Nanocomposites and nanomaterials

Visualization of magneto-electric interactions in micro-magnetic structural elements of garnet films
Koronovskyy V.E., Vakyla Y.A.
Taras Shevchenko Kyiv National University, 4-g, Prospekt Glushkova Street, 03127 Kyiv, Ukraine
E-mail: koron@univ.kiev.ua

Micro-magnetic structural elements of magnetic domains in ferromagnetics (magnetic domain walls (DW), vertical Bloch lines and Bloch points) are attracting a sustained interest both from a fundamental perspective and for applications. At the same time, the reports about the development of new techniques to manipulate magnetization by electric field are known, which provide new prospects for magnetic memory technologies. One of the most acceptable methods for such investigations may be magneto-optical method [1,2]. Magneto-electric (ME) properties of structural elements of epitaxial films of ferrite-garnets have been investigated by us using the optical polarimetry method and method of optical dark field microscopy. These methods allows us to measure the change of light polarization plane rotation (λ=0.63 µm) in an electric field and the method of optical dark field allowed us to take measurements with the direct visual observations. In our experiment we used bismuth-substituted ferrite garnet ﬁlm grown by liquid-phase epitaxy on (210) Gd3Ga5O12 substrate. Thickness of the ﬁlm was about 8 µm range. Investigated film was placed between two optically transparent electrodes and electric field was applied to them. The geometry of experiments: H||E||k, where k is a light wave vector, H is a magnetic field and E is an electric field. Small impact of E-field on the distribution of the magnetization in investigated film (ME effect) was observed in presented experimental conditions. When we use the combined impact on the film by two influence channels - AC electric fields and constant magnetic field, the small near-surface displacements (distortions) of the DW profile of separate sections of the DW are detected. In our opinion, similar reaction of the domain structure was caused by changing the magnetic anisotropy parameters of the film in an electric field.

1.	Koronovskyy V., Ryabchenko S., and Kovalenko V. Electromagneto-optical
effects on local areas of ferrite-garnet film // Phys Rev B.-2005.-71.-P. 172402-172405.
2.	Koronovskyy V., Vakyla Y. Magneto-electric response of iron garnet film micromagnetic structure on combined action of AC and DC electric field // Electronic Materials Letters.-2015.- 11.-P.1028-1032.