Nanocomposites and nanomaterials

Magnetoelectric coupling in ferrimagnetic/piezoelectric composite structure
Koronovskyy V.E., Vakyla Y.O.
Taras Shevchenko Kiev National University, 4-g, Prospekt Glushkova Street, 03127 Kiev, Ukraine
E-mail: koron@univ.kiev.ua

The magnetoelectric (ME) coupling was demonstrated in a ferrimagnetic/piezoelectric composite structure by using optical polarimetry method. This method allows us to measure a change of light polarization plane Faraday rotation (αME) in our structures in an external electric field [1]. The investigated sample is the two-phase structure with mechanically stuck together thin magnetostriction (epitaxial film of bismuth-substituted ferrite garnet) and a piezoelectric (lead zirconate titanate (PZT)) plates. The investigated structure exhibits a αME value changes as a magnetoelectric response for garnet film by applying an external variable electrical field (E = 0 - 3,5 kV/cm) to both garnet film and PZT phases. Electric field (ϖ = 800 Hz) was applied perpendicular to the sample plane. A He-Ne laser (λ = 0.63 µm) was used in the experiment. Piezoelectric phase in given structure carries out amplifier function for ME effect already induced by electric field in thin epitaxial garnet film (thickness of the film was about 9 μm). We register the ME parameter (αME) as a total result of two effects - the ME effect in the garnet film and the ME effect due to mechanical conjugation of magnetic and piezoelectric phases. This effect for composite structure went up essentially (by a factor approximately of eight) than ME effect for separate magnetic (ferrite garnets) phase [2,3]. The value of the ME effect is dependent on the volumes of the piezoelectric and magnetostrictive phases.

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