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Title: Colossal Magnetoresistance Observed in Monte Carlo Simulations of the One- and Two-Orbital Models for Manganites

Abstract

he one- and two-orbital double-exchange models for manganites are studied using Monte Carlo computational techniques in the presence of a robust electron-phonon coupling (but neglecting the antiferromagnetic exchange $$J_{\rm AF}$$ between the localized spins). The focus in this effort is on the analysis of charge transport. Our results for the one-orbital case confirm and extend previous recent investigations that showed the presence of robust peaks in the resistivity vs. temperature curves for this model. Quenched disorder substantially enhances the magnitude of the effect, while magnetic fields drastically reduce the resistivity. A simple picture for the origin of these results is presented. It is also shown that even for the case of just one electron, the resistance curves present metallic and insulating regions by varying the temperature, as it occurs at finite electronic density. Moreover, in the present study these investigations are extended to the more realistic two-orbital model for manganites. The transport results for this model show large peaks in the resistivity vs. temperature curves, located at approximately the Curie temperature, and with associated large magnetoresistance factors. Overall, the magnitude and shape of the effects discussed here closely resemble experiments for materials such as $$\rm La_{0.70} Ca_{0.30} Mn O_{3}$$, and they are in qualitative agreement with the current predominant theoretical view that competition between a metal and an insulator, enhanced by quenched disorder, is crucial to understand the colossal magnetoresistance (CMR) phenomenon.

Authors:
 [1];  [2];  [2];  [2]
  1. Florida State University
  2. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Center for Computational Sciences
Sponsoring Org.:
USDOE Laboratory Directed Research and Development (LDRD) Program; ORNL other overhead
OSTI Identifier:
931279
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review B; Journal Volume: 73
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; MANGANESE OXIDES; CHARGE TRANSPORT; CURIE POINT; ELECTRON-PHONON COUPLING; MAGNETORESISTANCE; MONTE CARLO METHOD; MATHEMATICAL MODELS

Citation Formats

Sen, Cengiz, Alvarez, Gonzalo, Aliaga, Horacio A, and Dagotto, Elbio R. Colossal Magnetoresistance Observed in Monte Carlo Simulations of the One- and Two-Orbital Models for Manganites. United States: N. p., 2006. Web. doi:10.1103/PhysRevB.73.224441.
Sen, Cengiz, Alvarez, Gonzalo, Aliaga, Horacio A, & Dagotto, Elbio R. Colossal Magnetoresistance Observed in Monte Carlo Simulations of the One- and Two-Orbital Models for Manganites. United States. doi:10.1103/PhysRevB.73.224441.
Sen, Cengiz, Alvarez, Gonzalo, Aliaga, Horacio A, and Dagotto, Elbio R. Sun . "Colossal Magnetoresistance Observed in Monte Carlo Simulations of the One- and Two-Orbital Models for Manganites". United States. doi:10.1103/PhysRevB.73.224441.
@article{osti_931279,
title = {Colossal Magnetoresistance Observed in Monte Carlo Simulations of the One- and Two-Orbital Models for Manganites},
author = {Sen, Cengiz and Alvarez, Gonzalo and Aliaga, Horacio A and Dagotto, Elbio R},
abstractNote = {he one- and two-orbital double-exchange models for manganites are studied using Monte Carlo computational techniques in the presence of a robust electron-phonon coupling (but neglecting the antiferromagnetic exchange $J_{\rm AF}$ between the localized spins). The focus in this effort is on the analysis of charge transport. Our results for the one-orbital case confirm and extend previous recent investigations that showed the presence of robust peaks in the resistivity vs. temperature curves for this model. Quenched disorder substantially enhances the magnitude of the effect, while magnetic fields drastically reduce the resistivity. A simple picture for the origin of these results is presented. It is also shown that even for the case of just one electron, the resistance curves present metallic and insulating regions by varying the temperature, as it occurs at finite electronic density. Moreover, in the present study these investigations are extended to the more realistic two-orbital model for manganites. The transport results for this model show large peaks in the resistivity vs. temperature curves, located at approximately the Curie temperature, and with associated large magnetoresistance factors. Overall, the magnitude and shape of the effects discussed here closely resemble experiments for materials such as $\rm La_{0.70} Ca_{0.30} Mn O_{3}$, and they are in qualitative agreement with the current predominant theoretical view that competition between a metal and an insulator, enhanced by quenched disorder, is crucial to understand the colossal magnetoresistance (CMR) phenomenon.},
doi = {10.1103/PhysRevB.73.224441},
journal = {Physical Review B},
number = ,
volume = 73,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}