scholarly journals Coexistence of Spin Canting and Metamagnetism in a One-Dimensional Mn(II) Compound Bridged by Alternating Double End-to-End and Double End-On Azido Ligands and the Analog Co(II) Compound

2021 ◽  
Vol 7 (4) ◽  
pp. 50
Author(s):  
Nesrine Benamara ◽  
Zouaoui Setifi ◽  
Chen-I Yang ◽  
Sylvain Bernès ◽  
David K. Geiger ◽  
...  
Keyword(s):  
Magnetic Transition ◽  
Magnetic Ordering ◽  
Weak Ferromagnetism ◽  
Molecular Structures ◽  
Spin Canting ◽  
Manganese Compound ◽  
Space Groups ◽  
Antiferromagnetic Ordering ◽  
End To End ◽  
Interchain Interactions

Two new compounds of general formula [M(N3)2(dmbpy)] in which dmbpy = 5,5′-dimethyl-2,2′-bipyridine, and M = Mn(II) or Co(II), have been solvothermally synthesized and characterized structurally and magnetically. The structures consist of zig-zag polymeric chains with alternating bis-µ(azide-N1)2M and bis-µ(azide-N1,N3)2M units in which the cis-octahedrally based coordination geometry is completed by the N,N’-chelating ligand dmbpy. The molecular structures are basically the same for each metal. The Mn(II) compound has a slightly different packing mode compared to the Co(II) compound, resulting from their different space groups. Interestingly, relatively weak interchain interactions are present in both compounds and this originates from π–π stacking between the dmbpy rings. The magnetic properties of both compounds have been investigated down to 2 K. The measurements indicate that the manganese compound shows spin-canted antiferromagnetic ordering with a Néel temperature of TN = 3.4 K and further, a field-induced magnetic transition of metamagnetism at temperatures below the TN. This finding affords the first example of an 1D Mn(II) compound with alternating double end-on (EO) and double end-to-end (EE) azido-bridged ligands, showing the coexistence of spin canting and metamagnetism. The cobalt compound shows a weak ferromagnetism resulting from a spin-canted antiferromagnetism and long-range magnetic ordering with a critical temperature, TC = 16.2 K.

scholarly journals Spin-canting and weak ferromagnetism in two novel 1D alternating chains with single <italic>cis</italic>-end-to-end azido bridges

2012 ◽  
Vol 42 (6) ◽  
pp. 922-923
Author(s):  
Li JIA ◽  
Jin XIONG ◽  
Tao LIU ◽  
HaoLing SUN ◽  
Xue ZHEN ◽  
...  
Keyword(s):  
Weak Ferromagnetism ◽  
Spin Canting ◽  
End To End

scholarly journals Механизм открытия щели в точке Дирака в электронном спектре Gd-допированного топологического изолятора

2020 ◽  
Vol 62 (2) ◽  
pp. 286
Author(s):  
А.М. Шикин ◽  
Д.А. Естюнин ◽  
А.В. Королева ◽  
Д.А. Глазкова ◽  
Т.П. Макарова ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Long Range ◽  
Photoelectron Spectroscopy ◽  
Dirac Point ◽  
Energy Gap ◽  
Magnetic Transition ◽  
Magnetic Ordering ◽  
Photoelectron Spectra ◽  
Dirac Cone ◽  
Antiferromagnetic Ordering

The electronic structure of magnetically-doped TI with stoichiometry Bi1.09Gd0.06Sb0.85Te3 in the region of the Dirac point has been studied in detail by angle-resolved photoelectron spectroscopy (ARPES) at various temperatures (above and below the Néel temperature, 1-35 K) and different polarizations of synchrotron radiation. It has shown that the energy gap in photoemission spectra opens at the Dirac point and remains open above the temperature of the long-range magnetic ordering, Tn. Measurements of magnetic properties by the superconducting magnetometry method (SQUID) have shown antiferromagnetic ordering with a transition temperature to the paramagnetic phase equal to 8.3 K. Study of the temperature dependence of the Dirac cone state intensity at the Г point by ARPES has confirmed the magnetic transition and has shown a possibility of its indication directly from photoemission spectra. A more detailed analysis of the splitting between the upper and lower Dirac cone states (i.e. the energy gap) at the Dirac point in the photoelectron spectra has shown the dependence of the measured gap on the synchrotron radiation polarization (about 28-30 meV for p-polarization and 22-25 meV for circularly polarized radiation of opposite chirality). The mechanism of opening the gap at a Dirac point above the Tn was proposed due to the “pairing” of the Dirac fermions with opposite momentum and spin orientation as a result of their interaction with the spin texture generated by photoemission in the region of the photoemission hole on a magnetic impurity atom (Gd). It was shown that the gap at the Dirac point, measured above Tn, is dynamic and is formed directly during photoemission process. At the same time, the origin of the gap remains magnetic (even when the long-range magnetic ordering is destroyed) and is associated with the properties of the magnetic topological insulator that determines a practically unchanged size of the gap above Tn. The dynamic origin of the generated gap is confirmed by the dependence of its magnitude on the polarization of synchrotron radiation.

Spin-canting and weak ferromagnetism in two novel 1D alternating chains with single cis-end-to-end azido bridges

2012 ◽  
Vol 55 (6) ◽  
pp. 1031-1036 ◽  
Author(s):  
HaoLing Sun ◽  
Jin Xiong ◽  
ShaoFei Ji ◽  
Xue Zhen ◽  
Li Jia ◽  
...  
Keyword(s):  
Weak Ferromagnetism ◽  
Spin Canting ◽  
End To End

First-principles investigation of bandgap tailoring in tetragonal Bi2FeCrO6 by magnetic ordering and B-site-cation ordering

2019 ◽  
Vol 13 (01) ◽  
pp. 1950092
Author(s):  
Lijing Wei ◽  
Jianxin Guo ◽  
Li Guan ◽  
Baoting Liu
Keyword(s):  
First Principles ◽  
Magnetic Ordering ◽  
Stable Structure ◽  
Cation Ordering ◽  
First Principles Calculations ◽  
Antiferromagnetic Ordering ◽  
Long Time ◽  
Application Potential

The development of ferroelectric photovoltaic (FE-PV) materials has been limited for a long time due to their large bandgap. Many strategies for lowering the bandgap have been suggested to promote FE-PV properties. The effects of magnetic ordering and B-site-cation ordering to lower the bandgap of FE-PV are investigated in this paper using first-principles calculations. Results show that the most stable structure of tetragonal Bi2FeCrO6 ([Formula: see text]-Bi2[Formula: see text] is the AS1 structure (Fe/Cr alternate stacking ordering) with C-type antiferromagnetic ordering (defined as AC-[Formula: see text]-Bi2FeCrO6), which has a small bandgap, suggesting that AC-[Formula: see text]-Bi2FeCrO6 is among the FE-PV materials with the highest application potential.

Superconductivity and Magnetic Ordering of Pr in CaLa1-xPrxBaCu3O7 System

1997 ◽  
Vol 11 (07) ◽  
pp. 323-331 ◽  
Author(s):  
V. P. S. Awana ◽  
Rajvir Singh ◽  
D. A. Landinez Tellez ◽  
J. M. Ferreira ◽  
J. Albino Aguiar ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Normal State ◽  
Ac Susceptibility ◽  
Magnetic Ordering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Antiferromagnetic Ordering ◽  
Peak Intensity ◽  
Heat Capacity Measurements ◽  
A Minor

We present the results of superconductivity, normal state magnetic susceptibility and heat capacity measurements on the tetragonal CaLa 1-x Pr x BaCu 3 O 7 compound. Ac susceptibility measurements show that the transition temperature T c of the unsubstituted sample decreases with an increase in the Pr concentration. Normal state dc magnetic susceptibility measurements performed in an applied field of 0.5 T show a Curie–Weiss behaviour in terms of the paramagnetic moment of Pr. The effective paramagnetic moment of Pr appears to be intermediate between those of the free Pr 3+ and Pr 4+ ions. For the nonsuperconducting samples i.e., x = 0.70 and 1.0, we observe an antiferromagnetic ordering temperature T N of nearly 4 K and 8 K respectively. The X-ray diffraction results show that the CaPrBaCu 3 O 7 compound is free from other phases, having a minor (less than 8%, in terms of peak intensity) impurity phase. The lower T N (8 K) of PrBaCaCu 3 O 7 as compared to the known antiferromagnetic ordering temperature of 17 K for PrBa 2 Cu 3 O 7 indicates a less deleterious effect of Pr in the present case.

scholarly journals A historical introduction to the symmetries of magnetic structures. Part 1. Early quantum theory, neutron powder diffraction and the coloured space groups

2017 ◽  
Vol 32 (2) ◽  
pp. 148-155 ◽  
Author(s):  
Andrew S. Wills
Keyword(s):  
Time Reversal ◽  
Magnetic Ordering ◽  
Neutron Powder Diffraction ◽  
Quantum Mechanical ◽  
Langevin Model ◽  
Space Groups ◽  
Magnetic Structures ◽  
Black And White ◽  
Magnetic Symmetry ◽  
Looking Back

This paper introduces the historical development of the symmetries for describing magnetic structures culminating in the derivation of the black and white and coloured space groups. Beginning from the Langevin model of the Curie law, it aims to show the challenges that magnetic ordering presented and how different symmetry frameworks were developed to meet them. As well as explaining core ideas, later papers will show how the different schemes are connected. With these goals in mind, the maths related is kept to the minimum required for clarity. Those wishing to learn more details are invited to engage with the references. As well as looking back and reviewing the development of magnetic symmetry over time, particular attention is spent on explaining where the concept of time-reversal has been applied. That time-reversal has different meaning in classical and quantum mechanical situations, has created confusions which continue to propagate.

THE EFFECT OF OXYGEN ON SUPERCONDUCTIVITY AND MAGNETISM IN Eu1.5Ce0.5RuSr2Cu2O10 +δ

1999 ◽  
Vol 13 (29n31) ◽  
pp. 3650-3654 ◽  
Author(s):  
I. FELNER ◽  
U. ASAF ◽  
Y. LEVI ◽  
O. MILLO
Keyword(s):  
Magnetic Ordering ◽  
Weak Ferromagnetism ◽  
Scanning Tunneling Spectroscopy ◽  
Hole Doping ◽  
Scanning Tunneling ◽  
Normal State Resistivity ◽  
Oxygen Treatment ◽  
Time Scanning ◽  
Effect Of Oxygen ◽  
The Eu

The Eu 1.5 Ce 0.5 RuSr 2 Cu 2 O 10+δ compound is the first known Cu-O based material in which superconductivity (SC) and weak-ferromagnetism (W-FM) coexist (T c =32 K, T M =122 K). SC is confined to the CuO 2 planes, and the magnetic ordering is due to the Ru sublattice. For as-prepared samples (APS), the normal-state resistivity is characteristic of an under-doped SC compound. The hole doping in CuO 2 planes, can be achieved with appropriate variation of the oxygen concentrations, which is obtained by annealing the APS under oxygen pressures up to 150 atm. The effect of oxygen treatment is to shift the onset of SC monotonically, up to 49 K. For 75 atm., two transition temperatures are found, indicating the existence of two SC phases. At the same time, scanning tunneling spectroscopy measurements show spatial variations of the gap with a double-peak distribution.

Lack of a threefold rotation axis in α-Fe2O3and α-Cr2O3crystals

2015 ◽  
Vol 71 (2) ◽  
pp. 203-208 ◽  
Author(s):  
Michał Stękiel ◽  
Radosław Przeniosło ◽  
Izabela Sosnowska ◽  
Andrew Fitch ◽  
Jacek B. Jasiński ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Rotation Axis ◽  
Magnetic Ordering ◽  
Evidence Based ◽  
Space Group ◽  
X Ray ◽  
Space Groups ◽  
Transmission Electron

The crystal structure of α-Fe2O3and α-Cr2O3is usually described with the corundum-type trigonal crystal structure based on the space group R\bar 3c. There are, however, some observations of the magnetic ordering of both α-Fe2O3and α-Cr2O3that are incompatible with the trigonal symmetry. We show experimental evidence based on X-ray powder diffraction and supported by transmission electron microscopy that the symmetry of the crystal structure of both α-Fe2O3and α-Cr2O3is monoclinic and it is described with the space groupC2/c(derived from R\bar 3c by removing the threefold rotation axis). The magnetic orderings of α-Fe2O3and α-Cr2O3are compatible with the magnetic space groupsC2/candC2/c′, respectively. These findings are in agreement with the idea from Curie [(1894),J. Phys.3, 393–415] that the dissymmetry of the magnetic ordering should be associated with a dissymmetry of the crystal structure.

Pillared cobalt–organic framework with an unprecedented (3,4,6)-connected architecture showing the coexistence of spin canting and long-range magnetic ordering

CrystEngComm ◽  
2010 ◽  
Vol 12 (2) ◽  
pp. 395-400 ◽  
Author(s):  
Fu-Ping Huang ◽  
Jin-Lei Tian ◽  
Dong-Dong Li ◽  
Gong-Jun Chen ◽  
Wen Gu ◽  
...  
Keyword(s):  
Long Range ◽  
Magnetic Ordering ◽  
Spin Canting ◽  
Organic Framework

Conformational differences and intermolecular C—H...N interactions in three polymorphs of a bis(pyridinyl)-substituted benzimidazole

2016 ◽  
Vol 72 (11) ◽  
pp. 867-874 ◽  
Author(s):  
David K. Geiger ◽  
Matthew R. DeStefano
Keyword(s):  
Dft Calculations ◽  
Intermolecular Interactions ◽  
Crystal Engineering ◽  
Density Functional ◽  
Molecular Conformation ◽  
Molecular Structures ◽  
Acta Cryst ◽  
Space Groups ◽  
Polymorphic Forms

The structural characterization of several polymorphic forms of a compound allow the interplay between molecular conformation and intermolecular interactions to be studied, which can contribute to the development of strategies for the rational preparation of materials with desirable properties and the tailoring of intermolecular interactions to produce solids with predictable characteristics of interest in crystal engineering. The crystal structures of two new polymorphs of 5,6-dimethyl-2-(pyridin-2-yl)-1-[(pyridin-2-yl)methyl]-1H-benzimidazole, C20H18N4, are reported. The previously reported polymorph, (1) [Geiger & DeStefano (2014).Acta Cryst.E70, o365], exhibits the space groupC2/c, whereas polymorphs (2) and (3) presented here are in thePnmaandP\overline{1} space groups, respectively. The molecular structures of the three forms differ in their orientations of the 2-(pyridin-2-yl)- and 1-[(pyridin-2-yl)methyl]- substituents. Density functional theory (DFT) calculations show that the relative energies of the molecule in the three conformations follows the order (1) < (2) < (3), with a spread of 10.6 kJ mol−1. An analysis of the Hirshfeld surfaces shows that the three polymorphs exhibit intermolecular C—H...N interactions, which can be classified into six types. Based on DFT calculations involving pairs of molecules having the observed interactions, the C—H...N energy in the systems explored is approximately −11.2 to −14.4 kJ mol−1.

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