scholarly journals Structural Investigation into Magnetic Spin Orders of a Manganese Phosphatic Oxyhydroxide, Mn5[(PO4)2(PO3(OH))2](HOH)4

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1688
Author(s):  
Sohyun Park ◽  
Anna Hartl ◽  
Denis Sheptyakov ◽  
Markus Hoelzel ◽  
Ana Arauzo
Keyword(s):  
Structural Investigation ◽  
Magnetic Moments ◽  
Weak Ferromagnetism ◽  
Antiferromagnetic Order ◽  
Small Temperature ◽  
Synthetic Compound ◽  
Space Group ◽  
Magnetic Orders ◽  
Magnetic Spin ◽  
Heat Capacity Measurements

The ferri- and antiferromagnetic structures of a hureaulite-type synthetic compound, Mn2+5(PO4)2(PO3(OH))2(HOH)4, were elucidated by high-resolution neutron powder diffraction in combination with magnetic susceptibility and heat capacity measurements. At 6.17 K, the paramagnetic phase (space group: C2/c) transforms to inherit a ferrimagnetic order (magnetic space group: C2′/c′), followed at 1.86 K by an incommensurately modulated antiferromagnetic order (magnetic superspace group: P21/c.1′(α0γ)00s with the propagation vector k(0.523(2), 0, 0.055(1)). In the ferrimagnetic state, antiferromagnetic interactions are dominant for both intra and inter pentamers of Mn2+(O, HOH)6 octahedra. Differently aligned spin-canting sublattices seen in the ferrimagnetic models at 3.4, 4.5, and 6.1 K explain a weak ferromagnetism in the title compound. The observation of magnetic moments vigorously changing in a small temperature range of 6.1–1.5 K adumbrates a high complexity of interplaying structural and magnetic orders in this manganese phosphatic oxyhydroxide.

scholarly journals Investigation of the Orbital and magnetic orderings in VF3

2014 ◽  
Vol 70 (a1) ◽  
pp. C1367-C1367
Author(s):  
Gwilherm Nénert ◽  
Patrick Reuvekamp ◽  
Christina Drathen ◽  
Roland Eger ◽  
F Kraus ◽  
...  
Keyword(s):  
Phase Transition ◽  
Heat Capacity ◽  
Structural Investigation ◽  
Magnetic Moments ◽  
Neutron Powder Diffraction ◽  
Antiferromagnetic Order ◽  
Magnetic Frustration ◽  
First Order ◽  
First Order Phase Transition ◽  
First Order Phase

We report on a magnetic and structural investigation of layered antiferromagnetic system vanadium (III) fluoride. VF3 crystallizes in a distorted ReO3 structure (R-3c) with rotated undistorted VF6 octahedra. The V3+ cations are arranged in a triangular lattice with the possibility of exhibiting magnetic frustration. Polycrystalline samples of VF3 were investigated using heat capacity, dielectric, magnetic susceptibility, synchrotron and neutron powder diffraction methods. Combining our results, we report the first evidence for a first order phase transition resulting from the ordering of the t2g orbitals below 105-110 K. This transition reduces the symmetry to C2/c. We further confirm that VF3 undergoes a long-range antiferromagnetic order at ∼19 K in accordance with literature [1]. The antiferromagnetic order results in a magnetic structure with the magnetic moments alternating between a parallel and b parallel alignments in the ab plane.

scholarly journals Mode-crystallography analysis and magnetic structures of SrLnFeRuO6 (Ln = La, Pr, Nd) disordered perovskites

2012 ◽  
Vol 68 (6) ◽  
pp. 590-601 ◽  
Author(s):  
E. Iturbe-Zabalo ◽  
O. Fabelo ◽  
M. Gateshki ◽  
J. M. Igartua
Keyword(s):  
Room Temperature ◽  
Magnetic Moments ◽  
Structural Phase ◽  
Magnetic Ordering ◽  
Antiferromagnetic Order ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Magnetic Structures ◽  
Second Order Transition ◽  
The Ideal

The crystal and magnetic structures of SrLnFeRuO6 (Ln = La, Pr, Nd) double perovskites have been investigated. All compounds crystallize with an orthorhombic Pbnm structure at room temperature. These materials show complete chemical disorder of Fe and Ru cations for all compounds. The distortion of the structure, relative to the ideal cubic perovskite, has been decomposed into distortion modes. It has been found that the primary modes of the distortion are octahedral tilting modes: R + 4 and M + 3. The crystal structure of SrPrFeRuO6 has been studied from room temperature up to 1200 K by neutron powder diffraction. There is a structural phase transition from orthorhombic (space group Pbnm) to trigonal (space group R\bar{3}c) at T = 1075 K. According to group theory no second-order transition is possible between these symmetries. Magnetic ordering for all the compounds is described by the magnetic propagation vector (0,0,0). SrPrFeRuO6 shows ferrimagnetic order below ca 475 K, while SrLaFeRuO6 (below ca 450 K) and SrNdFeRuO6 (below ca 430 K) exhibit canted-antiferromagnetic order. The magnetic moments at low temperatures are m(Fe/Ru) = 1.88 (3)μB for SrLaFeRuO6 (2 K), m(Pr) = 0.46 (4)μB and m(Fe/Ru) = 2.24μB for SrPrFeRuO6 (2 K), and m(Fe/Ru) = 1.92μB for SrNdFeRuO6 (10 K).

Magnetic and electric properties of multiferroic LiFeP2O7. Comparison with LiCrP2O7

2021 ◽  
pp. 2150158
Author(s):  
A. T. Apostolov ◽  
I. N. Apostolova ◽  
J. M. Wesselinowa
Keyword(s):  
Magnetic Field ◽  
Magnetoelectric Effect ◽  
Indirect Evidence ◽  
Weak Ferromagnetism ◽  
Electric Properties ◽  
Function Technique ◽  
Antiferromagnetic Order ◽  
Magnetoelectric Properties ◽  
Magnetic Orders ◽  
Magnetic And Electric Properties

The temperature and magnetic field dependence of the magnetic and electric properties of LiFeP2O7 (LFPO) and LiCrP2O7 (LCPO) are studied using a microscopic model and the Green’s function technique. We have shown that LFPO is antiferromagnetic, but shows a weak ferromagnetism along the [Formula: see text] axis which originates from the canted antiferromagnetic order. For LCPO, such a ferromagnetic order along the [Formula: see text] axis is not observed. In the temperature dependence of the electrical polarization [Formula: see text] along the [Formula: see text] axis there is a kink at [Formula: see text] K which is an indirect evidence for the intrinsic magnetoelectric effect in LFPO. Applying an external magnetic field [Formula: see text], the polarization [Formula: see text] increases, stronger for small temperatures and the kink at [Formula: see text] disappears. For LCPO, we do not obtain a kink at [Formula: see text] K. LCPO is polar, but not ferroelectric. We can conclude that the missing magnetoelectric properties in LCPO could be due to the differences in the magnetic orders between LFPO and LCPO.

An HREM study of superstructures in Ca4Al6SO16

1990 ◽  
Vol 48 (4) ◽  
pp. 1066-1067
Author(s):  
Y.G. Wang ◽  
H.Q. Ye ◽  
K.H. Kuo
Keyword(s):  
Calcium Aluminate ◽  
Structural Model ◽  
Bright Spot ◽  
Sulphur Atom ◽  
Synthetic Compound ◽  
Space Group ◽  
Lattice Images ◽  
Cubic Structure ◽  
Good Agreement

A synthetic compound Ca4Al6SO16 (usually abbreviated as C4A3S) obtained by mixing CaO, A12O3 and CaSO4 powders and finally sintered at 1380°C is a cement with excellent hydraulicity and greatly expanding in application. It is hydralysed rapidly by water to form predominatly calcium aluminate hydrates and therefore unlikly to occur naturally, although structurally it may be regarded as an end member of the sodalite-hauynite series of naturally occuring minerals. C4A3S has a cubic structure with ao=9.19Å and space group . Fig.1 is the projection viewed down axis, in which there are two sets of 8C position in , namely CaI and CaII, occupied by the calcium atoms, respectively, and the ratio of occupations in these two sets of positions is about 3:1. This suggests that the calcium atoms can freely occupy these sites in various degrees and usually they almost locates on the CaI positions. A through-focus series of the lattice images were found in good agreement with the simulated ones. Each bright spot in the image taken at Scherzer defocus correspounds to a colunm of sulphur atom in the structural model (Fig.1).

High-pressure / High-temperature Studies on the Stannides RENiSn (RE = Ce, Pr, Nd, Sm) and REPdSn (RE = La, Pr, Nd)

2008 ◽  
Vol 63 (6) ◽  
pp. 695-706 ◽  
Author(s):  
Jan F. Riecken ◽  
Gunter Heymann ◽  
Wilfried Hermes ◽  
Ute Ch. Rodewald ◽  
Rolf-Dieter Hoffmann ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Magnetic Moments ◽  
Structural Data ◽  
Normal Pressure ◽  
Space Group ◽  
Type Space ◽  
High Pressure Phase Transition ◽  
High Pressure High Temperature ◽  
Rare Earth Coordination

The normal-pressure (NP) orthorhombic TiNiSi-type (space group Pnma) stannides RENiSn (RE = Ce, Pr, Nd, Sm) and REPdSn (RE = La, Pr, Nd) were transformed into the corresponding hexagonal ZrNiAl-type (space group P6̄2m) high-pressure (HP) modifications under multianvil high-pressure (7.5 - 11.5 GPa) high-temperature (1100 - 1200 °C) conditions. The structures of NP-CeNiSn, HPPrNiSn, NP-NdNiSn, HP-LaPdSn, HP-PrPdSn, and HP-NdPdSn were refined from single crystal X-ray diffractometer data. Structural data for HP-SmNiSn were obtained from a Rietveld powder refinement. The high-pressure phase transition significantly changes the rare earth coordination, i. e. 4 RE + 6 Ni(Pd) + 6 Sn atoms for the NP-phases and 6 RE + 5 Ni(Pd) + 6 Sn atoms for the HPphases. Susceptibility measurements of HP-PrPdSn and HP-NdPdSn reveal paramagnetic behavior with experimental magnetic moments of 3.61(1) μB/Pr atom and 3.66(1) μB/Nd atom, respectively. Low-temperature susceptibility and specific heat data point to inhomogeneous magnetism and spinglass behavior, respectively.

IR-spektroskopische und kristallstrukturelle Untersuchungen an 2.4-Pentandionato-Lithium-(Li-acac)-Einkristallen / IR-Spectroscopic and X-Ray Structural Investigation of 2,4-Pentandionato-Lithium (Li-acac) Single Crystals

1971 ◽  
Vol 26 (6) ◽  
pp. 528-530 ◽  
Author(s):  
E. Funck ◽  
A. Jungermann ◽  
J. Kaiser ◽  
F. A. Schröder
Keyword(s):  
Ir Spectra ◽  
Single Crystals ◽  
Molecular Species ◽  
Structural Investigation ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Ir Reflection ◽  
Ir Spectroscopic

Single crystals of Li-acetylacetonate (Li-acac) were characterised by microscopical, IR-reflection and X-ray diffraction measurements.The space group was found to be C cca (orthorhombic). From the IR-spectra (polarised radiation) and the properties of the space group the probable arrangements of the molecular species in the crystal are deduced.

Synthesis, structure, and reactivity of macro cyclic heterobimetallic complexes of (Co, Cu), (Co, Ni), (Co, Zn), (Zn, Cu), (Zn, Ni) combinations

1999 ◽  
Vol 77 (1) ◽  
pp. 37-56 ◽  
Author(s):  
H Golchoubian ◽  
W L Waltz ◽  
J W Quail
Keyword(s):  
Crystal Structures ◽  
Magnetic Moments ◽  
Emission Spectra ◽  
Direct Methods ◽  
Chloride Ion ◽  
Crystal Data ◽  
Space Group ◽  
Heterobimetallic Complexes ◽  
Redox Couples ◽  
Open Site

A series of macrocyclic heterobimetallic complexes of type [Mc(tntnam)Mo](PF6)n and [Mc'(tntnim)Ni](PF6)n where Mc = Co(III) and Zn(II), Mc' = Co(II), Co(III), and Zn(II), and Mo = Ni(II), Cu(II), and Zn(II) have been synthesized and characterized. The macrocyclic ligands tntnim 2 and tntnam 3 contain two geometrically distinct compartments, 6-coordinate (closed site) and 4-coordinate (open site), which are bridged by phenolic oxygens. The heterobimetallic complexes with Zn(II) or Ni(II) in the open site are primarily formed as 5-coordinate with a chloride ion as a fifth ligand; the latter can be removed by Ag+ ion. The crystal structures of [Zn(tntnim)NiCl]PF6·C2H5OH, 5, [Zn(tntnam)Ni](PF6)2, 11, [Zn(tntnam)Cu](PF6)2, 12, and [Co(tntnam)Ni(H2O)](PF6)3·4H2O, 14 were determined. Crystal data for 5: monoclinic, T = 123 K, a = 15.822(2), b = 15.6230(10), c = 16.432(2) Å, β = 104.570(10)°, Z = 4, space group Pc, R = 0.0371 (wR2 = 0.0843) for 5826 reflections with I [Formula: see text] 2σ(I). Crystal data for 11: tetragonal, T = 123 K, a = b = 24.122(2), c = 14.397(7) Å, Z = 8, space group P41212, R = 0.0625 (wR2 = 0.1549) for 3250 reflections with I [Formula: see text] 2σ(I). Crystal data for 12: tetragonal, T = 123 K, a = b = 24.180(2), c = 14.281(4) Å, Z = 8, space group P41212, R = 0.0588 (wR2 = 0.1219) for 3452 reflections with I [Formula: see text] 2σ(I). Crystal data for 14: triclinic, T = 287 K, a = 12.664(2), b = 12.983(2), c = 16.216(3) Å, α = 80.317(14)°, β = 69.585(12)°, γ = 74.791(12)°, Z = 2, space group P[Formula: see text], R = 0.0573 (wR2 = 0.1332) for 3443 reflections with I [Formula: see text] 2σ(I). The structures were solved by direct methods and refined by full-matrix least-squares procedures. The crystal structures demonstrate that the expected trans pyridine structures are formed. The magnetic moments, electrospray mass spectra, electronic absorption and emission spectra, and redox couples are reported. Key words: cobalt, copper, nickel, zinc, heterobimetallic, macrocycle.

Magnetic Properties and Specific Heat Studies of the Plumbides CeTPb (T = Cu, Pd, Ag, Au)

2007 ◽  
Vol 62 (7) ◽  
pp. 901-906 ◽  
Author(s):  
Wilfried Hermes ◽  
Sudhindra Rayaprol ◽  
Rainer Pöttgen
Keyword(s):  
Magnetic Properties ◽  
Specific Heat ◽  
High Frequency ◽  
Magnetic Moments ◽  
Type Structure ◽  
Space Group ◽  
Structure Space ◽  
Trivalent Cerium ◽  
Gold Compounds

Abstract The cerium plumbides CeCuPb, CePdPb, CeAgPb, and CeAuPb have been synthesized from the elements in sealed tantalum tubes in a high-frequency furnace followed by annealing. The copper, silver and gold compounds crystallize with the NdPtSb-type structure, space group P63mc: a = 466.1(2), c = 778.1(3) pm for CeCuPb, a = 484.8(2), c = 773.0(3) pm for CeAgPb, and a = 480.24(9), c = 772.9(2) pm for CeAuPb. CePdPb crystallizes with the ZrNiAl-type structure: P6̅2m, a = 775.0(2), c = 413.32(8) pm. The dc susceptibility measurements show trivalent cerium for all four plumbides with experimental magnetic moments of 2.53(2), 2.71(2), 2.63(2), and 2.58(2) μB/Ce atom for CeCuPb, CePdPb, CeAgPb, and CeAuPb, respectively. The compounds CeCuPb, CeAgPb, and CeAuPb, studied by dc susceptibility and specific heat measurements, order antiferromagnetically at N´eel temperatures of 8.2(1), 7.4(1), and 3.7(1) K, respectively.

scholarly journals Anisotropic Ferroelectric Distortion Effects on the RKKY Interaction in Topological Crystalline Insulators

2020 ◽  
Author(s):  
Hosein Cheraghchi ◽  
Mohsen Yarmohammadi
Keyword(s):  
Magnetic Properties ◽  
Symmetry Breaking ◽  
Mirror Symmetry ◽  
Magnetic Moments ◽  
Rkky Interaction ◽  
Dirac Materials ◽  
Nontrivial Behavior ◽  
Magnetic Orders ◽  
Mass Terms ◽  
Topological Crystalline Insulators

Abstract Manipulation of electronic and magnetic properties of topological materials is a topic of much interest in spintronic and valleytronic applications. Perturbation tuning of multiple Dirac cones on the (001) surface of topological crystalline insulators (TCIs) is also a related topic of growing interest. Here we show the numerical evidence for the ferroelectric structural distortion effects on the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between two magnetic impurity moments on the SnTe (001) and related alloys. The mirror symmetry breaking between Dirac cones induced by the ferroelectric distortion could be divided into various possible configurations including the isotropically gapped, coexistence of gapless and gapped, and anisotropically gapped phases. Based on the retarded perturbed Green’s functions of the generalized gapped Dirac model, we numerically find the RKKY response for each phase. The distortion-induced symmetry breaking constitutes complex and interesting magnetic responses between magnetic moments compared to the pristine TCIs. In the specific case of coexisted gapless and gapped phases, a nontrivial behavior of the RKKY interaction is observed, which has not been seen in other Dirac materials up until now. For two impurities resided on the same sublattices, depending on the distortion strength, magnetic orders above of a critical impurity separation exhibit irregular ferromagnetic $ antiferromagnetic phase transitions. However, independent ofthe impurity separation and distortion strength, no phase transition emerges for two impurities resided on different sublattices. This essential study sheds light on magnetic properties of Dirac materials with anisotropic mass terms and also makes TCIs applications relatively easy to understand.

Magnetism,Magnetotransport and Magnetic Structure of ThCu3Mn4O12, Prepared at Moderate Pressures

2008 ◽  
Vol 63 (6) ◽  
pp. 655-660 ◽  
Author(s):  
Javier Sánchez-Benítez ◽  
María J. Martínez-Lope ◽  
José A. Alonso
Keyword(s):  
Crystal Structure ◽  
Magnetic Structure ◽  
Conduction Band ◽  
Magnetic Moments ◽  
Parent Compound ◽  
Mixed Valence ◽  
Complex Perovskite ◽  
Space Group ◽  
Saturation Magnetisation ◽  
Electronic Injection

The complex perovskite ThCu3Mn4O12 has been prepared at moderate pressures of 2 GPa. With respect to the parent compound CaCu3Mn4O12, the replacement of Ca2+ by Th4+ involves a double electronic injection that leads to a substantial increment of TC, up to 370 K. The crystal structure was refined in the space group Im3̄ from NPD data collected with λ = 1.33 Å at r. t. An additional NPD pattern recorded at 1.8 K with λ = 2.42 Å allowed to refine the magnetic structure, which displays a ferrimagnetic coupling between Mn3+/Mn4+ and Cu2+ spins, aligned along the c direction. The refined magnetic moments at the Mn and Cu substructures of 2.5 and −0.5 μB, respectively, account for the observed saturation magnetisation at 2 K, of 7 μB/f. u. A semiconducting behaviour is observed between 10 and 350 K which can be correlated with the appearance of a gap in the conduction band for the ~50% Mn3+/50% Mn4+ mixed valence observed in the B substructure of this perovskite.

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