Exploiting B-site disorder for phase control in the manganites

Harish-Chandra Research Institute - Chhatnag Road, Jhusi, Allahabad 211019, India

Corresponding author: pinaki@mri.ernet.in

Received: 10 July 2008
Accepted: 24 September 2008

Abstract

Disorder on the active d element site is usually very disruptive for conduction and long-range order in perovskite transition metal oxides. However, in the background of phase competition such “B-site” dopants also act to promote one ordered phase at the expense of another. This occurs either through valence change of the transition metal or via creation of “defects” in the parent magnetic state. We provide a framework for understanding the complex variety of phenomena observed in B-sitedoped manganites and identify the key parameters that control the physics. Using a spatially resolved analysis of B ions in various manganite phases we explain the existing data and predict new situations where highly polarisable phase separated states can be created.