Preparation and magnetoresistance behavior of nickel nanoparticles embedded in hydrogenated carbon film Mehrdad Molamohammadi 1 • Carlos Luna 2 • Ali Arman 1 • Shahram Solaymani 1 • Arash Boochani 3 • Azin Ahmadpourian 3 • Azizollah Shafiekhani 4,5 Received: 30 April 2015 / Accepted: 30 May 2015 / Published online: 12 June 2015 Ó Springer Science+Business Media New York 2015 Abstract Nickel nanoparticles arrays, growth into hydro- genated amorphous carbon, were prepared by means of RF- plasma enhanced chemical vapor deposition and RF-sput- tering co-deposition from acetylene and a nickel target. The resulting nanocomposite films were characterized by X-ray diffraction and atomic force microscopy, and their magnetic responses and magnetoresistance behavior were investigated as a function of the exciting magnetic field and the Ni nanoparticles content, which was conveniently controlled by adjusting the deposition time. These physical properties were explained by a combination of hopping and tunneling effects. 1 Introduction Nanostructure materials are crucial elements for the advance of several scientific disciplines and the develop- ment of innovative devices [1]. The interest of these systems is largely due to their size-dependent physico- chemical properties that can be rather different than those observed in their bulk analogous, and which can be uniquely tailored for various types of applications by properly selecting their composition, structure, size and morphology and the particle arrangement. In this regards, arrays of fine magnetic nanoparticles are of huge current importance due to the understanding of their magnetic phenomenology is essential for the progress of the physics of magnetism and the advance of revolutionary technolo- gies such as ultrahigh-density magnetic recording media [2], nanomedicine [3–5] and spintronics [6]. Nowadays, given the development of more and more advanced preparation techniques, there is a large variety of methods based on top-down and bottom-up approaches that allow the preparation of two-dimensional arrays of mag- netic nanoparticles with different morphologies, composi- tions and structures [2, 7–11]. In this matter, the sputtering [12, 13] and the chemical vapor deposition techniques [14] have been especially relevant, and their versatility have recently combined to prepare nanocomposite films [15– 20]. In this article we study the magnetic response and the magnetoresistance behavior at room temperature of nanocomposite films constituted by fine nickel nanopar- ticles embedded into hydrogenated amorphous carbon prepared by a combination of plasma enhanced chemical vapor deposition (RF-PECVD) and RF-sputtering. The morphology and the crystal structure were analyzed by atomic force microscopy (AFM) and X-ray diffraction (XRD), respectively, and the effects of the Ni concen- tration nanoparticles and the applied magnetic field on magnetization and transport measurements have been investigated. & Ali Arman ali.arman173@gmail.com; Ali.gelali@gmail.com 1 Young Researchers and Elite Club, Kermanshah Branch, Islamic Azad University, Kermanshah, Iran 2 Facultad de Ciencias Fı ´sico Matema ´ticas, Universidad Auto ´noma de Nuevo Leo ´n, Av. Pedro de Alba s/n, 66455 San Nicola ´s de los Garza, Nuevo Leo ´n, Mexico 3 Department of Physics, Kermanshah Branch, Islamic Azad University, Kermanshah, Iran 4 School of Physics, Institute for Research in Fundamental Sciences, P.O. Box 19395-5531, Tehran, Iran 5 Physics Department, Alzahra University, 1993893973 Tehran, Iran 123 J Mater Sci: Mater Electron (2015) 26:6814–6818 DOI 10.1007/s10854-015-3294-7