Ferromagnetic Ordering in CeZnSn

2009 ◽  
Vol 64 (2) ◽  
pp. 175-183 ◽  
Author(s):  
Wilfried Hermes ◽  
Samir F. Matar ◽  
Thomas Harmening ◽  
Ute Ch. Rodewald ◽  
Matthias Eul ◽  
...  
Keyword(s):  
Magnetic Moments ◽  
Magnetic Hyperfine Field ◽  
Induction Melting ◽  
X Ray ◽  
Magnetic Structures ◽  
Bonding Analysis ◽  
Ferromagnetic Ground State ◽  
Weak Interlayer ◽  
Ferromagnetic Ordering ◽  
Experimental Magnetic Moment

The stannide CeZnSn was obtained in X-ray-pure form by induction-melting of the elements in a sealed tantalum ampoule. CeZnSn crystallizes with the YPtAs-type structure, space group P63/mmc, a = 456.7(3), c = 1673.8(5) pm, wR2 = 0.0862, 259 F2 values, and 12 variables. The zinc and tin atoms build up puckered Zn3Sn3 hexagons (Zn-Sn 271 pm) with weak interlayer Zn-Zn interactions (323 pm). Susceptibility measurements of CeZnSn reveal modified Curie-Weiss behavior above 50 K with an experimental magnetic moment of 2.77(1) μB / Ce atom. The cerium magnetic moments order ferromagnetically at TC = 5.2(1) K. 119Sn Mössbauer spectra show a single tin site at an isomer shift of δ = 1.967(4) mm/s subjected to a small quadrupole splitting of ΔEQ = 0.41(2) mm/s at 40 K. At 4.2 K a magnetic hyperfine field of 0.872(5) T is transferred to the tin site. From DFT scalar relativistic calculations of the electronic and magnetic structures, chemical bonding analysis reveals on one hand a weaker bonding of Zn than of Sn with the cerium substructures with a twice stronger Ce1-Sn bond compared to Ce2-Sn. On the other hand, a ferromagnetic ground state is identified from total energy differences in agreement with experiment

Rare Earth-Transition Metal Indides with Lu5Ni2In4-type Structure

2008 ◽  
Vol 63 (12) ◽  
pp. 1447-1449 ◽  
Author(s):  
Roman Zaremba ◽  
Wilfried Hermes ◽  
Matthias Eul ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Transition Metal ◽  
Powder Diffraction ◽  
Magnetic Moment ◽  
Magnetic Moments ◽  
Type Structure ◽  
Induction Melting ◽  
X Ray ◽  
Arc Melting ◽  
Experimental Magnetic Moment

New intermetallic compounds RE5T2In4 (RE = Sc, Y, La-Nd, Sm, Gd-Tm, Lu; T = Rh, Ir) were synthesized by arc-melting of the elements or by induction melting of the elements in tantalum crucibles under flowing argon. The samples were characterized by X-ray powder diffraction. They crystallize with the orthorhombic Lu5Ni2In4-type structure, space group Pbam, Z = 2, a 2 : 1 intergrowth variant of CsCl and AlB2 related slabs of compositions InRE8 (distorted cubes) and RhRE6 (distorted trigonal prisms). Susceptibility measurements of Ce5Ir2In4 have revealed modified Curie- Weiss behavior above 70 K with an experimental magnetic moment of 2.45(1) μB / Ce atom. The cerium magnetic moments order ferri- or ferromagnetically at TC = 7.1(2) K.

scholarly journals Magnetic Transitions in the Co-Modified Mn2Sb System

Inorganics ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 113 ◽  
Author(s):  
Johanna Wilden ◽  
Andreas Hoser ◽  
Mamuka Chikovani ◽  
Jörg Perßon ◽  
Jörg Voigt ◽  
...  
Keyword(s):  
Phase Transition ◽  
Magnetic Moments ◽  
Induction Melting ◽  
Magnetic Structures ◽  
Co Substitution ◽  
First Order Phase Transition ◽  
Phase Transition Temperatures ◽  
Underlying Mechanisms ◽  
The Individual ◽  
First Order Phase

Mn2Sb is ferrimagnetic below its Curie temperature (TC) and passes through a spin flip transition with decreasing temperature. The Co substitution induces an additional first-order phase transition from the ferrimagnetic (FRI) to an antiferromagnetic (AFM) state. This phase transition is connected to a sizable magnetocaloric effect (MCE). To understand the underlying mechanisms, the temperature dependence of structural and magnetic changes was analyzed. At the same time, the influence of the Co substitution was explored. Three Mn2−xCoxSb (x = 0.1, 0.15, 0.2) compounds were synthesized by cold crucible induction melting. Neutron powder diffraction was performed to determine the magnetic structures and to obtain the individual magnetic moments on both symmetrically independent Mn sites. In combination with the temperature-dependent magnetization measurements, the magnetic phase transition temperatures were identified. In the low-temperature range, additional antiferromagnetic peaks were detected, which could be indexed with a propagation vector of (0 0 ½). In Mn1.9Co0.1Sb at 50 K and in Mn1.8Co0.2Sb at 200 K, a co-existence of the FRI and the AFM state was observed. The pure AFM state only occurs in Mn1.8Co0.2Sb at 50 K.

Nickel-deficient Stannides Eu2Ni2–xSn5 – Structure, Magnetic Properties, and Mössbauer Spectroscopic Characterization

2009 ◽  
Vol 64 (10) ◽  
pp. 1107-1114 ◽  
Author(s):  
Thomas Harmening ◽  
Matthias Eul ◽  
Rainer Pöttgen
Keyword(s):  
Solid Solution ◽  
Magnetic Properties ◽  
Powder Diffraction ◽  
Spectroscopic Characterization ◽  
Structure Type ◽  
Induction Melting ◽  
X Ray ◽  
Antiferromagnetic Ordering ◽  
Divalent Europium ◽  
Experimental Magnetic Moment

New nickel-deficient stannides Eu2Ni2−xSn5 were synthesized by induction melting of the elements in sealed tantalum tubes. The solid solution was studied by X-ray powder diffraction and two crystal structures were refined on the basis of X-ray diffractometer data: Cmcm, a = 466.03(4), b = 3843.1(8), c = 462.92(9) pm, wR2 = 0.0469, 692 F2 values, 39 variables for Eu2Ni1.49(1)Sn5 and a = 466.11(9), b = 3820.1(8), c = 462.51(9) pm, wR2 = 0.0358, 695 F2 values, 39 variables for Eu2Ni1.35(1)Sn5. This new structure type can be considered as an intergrowth structure of CaBe2Ge2- and CrB-related slabs. The striking structural motifs are nickel-centered square pyramids which are condensed via common corners and edges. The layers of condensed NiSn5 units are separated by the europium atoms. The Ni1 sites within the CaBe2Ge2 slabs show significant defects which leads to split positions for one tin site. Eu2Ni1.50Sn5 shows Curie-Weiss behavior and an experimental magnetic moment of 7.74(1) μB / Eu atom, indicating stable divalent europium, as is also evident from 151Eu Mössbauer spectra. Antiferromagnetic ordering is detected at 3.5 K.

New Intermetallic Compounds RE4Co2Mg3 (RE = Pr, Gd, Tb, Dy) – Syntheses, Structure, and Chemical Bonding

2007 ◽  
Vol 62 (2) ◽  
pp. 162-168 ◽  
Author(s):  
Selcan Tuncel ◽  
Ute Ch. Rodewald ◽  
Samir F. Matar ◽  
Bernard Chevalier ◽  
Rainer Pöttgena
Keyword(s):  
Single Crystal ◽  
Intermetallic Compounds ◽  
Chemical Bonding ◽  
Structural Features ◽  
Induction Melting ◽  
Geometrical Constraint ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bonding Analysis ◽  
Magnesium Compounds

The magnesium compounds RE4Co2Mg3 (RE = Pr, Gd, Tb, Dy) were prepared by induction melting of the elements in sealed tantalum tubes. The samples were studied by powder X-ray diffraction. The structures of the gadolinium and of the terbium compound were refined from single crystal diffractometer data: Nd4Co2Mg3-type, P2/m, Z = 1, a = 754.0(4), b = 374.1(1), c = 822.5(3) pm, β = 109.65(4)°, wR2 = 0.0649, 730 F2 values for Gd4Co2Mg3 and a = 750.4(2), b = 372.86(6), c = 819.5(2) pm, β = 109.48(3)°, wR2 = 0.0398, 888 F2 values for Tb4Co2Mg3 with 30 variables each. The RE4Co2Mg3 structures are 3 : 1 intergrowth variants of distorted CsCl and AlB2 related slabs of compositions REMg and RECo2. Characteristic structural features (exemplary for Tb4Co2Mg3) are relatively short Tb-Co (271 pm), Co-Co (232 pm) and Mg-Mg (314 pm) distances. The latter are a geometrical constraint of the distortion of the REMg and RECo2 slabs. Chemical bonding analysis (ELF and ECOV data) for Gd4Co2Mg3 reveals strong Gd-Co bonding followed by Mg-Co, while the Mg-Mg interactions can be considered as weak. The Co-Co contacts are only weakly bonding. The bonding and antibonding states are almost filled.

Synthesis, Structure, and Magnetic Properties of EuAgCd and YbAgCd

2001 ◽  
Vol 56 (7) ◽  
pp. 598-603 ◽  
Author(s):  
◽  
Gunter Kotzyba ◽  
Rolf-Dieter Hoffmann ◽  
Rainer Pöttgen
Keyword(s):  
High Frequency ◽  
Small Difference ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dimensional Network ◽  
Pauli Paramagnetism ◽  
Long Range Ordering ◽  
Ferromagnetic Ordering ◽  
Experimental Magnetic Moment

Abstract New intermetallic compounds EuAgCd and YbAgCd were synthesized in quantitative yield by reaction of the elements in sealed tantalum tubes in a high-frequency furnace. Both com­ pounds were investigated by X-ray diffraction on powders and single crystals: KHg2 type, Imma, a = 490.41(8), b = 771.0(1), c = 834.4(2) pm, wR2 = 0.0624, 255 F2 values, 12 variables for EuAgCd, and MgZn2 type, Pb3/mmc, a = 584.66(5), c = 946.83(9) pm, wR2 = 0.0502, 187 F2 values, 11 variables for YbAgCd. Owing to the very small difference in scattering power, no long range ordering of the silver and cadmium atoms is evident from the X-ray data, although Ag-Cd ordering is expected. The silver and cadmium atoms randomly occupy the mercury and zinc positions of the KHg2 and MgZn2 type structures, respectively. In EuAgCd the [AgCd] substructure consists of strongly puckered, orthorhombically distorted Ag3 Cd3 hexagons, while a three-dimensional network of face-and comer-sharing tetrahedra is observed in YbAgCd. The rare earth atoms fill the space between the Ag3 Cd3 hexagons (EuAgCd) or within the three-dimensional tetrahedral network (YbAgCd). Magnetic susceptibility measurements in­ dicate Pauli paramagnetism for YbAgCd and Curie-Weiss behavior above 60 K for EuAgCd with an experimental magnetic moment of 7.82(3) μB/Eu indicating divalent ytterbium and europium. Ferromagnetic ordering at Tc = 28.0(5) K is observed for EuAgCd. At 2 K and 5 T the saturation magnetization is 5.85(5) μB/Eu.

GdCuMg with ZrNiAl-type structure – an 82.2 K ferromagnet

2017 ◽  
Vol 72 (7) ◽  
pp. 511-515 ◽  
Author(s):  
Sebastian Stein ◽  
Lukas Heletta ◽  
Rainer Pöttgen
Keyword(s):  
Magnetic Susceptibility ◽  
Single Crystal ◽  
Magnetic Moment ◽  
Type Structure ◽  
Induction Melting ◽  
X Ray Diffraction ◽  
Muffle Furnace ◽  
Temperature Dependent ◽  
X Ray ◽  
Experimental Magnetic Moment

AbstractGdCuMg has been synthesized by induction-melting of the elements in a sealed niobium ampoule followed by annealing in a muffle furnace. The sample was studied by powder and single crystal X-ray diffraction: ZrNiAl type, P6̅2m (a=749.2(4), c=403.3(1) pm), wR2=0.0242, 315 F2 values and 15 variables. Temperature dependent magnetic susceptibility measurements have revealed an experimental magnetic moment of 8.54(1) μB per Gd atom. GdCuMg orders ferromagnetically below TC=82.2(5) K and based on the magnetization isotherms it can be classified as a soft ferromagnet.

Antiferromagnetic ordering in the plumbide EuPdPb

2017 ◽  
Vol 72 (12) ◽  
pp. 989-994
Author(s):  
Lukas Heletta ◽  
Steffen Klenner ◽  
Theresa Block ◽  
Rainer Pöttgen
Keyword(s):  
Magnetic Susceptibility ◽  
Magnetic Hyperfine Field ◽  
Metamagnetic Transition ◽  
Muffle Furnace ◽  
Temperature Dependent ◽  
X Ray ◽  
Antiferromagnetic Ordering ◽  
Divalent Europium ◽  
Polycrystalline Form ◽  
Experimental Magnetic Moment

AbstractThe plumbide EuPdPb was synthesized in polycrystalline form by reaction of the elements in a sealed niobium ampoule in a muffle furnace. The structure was refined from single-crystal X-ray diffractometer data: TiNiSi type, Pnma, a=752.4(2), b=476.0(2), c=826.8(2) pm, wR2=0.0485, 704 F2 values and 20 variables. The europium atoms are coordinated by two tilted and puckered Pd3Pb3 hexagons (280–289 pm Pd–Pb) with pronounced Eu–Pd bonding (312–339 pm). Temperature-dependent magnetic susceptibility measurements show Curie-Weiss behaviour and an experimental magnetic moment of 7.35(1) μB per Eu atom. EuPdPb orders antiferromagnetically at TN=13.8(5) K and shows a metamagnetic transition at a critical field of 15 kOe. 151Eu Mössbauer spectra confirm divalent europium (δ=–10.04(1) mm s−1) and show full magnetic hyperfine field splitting (Bhf=21.1(1) T) at 6 K.

Intermetallic Cadmium Compounds M5T2Cd (M = Ca, Yb, Eu; T = Cu, Ag, Au) with Mo5B2Si-type Structure

2011 ◽  
Vol 66 (12) ◽  
pp. 1219-1224
Author(s):  
Frank Tappe ◽  
Christian Schwickert ◽  
Matthias Eul ◽  
Rainer Pöttgen
Keyword(s):  
Magnetic Moments ◽  
Small Degree ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Antiferromagnetic Ordering ◽  
Pauli Paramagnetism ◽  
Slab Temperature ◽  
Experimental Magnetic Moment ◽  
The Eu

The intermetallic compounds M5T2Cd (M = Ca, Yb, Eu; T = Cu, Ag, Au) and Yb5Cu2Zn were synthesized by melting the elements in sealed tantalum tubes followed by annealing at 923 K. All phases were characterized on the basis of powder and single-crystal X-ray diffraction data: Mo5B2Si type, I4/mcm, Z = 4, a = 828.7(1), c = 1528.1(3) pm, wR2 = 0.030, 440 F2 values, 16 variables for Eu5Cu2Cd, a = 788.2(1), c = 1459.3(5) pm, wR2 = 0.053, 378 F2 values, 16 variables for Yb5Cu2Cd, and a = 797.2(1), c = 1438.8(3) pm, wR2 = 0.036, 386 F2 values, 17 variables for Yb5Au2.19Cd0.81, which shows a small degree of Au / Cd mixing. The M5T2Cd structures are intergrowth variants of slightly distorted CuAl2- and U3Si2-related slabs. Striking coordination motifs (exemplary for Eu5Cu2Cd) are square antiprisms of the Eu atoms around Cd, Eu8 square prisms around Eu, and trigonal Eu6 prisms around Cu within the AlB2-related slab. Temperature-dependent magnetic susceptibility measurements showed Pauli paramagnetism for Yb5Cu2Zn, indicating purely divalent ytterbium. Eu5Au2Cd exhibits Curie-Weiss behavior above 100 K with an experimental magnetic moment of 8.14 μB per Eu atom and a Weiss constant of 56 K. Antiferromagnetic ordering of the EuII magnetic moments is evident at 36 K, and a metamagnetic transition is observed at 25 K and 13 kOe.

Rare earth-rhodium-plumbides RE2Rh2Pb with RE = La–Nd, Sm, Gd and Tb

2018 ◽  
Vol 73 (12) ◽  
pp. 1015-1021 ◽  
Author(s):  
Lukas Heletta ◽  
Rainer Pöttgen
Keyword(s):  
Room Temperature ◽  
Magnetic Moments ◽  
Induction Melting ◽  
Temperature Dependent ◽  
X Ray ◽  
Conduction Electrons ◽  
Paramagnetic Behavior ◽  
Arc Melting ◽  
Intergrowth Structures

AbstractThe plumbides RE2Rh2Pb (RE = La–Nd, Sm, Gd, Tb) were synthesized in sealed niobium ampoules by induction melting of the pure elements or directly via arc-melting. The characterization of the samples by X-ray powder diffraction confirmed their Mo2B2Fe-type structure (space group P4/mbm) at room temperature. The Sm2Rh1.924Pb structure was refined from single-crystal X-ray diffractometer data: a=760.02(5), c=378.20(3) pm, wR=0.0387, 292 F2 values, 13 variables. The rhodium site shows small defects. The RE2Rh2Pb plumbides are simple 1:1 intergrowth structures of AlB2 and CsCl related slabs of compositions RERh2 and REPb. The Rh2 dumbbell in the SmRh2 slab of Sm2Rh2Pb shows a Rh–Rh distance of 281 pm. Temperature-dependent magnetic susceptibility measurements of La2Rh2Pb, Pr2Rh2Pb and Nd2Rh2Pb showed that the rhodium atoms carry no localized magnetic moments. La2Rh2Pb exhibits Pauli-paramagnetic behavior induced by the conduction electrons. The ground state of the praseodymium compound is ferromagnetic below TC=3.3 K while the neodymium compound shows a transition to an antiferromagnetic state at TN=6.1 K and a metamagnetic transition at a critical field of ca. 1000 Oe.

Rare earth-rich cadmium compounds RE10TCd3 (RE=Y, Tb, Dy, Ho, Er, Tm, Lu; T=Rh, Pd, Ir, Pt) with an ordered Co2Al5-type structure

2018 ◽  
Vol 73 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Theresa Block ◽  
Steffen Klenner ◽  
Lukas Heletta ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Magnetic Moments ◽  
Magnetic Ordering ◽  
Intermetallic Phases ◽  
Induction Melting ◽  
Temperature Dependent ◽  
Interatomic Distances ◽  
X Ray ◽  
Paramagnetic Behavior ◽  
Strong Covalent Bonding

AbstractEighteen new rare earth-rich intermetallic phasesRE10TCd3(RE=Y, Tb, Dy, Ho, Er, Tm, Lu;T=Rh, Pd, Ir, Pt) were obtained by induction melting of the elements in sealed niobium ampoules followed by annealing in muffle furnaces. All samples were characterized by X-ray powder diffraction. The structures of four representatives were refined from single-crystal X-ray diffractometer data: ordered Co2Al5type,P63/mmc,a=951.2(1),c=962.9(2) pm,wR=0.0460, 595F2values, 20 parameters for Er10RhCd3;a=945.17(4),c=943.33(4),wR=0.0395, 582F2values, 21 parameters for Lu9.89PdCd3.11;a=964.16(6),c=974.93(6) pm,wR=0.0463, 614F2values, 21 parameters for Y10Ir1.09Cd2.91;a=955.33(3),c=974.56(3) pm,wR=0.0508, 607F2values, 22 refined parameters for Dy9.92IrCd3.08. Refinements of the occupancy parameters revealed small homogeneity ranges resulting fromRE/Cd, respectivelyT/Cd mixing. The basic building units of theRE10TCd3phases are transition metal-centeredRE6trigonal prisms (TP) that are condensed with double-pairs of emptyRE6octahedra via common triangular faces. A second type of rods is formed by slightly distortedRE3@Cd6RE6icosahedra which are condensed via Cd3triangular faces. The shortest interatomic distances occur forRE–T, compatible with strong covalent bonding interactions. Temperature dependent magnetic susceptibility measurements were performed forRE10RhCd3(RE=Dy–Tm, Lu),RE10IrCd3(RE=Er, Tm, Lu) andRE10PtCd3(RE=Y, Lu). While Y10PtCd3and Lu10TCd3(T=Rh, Ir, Pt) show Pauli paramagnetic behavior, the compounds containing paramagnetic rare earth elements show Curie-Weiss behavior (the experimental magnetic moments indicate stable trivalentRE3+) and magnetic ordering at low temperatures:TC=80.5 K for Dy10RhCd3and Neél temperatures of 42.1, 23.3, 12.6, 5.9, 10.0 K for Ho10RhCd3, Er10RhCd3, Er10IrCd3, Tm10RhCd3, Tm10IrCd3, respectively.

Sign in / Sign up

Export Citation Format

Share Document