L Journal of Alloys and Compounds 322 (2001) 37–41 www.elsevier.com / locate / jallcom Magnetic properties of Sm Fe crystal 6 23 a b c ,1 c ,1 c c, * H. Samata , T. Uchida , Y. Shimizu , S. Sato , S.M. Yashiro , Y. Nagata a Faculty of Mercantile Marine Science, Kobe University of Mercantile Marine, Fukaeminami, Higashinada, Kobe 658-0022, Japan b Faculty of Engineering, Tokyo Institute of Polytechnics, Iiyama, Atsugi, Kanagawa 243-0297, Japan c College of Science and Engineering, Aoyama Gakuin University, Chitosedai, Setagaya, Tokyo 157-8572, Japan Received 7 February 2001; accepted 20 February 2001 Abstract A single crystal of Sm Fe was prepared by means of a modified self-flux method, and its crystallographic magnetic properties were 6 23 studied. Sm Fe has the cubic Th Mn -type structure (space group Fm3m) with a lattice constant of a 5 1.218760.0006 nm. The easy 6 23 6 23 axis of magnetization is parallel to the k111l direction. Its magnetic moment per unit formula deduced from the saturation magnetization is 59 m at 5 K, a value that is consistent with the value calculated assuming ferromagnetic coupling between the Sm and Fe sublattices. The B 6 cubic anisotropy constants K and K estimated from the magnetization curves of the [111], [110], and [100] directions are 22.7310 1 2 5 3 and 6.3 310 erg / cm , respectively. The anisotropy field H calculated from the anisotropy constants is 6.1 kOe.  2001 Elsevier A Science B.V. All rights reserved. Keywords: Rare earth compounds; Transition metal compounds; Anisotropy; Magnetic measurements 1. Introduction these compounds, a precise study on a single-crystal specimen is essential. However, crystal growth has not Since the report of a notable improvement in the hard been successful for the compounds in the Sm–Fe system magnetic properties for a nitrogenated compound because of the incongruent melting of these compounds. Sm Fe N [1], which has a theoretical maximum energy Recently, a new crystal growth technique for the com- 2 17 x product of 62 MGOe [2] comparable to that of the Nd–Fe– pounds in the Sm–Fe system was developed using a flux B hard magnet, the Sm–Fe system has attracted much method, and the magnetism of SmFe , SmFe , and SmFe 2 3 7 attention as a source of practical magnetic materials. The was studied in detail using single-crystal specimens Sm–Fe system appears to be promising in the search for [7,9,12–14]. In particular, the discovery of a SmFe phase 7 new high-performance magnetic materials. In the Sm–Fe with excellent hard magnetic properties has given consid- system, the existence of several magnetic phases, such as erable impulse to studies on hard magnetic materials. SmFe , SmFe , Sm Fe , SmFe , and Sm Fe , has been In spite of extensive studies on the compounds in the 2 3 6 23 7 2 17 reported [3–10]. The compounds possess cubic, hexagonal, Sm–Fe system, the magnetism of Sm Fe has not yet 6 23 or tetragonal structure and show ferrimagnetism or ferro- been ascertained because of the lack of a single-crystal magnetism depending on the composition ratio of the rare specimen. Sm Fe is of great interest among the com- 6 23 earth and iron. Although many studies have been per- pounds in the Sm–Fe system because it contains large formed for these compounds using polycrystalline speci- amounts of iron in the unit cell. The magnetic properties of mens, almost all have focused on SmFe and Sm Fe Sm Fe were studied, for the first time, in the system 2 2 17 6 23 [1,3,4,10,11], and studies on other compounds are lacking. Sm Mn Fe using polycrystalline specimens, and it was 6 232x x In order to understand the intrinsic magnetic properties of reported that Sm Fe has a cubic Th Mn -type structure 6 23 6 23 of space group Fm3 m and shows ferrimagnetism with a Curie temperature of 390 K [8]. However, there have been *Corresponding author. few studies on Sm Fe since then. This seems to be due 6 23 E-mail address: ynag@ee.aoyama.ac.jp (Y. Nagata). 1 to the difficulty entailed in preparing a specimen of the Present address: Sony Corporation, Kitashinagawa, Shinagawa, Tokyo 141, Japan. Sm Fe phase. In order to characterize the magnetic 6 23 0925-8388 / 01 / $ – see front matter  2001 Elsevier Science B.V. All rights reserved. PII: S0925-8388(01)01174-4