Charge reallocation in the tetragonal to monoclinic transition in Pr1/2SR1/2MnO3

The structural changes associated with the ferromagnet-ic (FM) metallic-to- antiferromagnetic (AFM) insulating transition of Pr1/2Sr1/2MnO3 (I4/mcm --> P2(1)/n) have been analysed by means of high-resolution neutron diffractio n data. Mn positions in the low-temperature phase have the same charge and identically deformed octahedra. The transition is the result of a stretchin g-like distortion of the octahedra that (i) contracts the Mn-O bond perpend icular to the FM planes by deviating beta from 90 degrees C and (ii) inject s electrons into in-plane Mn-O bonds (C) 2000 Elsevier Science B.V. All rig hts reserved.