Crystal structure and properties of the new ternary YbZn x Ga 4x and Yb 3 Zn 11x Ga x phases Yu. Verbovytskyy * , L.C.J. Pereira, E.B. Lopes, A.P. Gonçalves Departamento de Química, Instituto Tecnológico e Nuclear/CFMC-UL, Estrada Nacional 10, P-2686-953 Sacavém Codex, Portugal article info Article history: Received 26 May 2011 Received in revised form 24 June 2011 Accepted 27 June 2011 Available online 23 July 2011 Keywords: A. Ternary alloy systems B. Crystal chemistry of intermetallics B. Electrical resistance B. Magnetic properties F. Diffraction (X-ray) abstract Crystal structures of three new ternary YbZn x Ga 4x (0.25  x  0.5 and 0.75  x  2) and Yb 3 Zn 11x Ga x (3.5  x  4.2) phases have been determined by means of single crystal X-ray as well as powder diffraction. They crystallize in known structure types, namely: CaCu 0.15 Ga 3.75 , BaAl 4 and La 3 Al 11 . Magnetic and transport properties were investigated for the new YbZn x Ga 4x compounds. All phases studied show metallic-like and diamagnetic behavior. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction Systematic studies of the ternary systems containing rare earth, transition and gallium metals have been extensively done during the last decades. Various compositions and structure types have been reported for this group compounds [1e3]. Among of them, ytterbium based intermetallic compounds are interesting from structural point of view, and due to their unusual physical prop- erties such as intermediate valence, anomalous magnetism, spin fluctuation, Kondo behavior and superconductivity [4]. Results on the identification of the new ternary compounds and construction of the isothermal section of the phase diagram for the Yb-Zn-Ga system has been already presented in our previous work [5]. One ternary compound YbZn x Ga 4x (x ¼ 3) with BaAl 4 type has been confirmed and three new compounds, YbZn x Ga 4x (x ¼ 0.25e0.5), Yb 3 Zn 11x Ga x (x ¼ 3.5e4.2) and YbZn 13x Ga x (x ¼ 1.8e2.7), have been found and their structure types were signed. Magnetic properties for the YbZn 0.251 Ga 3.753 (BaAl 4 -type) have been given by Grin in paper [6]. Authors suggested a non-magnetic groundstate of ytterbium atoms in above mentioned phase. In this work we present results of crystal structure determina- tion of the compounds from the YbGa 4 -“YbZn 4 ” cross-section and physical properties of the YbZn x Ga 4x phases. 2. Experimental details The samples were synthesized by directly melting the metals with nominal purities >99.95 wt% inside quartz ampoules under vacuum. The reactions were first performed at 900  C for 1 h. Fragments of the as-prepared ingots were sealed in evacuated quartz tubes and annealed at 400  C for 20 days. After the heat treatments, the samples were quenched by submerging the quartz tubes in cold water and analysed. The obtained products, with metallic-like lustres, were studied by X-ray powder and single crystal diffraction technique. A PANalytical X’Pert Pro diffractometer (Cu Ka-radiation) was used for the X-ray phase and structural analyses of the powdered polycrystalline samples. The scans were taken in the q/2q mode with the following parameters: 2q region, 15e120  ; step scan, 0.03  ; counting time per step, 20 s. The FullProf [7] program was used for single and multi phase Rietveld fittings. Data from single crystals were collected by using a four-circle Enraf-Nonius Mach III diffractometer with graphite mono- chromatized Mo Ka-radiation and a scintillation counter with pulse height discrimination. Scans were taken in the u/2q mode. Empi- rical absorption corrections were applied on the basis of J-scan data. The crystal structure was refined using Shelxl-97 [8] (full- matrix least-squares on F 2 ). The unit cell parameters were obtained by least-squares refinement of the 2q values of 25 intense and well- centered reflections from various parts of the reciprocal space (15  < 2q < 35  ). * Corresponding author. E-mail address: yuryvv@bigmir.net (Yu. Verbovytskyy). Contents lists available at ScienceDirect Intermetallics journal homepage: www.elsevier.com/locate/intermet 0966-9795/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.intermet.2011.06.019 Intermetallics 19 (2011) 1989e1995