Wydarzenia

Seminarium Międzynarodowego Laboratorium Silnych Pól Magnetycznych i Niskich Temperatur PAN

Magnetoelectric effect and influence of light on the magnetoelectric effect in diamagnetic sillenites

Krzysztof Filar, Grzegorz Gajda, Victor I. Nizhankovskii

International Laboratory of High Magnetic Fields and Low Temperatures

The magnetoelectric effect - an electric polarization induced by a magnetic field - is observed in ferromagnetic or, at least, paramagnetic structures [1,2]. But if an elementary cell is non-centrosymmetrical then it’s possible to see the magnetoelectric effect even in a diamagnetic crystal [3]. Such observations haven’t been published till now. Moreover, single-crystalline sillenites exhibit the pronounced photorefractive effect, so in our research were seen change of a sign in the magnetoelectric effect as the response to illumination of the sample using light-emitting diodes. Measurements were done for Bi12TiO20 (BTO), Bi12SiO20 (BSO) and Bi12GeO20 (BGO) single crystals, that have non-centrosymmetrical cubic structure and they belong to the I23 space group [4]. The BTO was doped with chromium at level of 0.0015 wt%, whereas BSO and BGO were pure crystals.

[1] M. Fiebig, V.V. Eremenko and I.E. Chupis, “Magnetoelectric Interaction Phenomena in Crystals”, NATO Science Series, II. Mathematics, Physics and Chemistry - vol. 164, Kluwer Academic Publishers, (2004).
[2] W. Eerenstein, N. D. Mathur & J. F. Scott, “Multiferroic and magnetoelectric materials”, Nature, Vol. 442, (2006).
[3] H. Schmid, “Some symmetry aspects of ferroics and single phase multi-ferroics”, J. Phys.: Condens. Matter 20 (2008) 434201.
[4] S. C. Abraiiams, P. B. Jamieson, and J. L. Bernstein, “Crystal Structure of Piezoelectric Bismuth Germanium Oxide Bi 12GeO 20”, J. Chem. Phys. v.47 4034 (1967).