Theory of half-metallic double perovskites. II. Effective spin Hamiltonian and disorder effects

Onur Erten, O. Nganba Meetei, Anamitra Mukherjee, Mohit Randeria, Nandini Trivedi, Patrick Woodward

Research output: Contribution to journalArticle

38 Scopus citations

Abstract

Double perovskites such as Sr2FeMoO6 are materials with half-metallic ground states and ferrimagnetic Tc's well above room temperature. This paper is the second of our comprehensive theory for half-metallic double perovskites. Here we derive an effective Hamiltonian for the Fe core spins by "integrating out" the itinerant Mo electrons and obtain an unusual double-square-root form of the spin-spin interaction. We validate the classical spin Hamiltonian by comparing its results with those of the full quantum treatment presented in a companion paper. We then use the effective Hamiltonian to compute magnetic properties as a function of temperature and disorder and discuss the effect of excess Mo, excess Fe, and antisite disorder on the magnetization and Tc. We conclude with a proposal to increase Tc without sacrificing carrier polarization.

Original languageEnglish (US)
Article number165105
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume87
Issue number16
DOIs
StatePublished - Apr 4 2013
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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