Spin polarons in the double-exchange model

Xindong Wang, Arthur J Freeman

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

We consider the possible formation of spin polarons in the double exchange model at finite temperatures. We show that the average size of a spin polaron in this model increases as the temperature decreases. Based on this, we argue that the transition to the ferromagnetic phase in the double-exchange model happens when the spin polarons start overlapping. The effect of the external field is shown to reduce the effective temperature and thus to increase the size of the polarons. The theory predicts a linear increase of Tc versus the applied external magnetic field, a temperature dependence of the magnetic susceptibility above Tc that deviates from Curie-Weiss behavior, and an increase of Tc as the electron/hole density increases.

Original languageEnglish
Pages (from-to)103-105
Number of pages3
JournalJournal of Magnetism and Magnetic Materials
Volume171
Issue number1-2
Publication statusPublished - Jul 1997

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Polarons
polarons
Gene Conversion
Temperature
temperature
Magnetic susceptibility
magnetic permeability
temperature dependence
Magnetic fields
magnetic fields
Electrons

Keywords

  • Double exchange
  • Spin polaron

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Spin polarons in the double-exchange model. / Wang, Xindong; Freeman, Arthur J.

In: Journal of Magnetism and Magnetic Materials, Vol. 171, No. 1-2, 07.1997, p. 103-105.

Research output: Contribution to journalArticle

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AB - We consider the possible formation of spin polarons in the double exchange model at finite temperatures. We show that the average size of a spin polaron in this model increases as the temperature decreases. Based on this, we argue that the transition to the ferromagnetic phase in the double-exchange model happens when the spin polarons start overlapping. The effect of the external field is shown to reduce the effective temperature and thus to increase the size of the polarons. The theory predicts a linear increase of Tc versus the applied external magnetic field, a temperature dependence of the magnetic susceptibility above Tc that deviates from Curie-Weiss behavior, and an increase of Tc as the electron/hole density increases.

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