Homogeneity ranges and physical properties of ternary Laves phases RxZr1-xNi2 (R = Gd-Lu)

Homogeneity ranges and lattice parameters of the ternary compounds RxZr1-xNi2 (R = Gd-Lu) with cubic MgCu2-type structure have been refined from powder XRD and EDXS data: 0.22 <= x <= 0.27 for Gd, 0.12 <= x <= 0.27 for Tb and Ho, 0.12 <= x <= 0.24 for Dy, Er, and Tm, 0.22 <= x <= 0.24 for Yb and 0.23 <= x <= 0.24 for Lu at 870 K. The crystal structure has been also investigated for two single crystals Dy0.16Zr0.84Ni2 and Tm0.17Zr0.83Ni2 from the XRD data: MgCu2 type structure, space group Fd (3) over barm, Z = 8, a = 6.988(5)angstrom, R1 = 0.055 for 54 independent reflections I-o > 2s(I-o)) for Dy0.16Zr0.84Ni2 and a = 6.976(5) angstrom, R1 = 0.053 for 46 independent reflections I-o > 2 sigma(I-o) for Tm0.17Zr0.83Ni2. The electronic structure of RxZr1-xNi2 was studied with the TB-LMTO method. Y0.22Zr0.78Ni2 and Lu0.23Zr0.77Ni2 are temperature independent Pauli paramagnets and exhibit for T < 6 K a simple normal metal behavior with a Debye temperature Theta(D) near 370 K RxZr1-xNi2 (R = Dy to Tm) reveal a Curie-Weiss paramagnetic behavior down to 3 K with effective magnetic moments approximately corresponding to the value of R3+ ions. (C) 2015 Elsevier B.V. All rights reserved.