Journal of Magnetism and Magnetic Materials 272–276 (2004) e1881–e1882 Magnetic properties and microstructures of the aerosol-deposited permanent magnet films Satoshi Sugimoto a, *, Jun Akedo b , Maxim Lebedev b , Koichiro Inomata a a Department of Materials Science, Graduate School of Engineering, Tohoku University, Aoba-yama 02, Sendai 980-8579, Japan b National Institute of Advanced Industrial Science and Technology (AIST), 1-2 Namiki, Tsukuba, Ibaraki 305-8564, Japan Abstract This paper describes magnetic properties and microstructures of Sm–Fe–N films prepared by the aerosol deposition (AD) method. Microstructural observations revealed that the films consisted of small Sm 2 Fe 17 N x grains with diameter of 200–400 nm. The Sm–Fe–N films showed the saturation magnetization (J s ) of 0.613–0.755T, remanence (J r ) of 0.395–0.557T and coercivity (m 0 H cJ ) of 1.624–1.816T, respectively. r 2003 Elsevier B.V. All rights reserved. PACS: 75.50.Ww; 75.50.Vv Keywords: Aerosol deposition method; Coercivity; High deposition rate; Sm–Fe–N film 1. Introduction Rare-earth magnets with thicknesses less than 300-mm can reduce the size of motors and accelerate the development of electro-mobile devices. Sputtering [1,2] and plasma laser deposition (PLD) [3,4] methods have been applied in preparing rare-earth film magnets. However, their deposition rate has not been sufficient for manufacturing film magnets for the use in electro- mobile devices. The aerosol deposition (AD) method reported as one of the fabrication processes for fine ceramics films such as PZT and Al 2 O 3 , is expected to achieve a high deposition rate and high film density [5]. In our previous paper [6], the possibility of the AD method for the fabrication of Sm–Fe–N thick film magnets was investigated and the films with high coercivities around 1.8T were obtained with high deposition rates of 2–10 mm/min. However, the relation- ship between their magnetic properties and microstruc- ture was not clear. Therefore, the purpose of this study is to investigate the relationship. 2. Experimental procedure The Sm 2 Fe 17 N x powders (average particle size: 3 mm, Sumitomo Metal Mining Co. Ltd.) were used for the AD method. The principle of the AD method is the shock loading densification of ultra fine particles to substrates, of which details were described in our previous paper [6]. The Sm 2 Fe 17 N x fine powders formed an aerosol flow by mixing with a carrier gas (He) in the aerosol chamber. The aerosol flow was ejected from the nozzle into the deposition chamber, which was evacuated by a rotary pump. To control the fine powders velocity, the gas consumption (gas flow rate: gfr) was varied from 1 to 10 l/min. The substrates (SiO 2 ) were placed at a distance of 1–25mm from the nozzle, and were maintained at room temperature. The magnetic properties were measured by a VSM after applying a pulsed field around 4T. The magnetiza- tion values were calculated using film weight and the X-ray density of the Sm 2 Fe 17 N 3 compound (7.67Mg/m 3 ) reported. The microstructures were ARTICLE IN PRESS *Corresponding author. Tel.: +81-22-217-7332; fax: +81- 22-217-7332. E-mail address: sugimots@material.tohoku.ac.jp (S. Sugimoto). 0304-8853/$-see front matter r 2003 Elsevier B.V. All rights reserved. doi:10.1016/j.jmmm.2003.12.607