Nanocomposites and nanomaterials

Influence of an external electric field on sub-structural nano-formations of domain walls in ferrite garnet films
Koronovskyy V.E., Vakyla Y.A.
Taras Shevchenko Kyiv National University, Faculty of Radiophysics, Electronics and Computer Systems
4-g, Prospekt Glushkova Street, 03127 Kyiv, Ukraine
E-mail: koron@univ.kiev.ua

This paper reports on the investigation of the magneto-electric (ME) properties of domain walls and sub-structural magnetic nano-formations on domain walls in thin epitaxial films of ferrite garnets with using of the optical methods for investigation [1]. The investigated films were deposited on the (111) Gd3Ga5O12 substrate with a thickness of about 600 μm. The thickness of the films were about 7 μm. The domain's magnetization was near to normal to the film plane and the external electric field (ω = 800 Hz) was oriented perpendicular to the plane of the film.  We adapted the dark field optical microscopy method [2] to investigate the influence of an external electric field on the micromagnetic structural elements and inhomogeneities of the domain structure of thin magnetic films. We revealed the magneto-electric activity effect of vertical Bloch lines of investigated garnet films in external electric field which visually manifests itself as local distortion of their profile and broadening of the regions of their localization. This phenomena can be explained as the effect of additional amplification by the external electric field of the initially existing micro-slope of the domain wall region in the vicinity of the Bloch lines. These perturbations are significantly amplified in additional impact of the external magnetic field, oriented in the plane of the film along the domain walls profile. In particular, in the external AC electric field, we revealed visually observable displacement of the Bloch lines along the domain walls in the range of the DC magnetic field value approximately from 35 to 45 Oe. Reaction of the domain structure to influence of external AC electric field was caused by changing the magnetic anisotropy parameters of ferrite garnets in an external electric field.

1.	Koronovskyy V., Vakyla Y. Sensitivity of domain walls of bismuth-substituted iron garnets to a magneto-electric interactions caused by external complex field influence // JAP. - 2015. - 118. - P. 184101-1 - 184101-4.
2.	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.