Microelectronic Engineering 69 (2003) 330–335 www.elsevier.com / locate / mee Ion synthesis and FMR studies of iron and cobalt nanoparticles in polyimides a,b a a c a,b b B.Z. Rameev , F. Yıldız , B. Aktas ¸ , C. Okay , R.I. Khaibullin , E.P. Zheglov , d a,b,e, * J.C. Pivin , L.R. Tagirov a Gebze Institute of Technology, 41400 Gebze-Kocaeli, Turkey b Kazan Physical-Technical Institute, Sibirsky Trakt 10 /7, 420029 Kazan, Russia c ¨ Marmara University, 81040 Goztepe-Istanbul, Turkey d CSNSM, Batiment 108, IN2P3-CNRS, 91405 Orsay Campus, France e Kazan State University, Kremlevskaya str. 18, 420008 Kazan, Russia Abstract 1 1 17 2 Polyimide foils were implanted with 40 keV Fe and Co to doses of 0.25–1.5310 ions / cm . Electron microscopy studies showed the formation of iron and cobalt nanoparticles in the implanted polymer layer with a thickness of about 70 nm. The size and shape of the ion-synthesized metal nanoparticles depend on the implantation parameters and subsequent thermal annealing. A ferromagnetic resonance (FMR) response was found in the iron-implanted samples as well as in the annealed cobalt and iron samples. The effective magnetization values of the metal / polymer composite layers were extracted from the FMR spectra and plotted as a function of implantation dose. The magnetic properties of the iron and cobalt nanoparticles in polyimide are compared and discussed.  2003 Elsevier B.V. All rights reserved. Keywords: Ion implantation; Magnetic nanoparticles; Granular magnetic films; Ferromagnetic resonance PACS: 75.50.Tt; 75.70.-i; 76.30.Fc; 76.50.1g 1. Introduction tion storage, magneto-sensor electronics, magnetic resonance imaging enhancement, ferrofluids, mag- The synthesis and characterization of nanosize netic refrigeration, colour imaging, medical diagnos- magnetic particles are the subject of intense scientific tics, etc. [1]. research. This activity is inspired by the crossover Nanocrystalline cobalt and iron particles are phenomena related to quantum-size effects as well as among the most promising candidates for high-den- the important applications of nanostructured mag- sity recording media [2] and magnetic sensors based netic materials in magnetic recording and informa- on the giant tunnel-type magnetoresistance effect [3]. Dielectric matrices are usually used as the host for the nanocrystalline particles, to stabilize the metal granules against oxidization and prevent coalescence. Among the different techniques, ion implantation is a *Corresponding author. Kazan State University, Kremlevskaya very attractive and prospective preparation method str. 18, 420008 Kazan, Russia. Tel. / fax: 17-8432-381-573. E-mail address: lenar.tagirov@ksu.ru (L.R. Tagirov). because of its peculiar advantages, such as easy 0167-9317 / 03 / $ – see front matter  2003 Elsevier B.V. All rights reserved. doi:10.1016 / S0167-9317(03)00317-4