Effects of correlated disorder on the magnetism of double exchange systems

Abstract

We study the effects of short-range correlated disorder arising from chemical dopants or local lattice distortions, on the ferromagnetism of 3d double exchange systems. For this, we integrate out the carriers and treat the resulting disordered spin Hamiltonian within local random phase approximation, whose reliability is shown by direct comparison with Monte Carlo simulations. We find large scale inhomogeneities in the charge, couplings and spin densities. Compared with the homogeneous case, we obtain larger Curie temperatures ($T_C$) and very small spin stiffnesses ($D$). As a result, large variations of $\frac{D}{T_C}$ measured in manganites may be explained by correlated disorder. This work also provides a microscopic model for Griffiths phases in double exchange systems.

accepted for publication in Phys. Rev. B (rapid comm.)

References in corpus (5)

• Critical behavior of Griffiths ferromagnets
• Coulomb Interactions and Nanoscale Electronic Inhomogeneities in Manganites
• Monte Carlo Study of Doping Change and Disorder Effect on Double Exchange Ferromagnetism
• Disorder-Induced First Order Transition and Curie Temperature Lowering in Ferromagnatic Manganites
• Domain Formation and Orbital Ordering Transition in a Doped Jahn-Teller Insulator

Cited by in corpus (7)

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• Magnetic spin excitations in diluted ferromagnetic systems: the case of $G{a}_{1-x}M{n}_{x}As$
• Flat band induced room temperature ferromagnetism in two dimensional systems
• Magnetic and Orbital Order in ($R$MnO${}_3$)${}_n$/($A$MnO${}_3$)${}_{2n}$ Superlattices Studied via a Double-Exchange Model with Strain
• Selective substitution in orbital domains of a low doped manganite : an investigation from Griffiths phenomenon and modification of glassy features
• Dynamical properties of a three-dimensional diluted Heisenberg model
• Disorder-induced orbital ordering in doped manganites