Magnetic excitation localized near the interface between two ultrathin ferromagnets films Ouahiba Nafa a , Boualem Bourahla a,b, ⁎, Antoine Khater b a Laboratory of Physics and Quantum Chemistry, M. Mammeri University, BP17 RP, 15000 Tizi Ouzou, Algeria b Institute of Molecules and Materials du Mans UMR 6023, University du Maine, 72085 Le Mans, France abstract article info Article history: Received 24 September 2012 Received in revised form 5 June 2013 Accepted 7 June 2013 Available online 14 June 2013 Keywords: Localized spin states Magnon transmission Dynamic properties of thin films Magnetic interface This paper describes spinwaves localized states and the coherent magnon transport via magnetic interface between two different Heisenberg ultrathin ferromagnets films A/B and the inverse B/A. The model system consists of two semi-infinite ferromagnetically ordered slabs A and B, with different structures and the same thickness, joined together. The crystalline thin films A and B have, respectively, simple cubic and hex- agonal meshes. The transmission of magnons, scattering coherently at the interface boundary and localized spin states are calcu- lated and analyzed for the both films A/B and B/A. The theoretical calculations are carried out using the matching method. Transmission and reflection scattering cross sections are determined from elements of a Landauer type scattering matrix. The results highlight the localized spin states on the interface domain and their interactions with incident magnons. The results demonstrate also the magnetic properties of thin films at a microscopic scale. The calculated properties are presented for all accessible frequencies in the propagating bands, and for the interatomic magnetic exchange of the A and B films, and their spin intensity, with no externally applied mag- netic field. The magnons modes associated with interface domain, in layered structures, interact with propagat- ing modes of the perfect films, located on both sides, leading to interesting magnetic behaviors. Published by Elsevier B.V. 1. Introduction With the recent development of various experimental thin film growth techniques, numerous magnetic layered materials, e.g., single magnetic films [1], multilayered magnetic films [2] and superlattices [3], have become of great interest in condensed matter physics. The interest to these systems has been motivated by the particular impor- tance due to their rich magnetism physics and practical applications in magnetic recording industry [4,5]. During the past few years, thin magnetic films and multilayers constitute a topic of active investigations, both on the fundamental research level as well as on the applied one. Several works were car- ried out to understand the magnetic properties and the origin of the various interactions existing in this kind of systems [6]. The study of the above-mentioned systems has revealed particular phenomena [7,8] which are not observed in bulk solids of the same materials, and their magnetic properties are very different owing to the reduced dimensionality, which modifies their magnetic behavior with respect to those of the bulk. The investigation of spinwaves excitation in such a system is impor- tant, because the knowledge of their atomic scale structure and its consequence is hence required to understand their fundamental prop- erties, and to propose means of how to control their magnetic behavior for device applications. The film-film magnetic interface can hence strongly influence the spinwaves propagation, when these arise through the nanojunction zone [9]. With experimental techniques developing, many methods, such as Ferromagnetic Resonance [10] and Brillouin Light Scattering [11], have been used to explore spin waves. In addition, many authors have researched the spinwave excita- tions using a variety of theoretical methods, such as Green Function Method [12], Transfer-Matrix Method [13] and First Principle Method [14]. However, a direct numerical analysis by use of these methods leads to huge numerical computations. In this work, we present a model to study the spin excitations of a magnetic Heisenberg ultrathin film ferromagnets A/B and the inverse B/A. The model consists of two semi-infinite ferromagnetically ordered slabs A and B, with different structures and the same thickness, joined to- gether. The obtained film gives an interface between the semi-infinite slabs. The crystalline thin films A and B have simple cubic and hexagonal meshes, respectively. The localized spin states, coherent magnon trans- port via the magnetic interface are calculated and analyzed for the inter- face domain sites. The purpose is to give a microscopic theory of the properties of a spins, their dynamics at the interface band, and an under- standing of the relationship between the coherent magnon transmission via the interface zone, and the structural configuration of the latter. Thin Solid Films 540 (2013) 282–289 ⁎ Corresponding author at: Laboratory of Physics and Quantum Chemistry, M. Mammeri University, BP17 RP, 15000 Tizi Ouzou, Algeria. E-mail address: bourahla_boualem@yahoo.fr (B. Bourahla). 0040-6090/$ – see front matter. Published by Elsevier B.V. http://dx.doi.org/10.1016/j.tsf.2013.06.011 Contents lists available at SciVerse ScienceDirect Thin Solid Films journal homepage: www.elsevier.com/locate/tsf