Colossal Magnetoresistive Manganites

Local structure of the Fe-doped La1−xCaxMnO3 (x=0.00-1.00) compounds has been investigated by means of Mössbauer spectroscopy. 57Fe Mössbauer spectra provide a direct evidence of Jahn-Teller distortion in these manganites. On the basis of Mössbauer results, the Jahn-Teller coupling was estimated. It is noteworthy that Ca-concentration dependence of Jahn-Teller coupling strength is very consistent with the magnetic phase diagram. Our results reveal that Mössbauer spectroscopy can not only detect the local structural distortion, but also provide a technique to investigate Jahn-Teller coupling of Fe-doped La1−xCaxMnO3 colossal magnetoresistive perovskites. PACS: 61.10.-i; 76.80.+y; 75.30. Vn *Corresponding author Typeset using REVTEX 1 The discovery of colossal magnetoresistance (CMR) in the manganese perovskites La1−xCaxMnO3 has recently attracted significant scientific attention. 1,2 More and more evidence has indicated that the double-exchange coupling model alone is not sufficient to explain the CMR effect, and strong electron-lattice coupling plays an important role in determining the observed resistivity behavior and the magnetic transition temperature. 3−7 Millis has argued that there are two types of lattice effects in ABO3-type magnetoresistive manganese perovskites. 7 One is the tolerance factor, t =