L Journal of Alloys and Compounds 321 (2001) 27–34 www.elsevier.com / locate / jallcom Structure and magnetism of R Bi (R5Tb, Dy, Ho, Er) and Tb Bi 5 3 4 3 * M. Drzyzga , J. Szade Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland Received 29 November 2000; accepted 12 February 2001 Abstract The physical properties of the rare earth bismuthides R Bi (R5Tb, Dy, Ho, Er) and Tb Bi were investigated for the first time. The 5 3 4 3 R Bi compounds have been found to crystallise in the orthorhombic structure of the Y Bi -type whereas Tb Bi forms the cubic 5 3 5 3 4 3 anti-P Th structure. The temperature dependence of the DC and AC magnetic susceptibility and the electrical resistivity have been 4 3 measured. Tb Bi orders ferromagnetically at 190 K whereas R Bi show a complex form of magnetic ordering at lower temperatures. 4 3 5 3  2001 Elsevier Science B.V. All rights reserved. Keywords: Rare earth compounds; Crystal structure; Electronic transport; Magnetic measurements 1. Introduction 2. Experimental Compounds of rare earth with non-magnetic metals have The preparation of the samples was similar to the been intensively investigated over many years. However procedure described in our earlier paper on Gd-Bi com- only a few systematic studies of rare earth compounds with pounds. The high vapour pressure of Bi and the high bismuth have been performed so far. The single crystals of temperatures of compound formation make the sample Gd monopnictides, including GdBi, have been investigated preparation complicated. The polycrystalline samples of with many techniques including X-ray photoemission [1– R Bi (R5Tb, Dy, Ho, Er) and Tb Bi were obtained 5 3 4 3 3]. Our earlier paper reports on the magnetic properties and using induction melting in a two-step process. In the first electronic structure of polycrystalline Gd Bi and Gd Bi step the pieces of R (R5Tb, Dy, Ho, Er) (99.9%) and Bi 4 3 5 3 [4] indicating to the relations between these properties. (99.999%) were melted together using a levitation coil The existing phase diagrams for the systems of rare earth described elsewhere [8]. The starting weight of Bi was and bismuth show that compounds with the 4:3 stoi- taken to exceed the stoichiometric one by 10% to balance chiometry exist only for the light rare earths, Gd and Tb, the evaporated amount of this metal. Melting was per- whereas compounds of the 5:3 type are present in the formed in an argon atmosphere at an overpressure of about whole rare earth series [5,6]. Yoshihara et al. [7] described 400 mbar. The obtained porous mixture was then remelted two various crystal structures for the composition close to several times. During that process the weight loss was 7–8 R Bi where R is Gd, Tb, Dy, Ho and Er. No studies of wt.% and the final weight of a sample was close to the 5 3 the physical properties were described for this group of assumed one. Samples of R Bi (R5Tb, Dy, Ho, Er) were 5 3 compounds up to now. annealed for 1 week at 10008C, in vacuum. The weight In the present work we obtained the polycrystalline loss during the annealing was negligible. samples of Tb Bi and R Bi (for R5Tb, Dy, Ho and Er) The DC magnetic susceptibility measurements were 4 3 5 3 and studied their structure, magnetism and electrical performed using the Faraday method in the temperature resistivity. range 4.2–700 K, under an atmosphere of helium. The AC magnetic susceptibility was measured in the range 4.2–300 K, using a magnetic field with a frequency of 700 Hz and *Corresponding author. Tel.: 148-32-587-978; fax: 148-32-588-431. E-mail address: szade@us.edu.pl (M. Drzyzga). an amplitude of about 0.5 Oe. 0925-8388 / 01 / $ – see front matter  2001 Elsevier Science B.V. All rights reserved. PII: S0925-8388(01)01009-X