Percolative transition on ferromagnetic insulator manganites: Uncorrelated to correlated polaron clusters

abstract

We report an atomic-scale study on the ferromagnetic insulator manganite LaMnO3.12 using gamma-gamma perturbed angular correlation spectroscopy. Data analysis reveals a nanoscopic transition from an undistorted to a Jahn-Teller (JT) distorted local environment upon cooling. The percolation thresholds of the two local environments enclose a macroscopic structural transition (rhombohedral-orthorhombic). Two distinct regimes of JT distortions were found: a high-temperature regime where uncorrelated polaron clusters with severe distortions of the Mn3+O6 octahedra survive up to T approximate to 800 K and a low-temperature regime where correlated regions have a weaker JT-distorted symmetry.

keywords

ANGULAR-CORRELATIONS; PEROVSKITE; LAMNO3+/-DELTA; LAMNO3+DELTA; DISORDER; ORDER; MODEL

subject category

Physics

authors

Lopes, AML; Araujo, JP; Ramasco, JJ; Amaral, VS; Suryanarayanan, R; Correia, JG

our authors

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