VARIATION OF THE JAHN-TELLER DISTORTION O F MN AT THE FERROMAGNETIC TRANSITION IN THE CMR PEROVSKITE PR0.7CA0.2SR0.1MNO3

The determination of the structure of the CMR perovskite Pr0.7Ca0.2Sr0 .1MnO3, at different temperatures from 1.7 to 293 K, from powder neutr on diffraction data has allowed the ''O-3'' stoichiometry to be establ ished and a significant contraction of the lattice parameters at the f erromagnetic transition. But the most remarkable feature deals with th e decrease of the Jahn Teller distorsion that coincides exactly with t he transition temperature, showing strong correlations between the Jah n Teller effect and the magnetic ordering of manganese in the CMR pero vskite.