Effect of electron correlation in Sr(Ca)Ru{sub 1-x}Cr{sub x}O{sub 3}: Density functional calculation

Journal Article · Thu Jul 15 00:00:00 EDT 2010 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2010.05.013· OSTI ID:21421562

Hadipour, H ^[1]; Akhavan, M ^[1]

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1. Magnet Research Laboratory (MRL), Department of Physics, Sharif University of Technology, P.O. Box 11365-9161, Tehran (Iran, Islamic Republic of)

We have investigated the electronic structure of Sr(Ca)Ru{sub 1-x}Cr{sub x}O{sub 3} using the full potential linearized augmented plane wave method by different approximation such as LSDA and LSDA+U. The LSDA calculation suggest that Cr{sup 4+}-Ru{sup 4+} hybridization is responsible for the high Curie temperature T{sub C} in SrRu{sub 1-x}Cr{sub x}O{sub 3}, but it cannot completely describe its physical behavior. Our LSDA+U DOS results for SrRu{sub 1-x}Cr{sub x}O{sub 3} clearly establishes renormalization of the intra-atomic exchange strength at the Ru sites, arising from the Cr-Ru hybridization. The antiferromagnetic coupling of Cr{sup 3+} with Ru{sup 4+,5+} lattice increases the screening, which is consistent with the low magnetic moment of the Ru ions. The more distorted Ca-based compounds as compared to the Sr-based systems shows that the hybridization mechanism is not relevant for these compounds. The bigger exchange splitting of Ru 4d and Cr 3d at the Fermi level with Ru{sup 4+,5+} and Cr{sup 3+,4+} orbital occupancies of CaRu{sub 0.75}Cr{sub 0.25}O{sub 3} in the LSDA+U calculation, compared with that of the LSDA calculation, shows that repulsion between electrons tend to keep the localized spins from overlapping. The low screening of the Ru t{sub 2g} electrons increases T{sub C} in the Ca-based systems, which is consistent with the both high Ru exchange splitting and magnetic moment. The insulating behavior of the high Cr-doped systems can be explained by considering the Ru{sup 4+}+Cr{sup 4+{yields}}Ru{sup 5+}+Cr{sup 3+} charge transfer. - Graphical Abstract: We have investigated the electronic structure of Sr(Ca)Ru{sub 1-x}Cr{sub x}O{sub 3} using different ab-initio calculation such as LSDA and LSDA+U approximation. The antiferromagnetic hybridization of Cr{sup 3+} with Ru{sup 4+,5+} lattice increases the screening, which is consistent with the low magnetic moment of the Ru ions. The LSDA+U calculation for the more distorted Cr impurity doped Ca-based ruthenate compounds as compared to the Sr-based systems shows repulsion between electrons, which tends to keep the localized spins from overlapping.

• OSTI ID: 21421562
• Journal Information: Journal of Solid State Chemistry, Vol. 183, Issue 7; Other Information: DOI: 10.1016/j.jssc.2010.05.013; PII: S0022-4596(10)00202-1; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANTIFERROMAGNETISM
CALCIUM COMPOUNDS
CHROMIUM COMPOUNDS
CHROMIUM IONS
COUPLING
CURIE POINT
DENSITY FUNCTIONAL METHOD
DOPED MATERIALS
ELECTRON CORRELATION
ELECTRONIC STRUCTURE
FERMI LEVEL
FERROMAGNETIC MATERIALS
HYBRIDIZATION
MAGNETIC MOMENTS
OXYGEN COMPOUNDS
RUTHENIUM COMPOUNDS
RUTHENIUM IONS
STRONTIUM COMPOUNDS
WAVE PROPAGATION
ALKALINE EARTH METAL COMPOUNDS
CALCULATION METHODS
CHARGED PARTICLES
CORRELATIONS
ENERGY LEVELS
IONS
MAGNETIC MATERIALS
MAGNETISM
MATERIALS
PHYSICAL PROPERTIES
REFRACTORY METAL COMPOUNDS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
VARIATIONAL METHODS