Magnetoelectric behavior in the complex CaMn7O12 perovskite

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:321

Article; Proceedings Paper

Sanchez-Andujar, M.¹  Yanez-Vilar, S.¹  Biskup, N.²  Castro-Garcia, S.¹  Mira, J.³  Rivas, J.³  Senaris-Rodriguez, M. A.¹ 

[1] Univ A Coruna, Fac Ciencias, Dept Quim Fundamental, La Coruna 15071, Spain

[2] CSIC, Inst Ciencias Mat, E-28049 Madrid, Spain

[3] Univ Santiago de Compostela, Dpto Fis Aplicada, Santiago De Compostela 15782, Spain

关键词: Magnetoelectric;    Perovskite;    Charge-ordering;   

DOI  :  10.1016/j.jmmm.2009.02.018

来源: Elsevier

【 摘 要 】

We report a magnetoelectric effect in the double perovskite CaMn7O12, that shows a complex magnetic behavior below 90 K with two magnetic phases coexisting (one ferrimagnetic and the other modulated). A second magnetic transition, associated with changes in the magnetic modulation and magnetic ordering coherence lengths of the two magnetic phases occurs at 50 K (T-N2). A detailed structural characterization of this compound, that we have carried out by means of high-resolution X-ray powder diffraction, reveals an anisotropic thermal expansion of its lattice parameters at 50 K (T-N2). In addition, our study of the complex permittivity of this sample as a function of temperature, frequency and magnetic field shows very interesting results below 90 K and specially below 50 K: the dielectric constant epsilon'(r) that was decreasing continuously on cooling experiences an upturn, and even more, on application of a magnetic field it shows a moderate magnetoelectric response. We attribute such dielectric behavior to the formation of electric dipoles by magnetostriction in this charge and spin ordered system, that are sensible to the presence of an external magnetic field. (C) 2009 Elsevier B.V. All rights reserved.

【 授权许可】

Free