Crystal structure and magnetic properties of the ternary rare earth metal-rich transition metallides RE14T3Al3 (RE = Y, Gd–Tm, Lu; T = Co, Ni)

2019 ◽  
Vol 74 (1) ◽  
pp. 125-135 ◽  
Author(s):  
Frank Stegemann ◽  
Oliver Janka

AbstractThe rare earth metal-rich RE14T3Al3 series (RE=Y, Gd–Tm, Lu; T=Co, Ni) have been prepared by arc-melting the rare earth metals with appropriate amounts of TAl precursors. All compounds crystallize in the tetragonal crystal system with space group P42/nmc in the Gd14Co3In2.7-type structure. Two structures (Y14Co2.78(1)Al3.22(1): a=952.99(4), c=2292.98(10) pm, wR2=0.0423, 2225 F2 values, 63 variables; Y14Ni3.07(2)Al2.93(2): a=955.06(5), c=2298.77(10) pm, wR2=0.0416, 2225 F2 values, 63 variables) have been refined from single-crystal data, indicating T/Al mixing on one crystallographic site. The lattice parameters of all members have been refined from powder X-ray diffraction experiments. The Y and Lu containing compounds for T=Co and Ni exhibit Pauli paramagnetic behavior, indicating that the Co and Ni atoms exhibit no localized magnetic moment in line with a filled 3d band. The other compounds show paramagnetism, in line with the rare earth atoms in the trivalent oxidation state. Detailed magnetic investigations, however, were impossible due to the presence of e.g. RE3T trace impurities.

2018 ◽  
Vol 73 (11) ◽  
pp. 927-942 ◽  
Author(s):  
Frank Stegemann ◽  
Oliver Janka

AbstractThe rare earth metal-rich cobalt and nickel aluminium compounds with the general compositions RE6Co2Al (RE=Sc, Y, Nd, Sm, Gd–Tm, Lu) and RE6Ni2.25Al0.75 (RE=Y, Gd–Tm, Lu) have been synthesised from the elements by arc-melting, followed by annealing. Single-crystal X-ray diffraction experiments on Y6Co2.02(1)Al0.98(1) (Ho6Co2Ga type; Immm; a=944.1(2), b=952.4(2), c=999.0(2) pm; wR2=0.0452, 1123 F2 values, 35 variables) and Y6Ni2.26(1)Al0.74(1) (Ho6Co2Ga type; Immm; a=938.30(5), b=959.45(5), c=996.05(6) pm; wR2=0.0499, 1131 F2 values, 35 variables) revealed that the compounds form solid solutions according to the general formula RE6(Co/Ni)2+xAl1−x with different homogeneity ranges. The compounds of the Ni series can be obtained in X-ray pure form only with the nominal composition RE6Ni2.25Al0.75. A significant increase of the U22 component of the anisotropic displacement parameters of the Co/Ni2 atoms (4g site) was observed that requires a description of the structure with a split-position model at RT. Further investigations by low temperature (90 K) single-crystal X-ray diffraction experiments of Y6Co2.02(1)Al0.98(1) showed a significant decrease of U22. Magnetic measurements were conducted on the X-ray pure members of the RE6Co2Al (RE=Y, Dy–Tm, Lu) series. Antiferromagnetic ordering was observed for the members with unpaired f electrons with Néel temperatures up to TN=48.0(1) K and two spin reorientations for Dy6Co2Al.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Michael Zoller ◽  
Hubert Huppertz

AbstractThe rare earth oxoborates REB5O8(OH)2 (RE = Ho, Er, Tm) were synthesized in a Walker-type multianvil apparatus at a pressure of 2.5 GPa and a temperature of 673 K. Single-crystal X-ray diffraction data provided the basis for the structure solution and refinement. The compounds crystallize in the monoclinic space group C2 (no. 5) and are composed of a layer-like structure containing dreier and sechser rings of corner sharing [BO4]5− tetrahedra. The rare earth metal cations are coordinated between two adjacent sechser rings. Further characterization was performed utilizing IR spectroscopy.


1989 ◽  
Vol 151 ◽  
Author(s):  
W. R. Bennett ◽  
R. F. C. Farrow ◽  
S. S. P. Parkin ◽  
E. E. Marinero

ABSTRACTWe report on the new epitaxial system LaF3/Er/Dy/Er/LaF3/GaAs (111) grown by molecular beam epitaxy. X-ray diffraction studies have been used to determine the epitaxial relationships between the rare earths, the LaF3 and the substrate. Further studies of symmetric and asymmetric reflections yielded the in-plane and perpendicular strain components of the rare earth layers. Such systems may be used to probe the effects of magnetoelastic interactions and dimensionality on magnetic ordering in rare earth metal films and multilayers.


2013 ◽  
Vol 68 (5-6) ◽  
pp. 625-634 ◽  
Author(s):  
Bastian Reker ◽  
Samir F. Matar ◽  
Ute Ch. Rodewald ◽  
Rolf-Dieter Hoffmann ◽  
Rainer Pöttgen

Small single crystals of the Sm5Ge4-type (space group Pnma) germanides RE2Nb3Ge4 (RE = Sc, Y, Gd-Er, Lu) and Sc2Ta3Ge4 were synthesized by arc-melting of the respective elements. The samples were characterized by powder and single-crystal X-ray diffraction. In all structures, except for Sc2.04Nb2.96Ge4 and Sc2.19Ta2.81Ge4, the rare earth and niobium atoms show full ordering on the three crystallographically independent samarium sites of the Sm5Ge4 type. Two sites with coordination number 6 are occupied by niobium, while the slightly larger site with coordination number 7 is filled with the rare earth element. Small homogeneity ranges with RE=Nb and RE=Ta mixing can be expected for all compounds. The ordered substitution of two rare earth sites by niobium or tantalum has drastic effects on the coordination number and chemical bonding. This was studied for the pair Y5Ge4/Y2Nb3Ge4. Electronic structure calculations show larger charge transfer from yttrium to germanium for Y5Ge4, contrary to Y2Nb3Ge4 which shows stronger covalent bonding due to the presence of Nb replacing Y at two sites


ChemInform ◽  
2016 ◽  
Vol 47 (45) ◽  
Author(s):  
Danuta Dutczak ◽  
Markus Stroebele ◽  
David Enseling ◽  
Thomas Juestel ◽  
H.-Juergen Meyer

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