Influence of implantation on the optical and magneto-optical properties of garnet surface Lali Kalandadze n Department of Physics, Batumi State University, Batumi 6010, Georgia article info Keywords: Implanted garnet films Equatorial Kerr effect Soft magnetic films abstract We have investigated the optical and magneto-optical properties of the ion-implanted (YBiCa) 3 (FeGe) 5 O 12 garnet films. It has shown that ion implantation influences significantly the magneto- optical properties of the garnet films and practically does not change its optical characteristics. The research of magnetization processes of implanted films showed that implantation leads to a significant inhibition of the growth of anisotropy. The latter is expressed in the decrease of the amount of saturation fields in-plane films. In the proceeding, we have researched the magneto-optical properties of ion- implanted (YBiCa) 3 (FeGe) 5 O 12 garnet films after it was annealed at 270 1C. We have also determined the spectral dependences of the component of the tensor of dielectric permittivity for the surface of the ferrite–garnet films before and after implantation process. These calculations let us evaluate the influence of implantation on an electronic energy structure of the surface layer for the sample. & 2014 Elsevier B.V. All rights reserved. 1. Introduction Nowadays it has been a particular interest to study the magneto-optical properties of ultrafine magnetic structures. Magneto-optical investigation of these types of structures such as: magnetic fluids, thin discontinuous metal films, heterogenic glasses etc are the subject of overall interest conditioned by both theoretical and practical significance. Besides, the ultrafine mag- netic structures with structural heterogeneities, there are the media, heterogeneities of which carry magnetic character [1,2]. Heterogeneous magnetic structures could be formed in the surface layer of the solid by the different kind of outer impact, for instance, by the ion implantation. Implantation affects the physi- cal–chemical properties, phase composition and surface structure of the solid. As a result, different radiation defects may cause the heterogeneity of the local magnetic properties. There are considerable scientific and practical interests regard- ing investigation of the characteristic properties of magneto- optical behavior of the ion-implanted garnet films [1,2]. In the present work we give the results of magneto-optical and optical investigations of the properties of the surface regions of the ion-implanted (YBiCa) 3 (FeGe) 5 O 12 garnet films. The magneto-optical method of investigation of the surface of the solid [3], in which use is made of the fact that the light reflected from a magnetized medium penetrates into a sample to a small depth and the magneto-optical reflection effects are propor- tional to the magnetization of the surface layer, has already been widespread. This investigative method lets us take over changes in the structure of an elementary cell of the solid, examine superficial magnetic transformation and discover heterogeneous magnetic structures. 2. Experimental details In our experiments we used (YBiCa) 3 (FeGe) 5 O 12 garnet films of 1.0 μm thickness prepared by means of liquid phase epitaxy on Gd 3 Ga 5 O 12 substrates with the (1 1 1) crystallographic orientation. The thickness of the substrates was 450 μm. The implantation process was carried out at the room tem- perature by Ne þ ions with energy of 100 keV and with various doses (0.5–2.5)  10 14 ion/cm 2 . During this process, permeation depth of the implanted ions covered 0.1 μm, maximum quantity of the implanted ions went to the depth 0.07 μm. For the magneto-optical investigation of a garnet surface we have chosen the odd-magnetization equatorial Kerr effect (EKE). The EKE consists in a change in the intensity of linearly polarized light reflected from the sample in the case of reversal of magne- tization of the sample. It can be written as δ ¼ I H  I H ¼ 0 I H ¼ 0 ð1Þ Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/jmmm Journal of Magnetism and Magnetic Materials http://dx.doi.org/10.1016/j.jmmm.2014.02.036 0304-8853 & 2014 Elsevier B.V. All rights reserved. n Tel.: þ995 59 330 0666. E-mail address: Lali62@mail.ru Please cite this article as: L. Kalandadze, Journal of Magnetism and Magnetic Materials (2014), http://dx.doi.org/10.1016/j. jmmm.2014.02.036i Journal of Magnetism and Magnetic Materials ∎ (∎∎∎∎) ∎∎∎–∎∎∎