L Journal of Alloys and Compounds 316 (2001) 64–69 www.elsevier.com / locate / jallcom Crystal structure, magnetic and electrical properties of new ternary indides RPtIn (R5Pr, Sm) a a a b b b, * ´ V.I. Zaremba ,Y.V. Galadzhun , B.D. Belan , A. Pikul , J. Ste ¸pien-Damm , D. Kaczorowski a Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mephodiya Str. 6, 79005 Lviv, Ukraine b Polish Academy of Sciences, Institute of Low Temperatures and Structure Research, P .O. Box 1410, 50-950 Wrocl «aw, Poland Received 31 October 2000; accepted 13 November 2000 Abstract Two new ternary compounds PrPtIn and SmPtIn were synthesized and characterized by means of X-ray diffraction, magnetic and 2 electrical measurements. The crystal structure of SmPtIn was refined from single-crystal X-ray data, down to R 50.0406 for 297 F 1 values and 15 variables. The structure of PrPtIn was established from powder diffractometer data. Both compounds crystallize with a ¯ ˚ ˚ hexagonal structure of the ZrNiAl-type (space group P62 m) with the lattice parameters: a57.6522(3) A, c54.0455(1) A for PrPtIn, and ˚ ˚ a57.5895(6) A, c53.9540(1) A for SmPtIn. The Pr-based compound is paramagnetic down to 1.7 K, whereas SmPtIn orders ferromagnetically below 25 K. Both phases exhibit metallic character of the electrical conductivity.  2001 Elsevier Science B.V. All rights reserved. Keywords: Rare earth compounds; Transition metal compounds; Crystal structure; Electrical transport; Magnetic measurement 1. Introduction preliminary data on the magnetic and electrical behavior of both indides. The equiatomic compounds forming in the R–Pt–In ternary systems (R5Y, La, Ce, Nd, Gd, Dy, Er, Tm, Lu) were investigated for the first time by Ferro and co- workers [1,2]. All of them have been reported by these 2. Experimental details authors to crystallize with a hexagonal structure of the ZrNiAl-type [3], which is an ordered derivative of the Polycrystalline samples of PrPtIn and SmPtIn were Fe P-type [4]. More recently, the 1:1:1 phases with R5Yb prepared by arc melting stoichiometric amounts of con- 2 [5,6] and R5Sc, Tb, and Ho [7] were synthesized and also stituent elements (purities: Pr and Sm, 99.9%; Pt, 99.9% for these ternaries the ZrNiAl-type unit cells have been (Degussa); In, 99.999% (Johnson Matthey)) under argon found. Thus, to date the only compound from the RPtIn atmosphere. Argon was purified over titanium sponge. The series that exhibits different crystal structure is EuPtIn, for samples were turned over and remelted 2 times to ensure which an orthorhombic unit cell of the TiNiSi-type [8] has good homogeneity. The weight losses upon melting were been established [9]. smaller than 0.5%. Subsequently, parts of the melted In this paper we report on two hitherto unknown buttons were sealed in evacuated silica tubes and annealed ternaries, i.e. PrPtIn and SmPtIn, which complete the at 870 K for 1 month. whole series of RPtIn intermetallics. We show that, like all Powder X-ray diffraction patterns from annealed sam- the other phases but EuPtIn, the new compounds are ples were recorded on an automatic powder diffractometer isostructural to ZrNiAl. Moreover, we report here some DRON-3M with Cu Ka radiation, using silicon as an 1 internal standard. The diffractograms of both compounds resembled those characteristic of the ZrNiAl structure and were easily indexed within a hexagonal system. The *Corresponding author. Tel.: 148-71-343-5021; fax: 48-71-344-1029. E-mail address: dkaczor@int.pan.wroc.pl (D. Kaczorowski). measured intensities were in very good agreement with the 0925-8388 / 01 / $ – see front matter  2001 Elsevier Science B.V. All rights reserved. PII: S0925-8388(00)01455-9