Abstract
High real-space-resolution atomic pair distribution functions of 0.25, and 0.33) have been measured using high-energy x-ray powder diffraction to study the size and shape of the octahedron as a function of temperature and doping. In the paramagnetic insulating phase we find evidence for three distinct bond lengths which we ascribe to -short, and -long bonds, respectively. In the ferromagnetic metallic (FM) phase, for and we find a single Mn-O bond length; however, as the metal-insulator transition is approached either by increasing T or decreasing x, intensity progressively appears around and in the region suggesting the appearance of -long bonds and short bonds. This is strong evidence that charge localized and delocalized phases coexist close to the metal-insulator transition in the FM phase.
- Received 21 July 1999
DOI:https://doi.org/10.1103/PhysRevB.62.1203
©2000 American Physical Society