Nanocomposites and nanomaterials

Vertical Bloch lines dynamics in ferrite-garnet films under electric field
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

In this paper, we present the results from study of the magnetization dynamics for the vertical Bloch lines (VBL) within a twisted Bloch domain walls (DW) of ferrite-garnets epitaxial films. One of the acceptable methods for such investigations may be magneto-optical method [1,2]. In our experiments we used the method of optical dark-field microscopy, which allows us to take the direct visual observations for DW's and this method is very sensitive to the domain wall deformation [3]. In particular, a DW deformation occurs in the vicinity of a VBL’s for magnetostatic reasons. Pre-acquired anisotropic-dark-field optical imaging is shown to reveal the presence of VBL’s in the domain walls of ferrite garnets films.
In our experiments we used epitaxial ferrite-garnet ﬁlms grown by liquid-phase epitaxy on non-magnetic Gd3Ga5O12 substrates. Thickness of the ﬁlms was 6,5-9 µm range and thickness of the substrates for ﬁlms was about 600 µm. The investigated samples were placed between optically transparent electrodes and external electric field was applied to them. Wherein the electric field was oriented perpendicular to the plane of the film. We revealed the magnetoelectric activity effect of VBL's in garnet film in external electric field with the direct visual observations. Effect visually manifested as a delocalization of the regions of VBL's and this effect is especially visible when we use the combined impact on the film by two influence channels - AC electric field and DC electric field.

1.	Koronovskyy V., Ryabchenko S., and Kovalenko V. Electromagneto-optical
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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.
3.	A. Thiaville, J. Ben Youssef, Y. Nakatani, J. Miltat. On the influence of wall microdeformations on Bloch line visibility in bubble garnets (invited) // J. Appl. Phys.-1991.-69.-P.6090-6095.