Magnetic structure of GdCo2Ge2 (original) (raw)
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Journal of Physics: Condensed Matter, 2010
The magnetic structure of GdMn 2 Ge 2 (tetragonal I 4/mmm) has been studied by hot neutron powder diffraction and x-ray resonant magnetic scattering techniques. These measurements, along with the results of bulk experiments, confirm the collinear ferrimagnetic structure with moment direction parallel to the c-axis below T C = 96 K and the collinear antiferromagnetic phase in the temperature region T C < T < T N = 365 K. In the antiferromagnetic phase, x-ray resonant magnetic scattering has been detected at Mn K and Gd L 2 absorption edges. The Gd contribution is a result of an induced Gd 5d electron polarization caused by the antiferromagnetic order of Mn-moments.
Magnetic properties of Gd1−xCexMn2Ge2 compounds
Solid State Communications, 2001
The crystal structure and magnetic properties of polycrystalline Gd 12x Ce x Mn 2 Ge 2 (x 0:0 2 1:0) compounds with the ThCr 2 Si 2 -type structure have been investigated and the magnetic phase diagram has been constructed. The ferromagnetism observed in CeMn 2 Ge 2 transforms to ferrimagnetism with the substitution of Gd for Ce. An additional high temperature ferromagnetic phase in GdMn 2 Ge 2 weakens and eventually disappears with the addition of Ce. The saturation magnetization with increasing x at 4.2 K decreases up to the x 0:5, and then increases again. q
Magnetic properties of GdT2Ge2 compounds (T=3d, 4d)
Journal of Alloys and Compounds, 2000
We have studied the magnetic properties of the GdT Ge compounds (T53d: Fe, Co, Ni, Cu, 4d: Ru, Rh, Pd) by means of DC 2 2 susceptibility and high-field free-powder (HFFP) measurements. All compounds investigated were found to order antiferromagnetically at low temperatures. The two-sublattice model, without anisotropy, has been used to obtain experimental values for the intrasublattice coupling constant n , and the intersublattice exchange coupling constant n . The values of the intersublattice constants derived from the 11 12
The preferential site occupation and magnetic properties of GdxY2−xO3
Journal of Physics and Chemistry of Solids, 1993
Abstra&-The gadolinium-yttrium mixed oxides Gd,Y,_,O, were synthesized over a wide range of concentrations: x = 0.10, 0.18, 0.41, 0.74 and 1.26. The X-ray diffraction data from the polycrystalline samples were taken at room temperature and refined using the Rietveld method. Gadolinium-yttrium oxides crystallize in the space group Ia3. The cations occupy the six coordinated positions 8b and 24d. The anion occupies a general tetrahedrally coordinated position. At concentrations x Q 0.41 gadolinium ion occupies exclusively 24d, but at higher concentrations the occupation of position 86 increases continuously. The magnetic susceptibility measurements showed the presence of the antiferromagnetic interaction in all samples. The magnetic moment in the sample x = 1.26 is significantly different from the magnetic moment of the free ion Gd 3+. The Cur&Weiss temperature shows a nonlinear dependence on concentration.
Physical Review B, 2005
Gd 5 Ge 4 crystallizes in the orthorhombic space group Pnma, and orders antiferromagnetically below the Néel temperature T N ϳ 127 K. We have employed x-ray resonant magnetic scattering to elucidate the details of the magnetic structure. The magnetic unit cell is the same as the chemical unit cell. From azimuth scans and the Q dependence of the magnetic scattering, all three Gd sites in the structure were determined to be in the same magnetic space group PnmЈa. The magnetic moments are primarily aligned along the c axis and the c components of the magnetic moments at the three different sites are equal. The ferromagnetic Gd-rich slabs are stacked antiferromagnetically along the b direction.
Study of structural and magnetic properties of Gd2MoO6 compound
PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS: ICAM 2019, 2019
In this present work, we study the structural, microstructural, electronic and magnetic properties of Gadolinium M olybdate (Gd 2 M oO 6) compound synthesized via solid statereactionmethod. The single-phase nature of the compound is confirmed using x-ray diffraction (XRD) technique and the structure is refined to monoclinic symmetry (C2/c, Space group 15). Surface imaging of the sample shows agranular type morphology of about 0.1 µm.X-ray photoelectron spectroscopic measurements reveal mixed valent (4+/6+) charge states in case of M o and also the presence of oxygen vacancies in Gd 2 M oO 6. M agnetization measurements performed using 7T SQUID VSM reveal an overall antiferromagnetic behavior.
Crystal structure and magnetic properties of GdZn< sub> 2 Ga< sub> 2
2012
Intermetallic compounds of Gd with Si, Ge, and Sn near 1:2 stoichiometry adopt several closely related crystal structures. We find that GdSi 1.78 and Gd(Si 0.684 Ge 0.316) 1.78 crystallize in the same GdSi 1.4-type orthorhombic structure (space group Imma), while GdGe 1.57 and GdSn 2 adopt -ThSi 2-type tetragonal structure (space group I4 1 /amd) and ZrSi 2-type orthorhombic structure (space group Cmcm), respectively. All compounds order antiferromagnetically; their Néel temperatures are only weakly affected by the magnetic field of less than 50 kOe. Unusual features are observed including multiple phase transitions and thermomagnetic irreversibilities.
We investigate the magnetic and electronic properties of the GdT 2 Zn 20 (T = Fe and Co) compounds using X-ray resonant magnetic scattering (XRMS), X-ray absorption near-edge structure (XANES) and X-ray magnetic circular dichroism (XMCD) techniques. The XRMS measurements reveal that the GdCo 2 Zn 20 compound has a commensurate antiferromagnetic spin structure with a magnetic propagation vector τ = ( 1 2 , 1 2 , 1 2 ) below the Néel temperature (T N ∼ 5.7 K). Only the Gd ions carry a magnetic moment forming an antiferromagnetic structure with magnetic representation Γ 6 . For the ferromagnetic GdFe 2 Zn 20 compound, an extensive investigation was performed at low temperature and under magnetic field using XANES and XMCD techniques. A strong XMCD signal of about 12.5 % and 9.7 % is observed below the Curie temperature (T C ∼ 85 K) at the Gd-L 2 and L 3 edges, respectively. In addition, a small magnetic signal of about 0.06 % of the jump is recorded at the Zn K-edge suggesting that the Zn 4p states are spin polarized by the Gd 5d extended orbitals.
Phase formation and ferrimagnetism of GdCo9Si4
2006
The phase relations of the GdCo 13−x Si x system have been studied by means of scanning microscopy, microprobe analysis and x-ray diffraction. Single-phase samples GdCo 9±δ Si 4∓δ (structure type LaFe 9 Si 4 with space group I 4/mcm) are formed in a narrow composition range |δ| 0.2, where GdCo 9 Si 4 forms as a fully ordered ternary compound. The magnetic properties of GdCo 9 Si 4 have been investigated by ac susceptibility, magnetization, specific heat and resistivity measurements. These experiments reveal ferrimagnetism below about 47 K, which is analysed in terms of a two-sublattice molecular field model with a local moment Gd subsystem coupling antiparallel to the itinerant ferromagnetic Co 3d sublattice. The 3d-3d exchange of the latter is the driving force for the onset of long range magnetic order. The validity of the twosublattice model is demonstrated by high field measurements, showing that the ferrimagnetic coupling starts to break up at a lower critical field µ 0 H l 27 T. The magnetic ground state of GdCo 9 Si 4 has been analysed on a microscopic basis via LSDA electronic structure calculations.