STRUCTURAL AND MAGNETIC PROPERTIES OF SINGLE CRYSTAL RARE EARTH Gd-Y SUPERLATTICES

1985 ◽  
Vol 56 ◽  
Author(s):  
J. Kwo ◽  
D. B. McWhan ◽  
M. Hong ◽  
E. M. Gyorgy ◽  
F. J. DiSalvo
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Magnetic Ordering ◽  
X Ray Diffraction ◽  
Simple Diffusion ◽  
X Ray ◽  
Composition Modulation ◽  
Strain Modulation ◽  
Simple Diffusion Model ◽  
Magnetization Behavior

AbstractHigh quality single crystal rare earth Gd-Y superlattices with wavelength varying from 8to 42 atomic layers were grown by the recently developed metal molecular beam epitaxy technique. The crystallinity and coherence of the superlattices were examined by X-ray diffraction, and the profiles of composition modulation and strain modulation were determined from a quantitative analysis based on a simple diffusion model for the Gd-Y interfaces. The sharp boundaries achieved in these metallic superlattices are approaching those in semiconductor superlattices. The various in-plane magnetization behavior at low fieldsamong superlattices of different wavelengths suggests the possible presence of new magnetic ordering structures as caused by the artificial modulation.

X-Ray Diffraction Study of Rare Earth Epitaxial Structures Grown by MBE onto (111) GaAs

1989 ◽  
Vol 151 ◽  
Author(s):  
W. R. Bennett ◽  
R. F. C. Farrow ◽  
S. S. P. Parkin ◽  
E. E. Marinero
Keyword(s):  
Rare Earth ◽  
Molecular Beam Epitaxy ◽  
Rare Earth Metal ◽  
Molecular Beam ◽  
Earth Metal ◽  
Magnetic Ordering ◽  
Metal Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Strain Components

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.

scholarly journals Intermetallic REPtZn Compounds with TiNiSi-type Structure

2011 ◽  
Vol 66 (7) ◽  
pp. 671-676 ◽  
Author(s):  
Trinath Mishra ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Coordination Number ◽  
High Frequency ◽  
Three Dimensional ◽  
Type Structure ◽  
Rare Earth Compounds ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
X Ray

The equiatomic rare earth compounds REPtZn (RE = Y, Pr, Nd, Gd-Tm) were synthesized from the elements in sealed tantalum tubes by high-frequency melting at 1500 K followed by annealing at 1120 K and quenching. The samples were characterized by powder X-ray diffraction. The structures of four crystals were refined from single-crystal diffractometer data: TiNiSi type, Pnma, a = 707.1(1), b = 430.0(1), c = 812.4(1) pm, wR2 = 0.066, 602 F2, 21 variables for PrPt1.056Zn0.944; a = 695.2(1), b = 419.9(1), c = 804.8(1) pm, wR2 = 0.041, 522 F2, 21 variables for GdPt0.941Zn1.059; a = 688.2(1), b = 408.1(1), c = 812.5(1) pm, wR2 = 0.041, 497 F2, 22 variables for HoPt1.055Zn0.945; a = 686.9(1), b = 407.8(1), c = 810.4(1) pm, wR2 = 0.061, 779 F2, 20 variables for ErPtZn. The single-crystal data indicate small homogeneity ranges REPt1±xZn1±x. The platinum and zinc atoms build up three-dimensional [PtZn] networks (265 - 269 pm Pt-Zn in ErPtZn) in which the erbium atoms fill cages with coordination number 16 (6 Pt + 6 Zn + 4 Er). Bonding of the erbium atoms to the [PtZn] network proceeds via shorter RE-Pt distances, i. e. 288 - 293 pm in ErPtZn.

Single-crystal Data of Ternary Germanides RE2Nb3Ge4 (RE = Sc, Y, Gd–Er, Lu) and Sc2Ta3Ge4 with Ordered Sm5Ge4-type Structure

2013 ◽  
Vol 68 (5-6) ◽  
pp. 625-634 ◽  
Author(s):  
Bastian Reker ◽  
Samir F. Matar ◽  
Ute Ch. Rodewald ◽  
Rolf-Dieter Hoffmann ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Coordination Number ◽  
Electronic Structure Calculations ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Arc Melting ◽  
Structure Calculations ◽  
The Rare Earth

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

Structural analysis of Gd6FeBi2 from single-crystal X-ray diffraction methods and electronic structure calculations

2019 ◽  
Vol 75 (5) ◽  
pp. 562-567 ◽  
Author(s):  
Jiliang Zhang ◽  
Yong-Mook Kang ◽  
Guangcun Shan ◽  
Svilen Bobev
Keyword(s):  
Electronic Structure ◽  
Single Crystal ◽  
First Principles ◽  
Earth Metal ◽  
Magnetic Ordering ◽  
Additional Contribution ◽  
First Principles Calculations ◽  
X Ray Diffraction ◽  
Magnetic Exchange ◽  
X Ray

The crystal structure of the gadolinium iron bismuthide Gd6FeBi2 has been characterized by single-crystal X-ray diffraction data and analyzed in detail using first-principles calculations. The structure is isotypic with the Zr6CoAl2 structure, which is a variant of the ZrNiAl structure and its binary prototype Fe2P (Pearson code hP9, Wyckoff sequence g f d a). As such, the structure is best viewed as an array of tricapped trigonal prisms of Gd atoms centered alternately by Fe and Bi. The magnetic-ordering temperature of this compound (ca 350 K) is much higher than that of other rare-earth metal-rich phases with the same or related structures. It is also higher than the ordering temperature of many other Gd-rich ternary phases, where the magnetic exchange is typically governed by Ruderman–Kittel–Kasuya–Yosida (RKKY) interactions. First-principles calculations reveal a larger than expected Gd magnetic moment, with the additional contribution arising from the Gd 5d electrons. The electronic structure analysis suggests strong Gd 5d–Fe 3d hybridization to be the cause of this effect, rather than weak interactions between Gd and Bi. These details are of importance for understanding the magnetic response and explaining the high ordering temperature in this material.

scholarly journals Redetermination of the crystal structures of rare-earth trirhodium diboride RERh3B2 (RE = Pr, Nd and Sm) from single-crystal X-ray data

2022 ◽  
Vol 78 (1) ◽  
Author(s):  
Makoto Tokuda ◽  
Kunio Yubuta ◽  
Toetsu Shishido ◽  
Kazumasa Sugiyama
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Crystal Structures ◽  
Site Symmetry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Type Layer ◽  
Wyckoff Position ◽  
Powder Samples ◽  
Anisotropic Displacement Parameters

The crystal structures of the rare-earth (RE) trirhodium diborides praseodymium trirhodium diboride, PrRh3B2, neodymium trirhodium diboride, NdRh3B2, and samarium trirhodium diboride, SmRh3B2, were refined on the basis of single-crystal X-ray diffraction data. The crystal chemistry of RERh3B2 (RE: Pr, Nd, and Sm) compounds has previously been analyzed mainly on the basis of powder samples [Ku et al. (1980). Solid State Commun. 35, 91–96], and no structural investigation by single-crystal X-ray diffraction has been reported so far. The crystal structures of the three hexagonal RERh3B2 compounds are isotypic with that of CeRh3B2; RE, Rh and B sites are situated on special positions with site symmetry 6/mmm (Wyckoff position 1a), mmm (3g) and \overline{6}m2 (2c), respectively. In comparison with the previous powder X-ray study of hexagonal RERh3B2, the present redetermination against single-crystal X-ray data has allowed for the modeling of all atoms with anisotropic displacement parameters (ADPs). The ADPs of the Rh atom in each of the structures result in an elongated displacement ellipsoid in the direction of the stacking of the Rh kagomé-type layer. The features of obtained ADPs of atoms are discussed in relation to RERh3B2-type and analogous structures.

scholarly journals Remodelling a Shp: Transmetallation in a Rare-Earth Cluster-Based Metal–Organic Framework

2021 ◽  
Author(s):  
Hudson de Aguiar Bicalho ◽  
P. Rafael Donnarumma ◽  
Victor Quezada-Novoa ◽  
Hatem M. Titi ◽  
Ashlee J Howarth
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Surface Area ◽  
De Novo ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Metal Exchange ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metal Organic

<div> <p>Post-synthetic modification (PSM) of metal–organic frameworks (MOFs) is an important strategy for accessing MOF analogues that cannot be easily synthesized <i>de novo</i>. In this work, the rare-earth (RE) cluster-based MOF, Y-CU-10, with <b>shp</b> topology was modified through transmetallation using a series of RE ions, including: La(III), Nd(III), Eu(III), Tb(III), Er(III), Tm(III), and Yb(III). In all cases, metal-exchange higher than 70 % was observed, with reproducible results. All transmetallated materials were fully characterized and compared to the parent MOF, Y-CU-10, in regards to crystallinity, surface area, and morphology. Additionally, single-crystal X-ray diffraction (SCXRD) measurements were performed to provide further evidence of transmetallation occurring in the nonanuclear cluster nodes of the MOF. </p> </div>

Two series of rare earth metal-rich ternary aluminium transition metallides – RE6Co2Al (RE=Sc, Y, Nd, Sm, Gd–Tm, Lu) and RE6Ni2.25Al0.75 (RE=Y, Gd–Tm, Lu)

2018 ◽  
Vol 73 (11) ◽  
pp. 927-942 ◽  
Author(s):  
Frank Stegemann ◽  
Oliver Janka
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Rare Earth Metal ◽  
Magnetic Measurements ◽  
Earth Metal ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Antiferromagnetic Ordering ◽  
Arc Melting

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.

On the Crystal Structure and Optical Spectroscopy of Rare Earth Comprising Quaternary Tungstates Li3Ba2RE3(WO4)8 (RE = La-Nd, Sm-Ho)

2021 ◽  
Author(s):  
Jan-Niklas Keil ◽  
Christian Paulsen ◽  
Florian Rosner ◽  
Rainer Pöttgen ◽  
Thomas Jüstel
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Single Crystal ◽  
Optical Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthesis Route ◽  
Ceramic Synthesis

The quaternary tungstates Li3Ba2RE3(WO4)8 (RE = La-Nd, Sm-Ho) were obtained by a ceramic synthesis route and were characterized by powder and single crystal X-ray diffraction. The structures of Li3Ba2Pr3(WO4)8 and Li3Ba2Tb3(WO4)8 were...

RE2B8O15 (RE = La, Pr, Nd) – syntheses of three new rare earth borates isotypic to Ce2B8O15

2016 ◽  
Vol 71 (5) ◽  
pp. 535-542 ◽  
Author(s):  
Matthias Glätzle ◽  
Gregor J. Hoerder ◽  
Hubert Huppertz
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Single Crystal ◽  
Infrared Spectra ◽  
Diffraction Data ◽  
Boron Oxide ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
New Compounds

AbstractThe rare earth borates RE2B8O15 (RE = La, Pr, Nd) were synthesized in a Walker-type multianvil apparatus under conditions of 5.5 GPa and 1100 °C. Starting from the corresponding rare earth oxides and boron oxide, the syntheses yielded crystalline products of all new compounds that allowed crystal structure analyses based on single-crystal X-ray diffraction data for La2B8O15 and Nd2B8O15. The compound Pr2B8O15 could be characterized via X-ray powder diffractometry. The results show that the new compounds crystallize isotypically to Ce2B8O15 in the monoclinic space group P2/c. The infrared spectra of RE2B8O15 (RE = La, Pr, Nd) have also been studied.

scholarly journals Zr-Rich Eudialyte from the Lovozero Peralkaline Massif, Kola Peninsula, Russia

Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 982
Author(s):  
Taras L. Panikorovskii ◽  
Julia A. Mikhailova ◽  
Yakov A. Pakhomovsky ◽  
Ayya V. Bazai ◽  
Sergey M. Aksenov ◽  
...  
Keyword(s):  
Rare Earth ◽  
Chemical Composition ◽  
Rare Earth Elements ◽  
Single Crystal ◽  
Kola Peninsula ◽  
Marginal Zone ◽  
X Ray Diffraction ◽  
Eudialyte Group ◽  
X Ray ◽  
Marginal Zones

The Lovozero peralkaline massif (Kola Peninsula, Russia) has several deposits of Zr, Nb, Ta and rare earth elements (REE) associated with eudialyte-group minerals (EGM). Eudialyte from the Alluaiv Mt. often forms zonal grains with central parts enriched in Zr (more than 3 apfu) and marginal zones enriched in REEs. The detailed study of the chemical composition (294 microprobe analyses) of EGMs from the drill cores of the Mt. Alluaiv-Mt. Kedykvyrpakhk deposits reveal more than 70% Zr-enriched samples. Single-crystal X-ray diffraction (XRD) was performed separately for the Zr-rich (4.17 Zr apfu) core and the REE-rich (0.54 REE apfu) marginal zone. It was found that extra Zr incorporates into the octahedral M1A site, where it replaces Ca, leading to the symmetry lowering from R3¯m to R32. We demonstrated that the incorporation of extra Zr into EGMs makes the calculation of the eudialyte formula on the basis of Si + Al + Zr + Ti + Hf + Nb + Ta + W = 29 apfu inappropriate.

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