中国物理B ›› 2002, Vol. 11 ›› Issue (12): 1303-1306.doi: 10.1088/1009-1963/11/12/316

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A possible coupling mechanism between magnetism and dielectric properties in EuTiO3

蒋青, 吴华   

  1. Department of Physics, Suzhou University, Suzhou 215006, China
  • 收稿日期:2002-05-30 修回日期:2002-08-18 出版日期:2002-12-12 发布日期:2005-06-12

A possible coupling mechanism between magnetism and dielectric properties in EuTiO3

Jiang Qing (蒋青), Wu Hua (吴华)   

  1. Department of Physics, Suzhou University, Suzhou 215006, China
  • Received:2002-05-30 Revised:2002-08-18 Online:2002-12-12 Published:2005-06-12

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摘要： The dielectric constant of an incipient ferroelectric EuTiO3 exhibits a sharp decrease at about 5.5K, at which the antiferromagnetic ordering of the Eu spins simultaneously appears. This fact indicates the existence of a coupling between the magnetism and dielectric properties of EuTiO3. We propose a possible coupling mechanism between the magnetic and electrical subsystems as -g\dsuml \dsum〈i,j〉q2l\vec Si·\vec Sj. In the framework of soft-mode theory, we have obtained analytically a dielectric constant expression related to the spin correlation of nearest neighbours of Eu ions.

Abstract: The dielectric constant of an incipient ferroelectric EuTiO3 exhibits a sharp decrease at about 5.5K, at which the antiferromagnetic ordering of the Eu spins simultaneously appears. This fact indicates the existence of a coupling between the magnetism and dielectric properties of EuTiO3. We propose a possible coupling mechanism between the magnetic and electrical subsystems as $-g\sum_l\sum_{\langle i,j \rangle}q_l^2\vec{S}_i\cdot\vec{S}_j$. In the framework of soft-mode theory, we have obtained analytically a dielectric constant expression related to the spin correlation of nearest neighbours of Eu ions.

Key words: coupling mechanism, magnetism, dielectric property, soft-mode theory

中图分类号:  (Dielectric, piezoelectric, ferroelectric, and antiferroelectric materials)

  • 77.84.-s
77.22.Ch (Permittivity (dielectric function)) 75.50.Ee (Antiferromagnetics) 75.10.Dg (Crystal-field theory and spin Hamiltonians)