PhysicaB319(2002)28–34 Structural and magnetic properties of Nd 2 Co 17x V x compounds B.D. Liu a,b ,Y.X.Li b ,W.X.Li a ,H.Y.Liu b ,G.H.Wu a , F.M. Yang a, *, F.R. de Boer c a State Key Laboratory of Magnetism, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, 100080 Beijing, China b School of Material Sciences and Engineering, Hebei University of Technology, Tianjin 300130, China c Van der Waals-Zeeman Instituut, Universiteit van Amsterdam, Valckenierstraat 65, 1018 XE Amsterdam, The Netherlands Received 17 January 2002; received in revised form 18 March 2002 Abstract TheeffectofsubstitutionofVforCoonthestructureandmagneticpropertiesofNd 2 Co 17x V x compounds(x ¼ 0; 0.5,1,1.5,2)hasbeeninvestigatedbymeansofXRDandmagneticmeasurements.Itisfoundthatallcompoundswith x from 0 to 2 are almost single phase with the Th 2 Zn 17 -type of structure. The lattice constants a; c and the unit-cell volume V show a tendency to increase with increasing V content. The Curie temperature decreases linearly with increasing V content at a rate of 240K per V atom substituted in Nd 2 Co 17 . A spin reorientation is observed in all compoundsinvestigatedandthespin-reorientationtemperature T sr changesfrom147Kfor x ¼ 0to474Kfor x ¼ 1:0 and is almost independent of the V content above x ¼ 1:0: The saturation magnetization M s of Nd 2 Co 17x V x compounds and the Co moment m Co in these compounds decreases monotonically with increasing V content. r 2002 Elsevier Science B.V. All rights reserved. PACS: 75.30.Gw Keywords: Nd 2 Co 17x V x compounds; Crystal structure; Spin reorientation 1. Introduction Recently, much attention has been devoted to the research on the rare-earth–cobalt compounds oftheR 2 Co 17 type (R stands for rare earth or Y) due to their high Curie temperature and high saturation magnetization as well as their potential application as high-temperature permanent mag- nets [1–3]. It is well known that all Co-based R 2 Co 17 compounds show planar anisotropy at roomtemperature,exceptforthecompoundswith R=Ce, Sm, Er and Tm [1]. However, Some Co- basedR 2 Co 17 compounds with planar anisotropy, like Gd 2 Co 17 , show a transition from planar anisotropy at room temperature to easy-axis anisotropy by substitution of Ga [4], Al [5], or Si [6] for Co. In the past years, Nd 2 Co 17 [1] and the Nd 2 Co 17x M x compoundswithM=Ga[7],Al[8] and Si [9] have been widely investigated. In order to investigate further the contribution of the *Correspondingauthor.Tel.:+86-010-8264-9250;fax:+86- 010-6256-2605. E-mail address: fmyang@aphy.iphy.ac.cn (F.M. Yang). 0921-4526/02/$-see front matter r 2002 Elsevier Science B.V. All rights reserved. PII:S0921-4526(02)01103-1