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.

arXiv commentaccepted for publication in Phys. Rev. B (rapid comm.)

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• Magnetic spin excitations in diluted ferromagnetic systems: the case of $G{a}_{1-x}M{n}_{x}As$
• Evolution of Griffiths Phase and Critical Behaviour of La1-xPbxMnO3+-y Solid Solutions
• 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
• Antiferromagnetic rare region effect in $P{r}_{0.5}C{a}_{0.5}Mn{O}_3$
• Optical conductivity of Mn doped GaAs
• Evidence for strong effect of quenched correlated disorder on phase separation and magnetism in (La_{1-y}Pr_{y})_{0.7}Ca_{0.3}MnO_3
• Reconsidering the possibility of room temperature ferromagnetism in Mn doped Zirconium oxide
• Disorder-induced orbital ordering in doped manganites
• On the reliability of recent Monte Carlo studies of dilute systems of localized spins interacting with itinerant carriers
• Griffiths like Robust Ferromagnetism in Co3-xMnxTeO6; (x = 0.5, 1, 2)