Symmetry of Magnetic Structures: Magnetic Structure of Chalcopyrite

1958 ◽  
Vol 112 (6) ◽  
pp. 1917-1923 ◽  
Author(s):  
G. Donnay ◽  
L. M. Corliss ◽  
J. D. H. Donnay ◽  
N. Elliott ◽  
J. M. Hastings
Keyword(s):  
Magnetic Structure ◽  
Magnetic Structures

Magnetic Structure of Manganese Pyrophosphate and Copper Pyrophosphate

1972 ◽  
Vol 50 (24) ◽  
pp. 3079-3084 ◽  
Author(s):  
J. A. R. Stiles ◽  
C. V. Stager
Keyword(s):  
Phase Transition ◽  
Neutron Diffraction ◽  
Single Crystal ◽  
Magnetic Structure ◽  
Magnetic Structures

The magnetic structures of antiferromagnetic manganese pyrophosphate and copper pyrophosphate have been determined by single crystal neutron diffraction techniques. There have been two previous determinations of the structure of manganese pyrophosphate. The discrepancy between these results is explained by postulating a crystallographic phase transition.

Strukturen cäsiumhaltiger Fluoride, II1 Die Kristall- und Magnetische Struktur von CsFeF4 / Crystal and Magnetic Structure of CsFeF4

1974 ◽  
Vol 29 (3-4) ◽  
pp. 139-148 ◽  
Author(s):  
D. Babel ◽  
F. Wall ◽  
G. Heger
Keyword(s):  
Neutron Diffraction ◽  
Single Crystals ◽  
Magnetic Structure ◽  
Structure Determination ◽  
Mean Value ◽  
X Ray ◽  
Magnetic Structures ◽  
Powder Samples ◽  
Crystal And Magnetic Structure ◽  
Improved Model

The results of an X-ray structure determination on single crystals of CsFeF4 are reported. The compound crystallizes tetragonally with α = 7.794, c = 6.553 Å, z = 4, in spacegroup P4/nmm-D4h7 and is a hitherto unknown superstructure variant of the TlAlF4-type. Cesium exhibits 12-coordination (mean value Cs-F = 3.25 Å); the FeF6-octahedra are characteristically shortened normal to the FeF4⁻-layers (Fe-F = 1.962/1.861Å). An improved model is proposed and verified for a related structure of RbFeF4, showing the same features. Neutron diffraction studies on powder samples of CsFeF4 show that both compounds are identical as for their magnetic structures.

Magnetic Phase Diagram in Layered Perovskite Manganite La2-2xSr1+2xMn2O7 (0.313≤x≤0.350)

2006 ◽  
Vol 512 ◽  
pp. 183-188 ◽  
Author(s):  
Takeshi Murata ◽  
Tomoyuki Terai ◽  
Takashi Fukuda ◽  
Tomoyuki Kakeshita
Keyword(s):  
Phase Diagram ◽  
Magnetic Structure ◽  
Easy Axis ◽  
Magnetic Phase ◽  
Magnetic Phase Diagram ◽  
The Other ◽  
Layered Perovskite ◽  
Perovskite Manganites ◽  
Perovskite Manganite ◽  
Magnetic Structures

We have measured the magnetization as a function of temperature and magnetic field in layered perovskite manganites of La2-2xSr1+2xMn2O7 single crystals (x=0.313, 0.315, 0.320, 0.350) in order to know their magnetic structures. All the present manganites exhibit magnetic transitions from ferromagnetic to paramagnetic at 76K, 107K, 120K and 125K for x=0.313, 0.315, 0.320 and 0.350, respectively. For x=0.350 and 0.320, the magnetic structure is a planar ferromagnetism whose easy axis is in the ab-plane at all temperatures below the Curie temperature. On the other hand, for x=0.315 and 0.313, the magnetic structure is an uniaxial ferromagnetism whose easy axis is along the c-axis below 85K and 66K, respectively, and a planar ferromagnetism above the temperature. From the results described above, we made the detailed magnetic phase diagram of layered perovskite manganite La2-2xSr1+2xMn2O7 (0.313≤x≤0.350).

scholarly journals Double antisymmetry in magnetic structures

2014 ◽  
Vol 70 (a1) ◽  
pp. C518-C518
Author(s):  
Brian VanLeeuwen ◽  
Mantao Huang ◽  
Daniel Litvin ◽  
Venkatraman Gopalan
Keyword(s):  
Magnetic Structure ◽  
Structure Determination ◽  
Time Reversal ◽  
Time Reversal Symmetry ◽  
Space Group ◽  
Space Groups ◽  
Magnetic Structures ◽  
Recent Introduction ◽  
Symmetry Constraints

This work follows from the recent introduction of the rotation-reversal operation intended to be analogous to the time-reversal operation used to describe the symmetry of magnetic structures. As a second independent antisymmetry operation, this operation "doubles" the antisymmetry of the magnetic space groups, hence the term double antisymmetry. Supposing the consideration of both rotation-reversal and time-reversal symmetry, it was found that there are 17,803 types of symmetry that a crystal could exhibit; the 1,651 magnetic space group types being a subset of these, just as the 230 crystallographic space group types are a subset of the magnetic space group types. In addition to discussing the methods applied to determine these types, describing their properties, and listing their symmetry diagrams (available online), the implications for symmetry constraints in magnetic structure determination will be explored.

Ising Model Simulation Of Magnetic Structures IN A Zn-Mg-Ho Structure Model

1998 ◽  
Vol 553 ◽  
Author(s):  
S. Matsuo ◽  
T. Ishimasa ◽  
H. Nakano
Keyword(s):  
Scattering Amplitudes ◽  
Magnetic Structure ◽  
Long Range ◽  
Low Temperatures ◽  
Model Simulation ◽  
Structure Model ◽  
Patterson Function ◽  
Magnetic Structures ◽  
Shortest Distance ◽  
Diffraction Patterns

AbstractSimulated annealing calculations were performed for Ising spins on Ho sites under Ruderman-Kittel-Kasuya-Yosida-like alternating exchange interactions for an icosahedral Zn-Mg-Ho structure model with intent to investigate the magnetic structures at low temperatures. Magnetic structures were analyzed by means of a Patterson function and diffraction patterns arising from spin-dependent scattering amplitudes. The diffraction patterns from the magnetic structure consist of spots at low temperatures in the case of an antiferromagnetic interaction for the shortest distance (3.37 Å) and a ferromagnetic interaction for the second shortest distance (5.46 Å). The Patterson maps indicate a long-range antiferromagnetic correlation. These facts mean that a long-range ordered magnetic structure is realized at low temperatures. The contrast of the diffraction patterns is different from the patterns arising from the spin-independent scattering amplitudes from the Ho sites. A reversed sign interaction, ferromagnetic for the shortest distance and antiferromagnetic for the second shortest distance, results in broad intensity minima in the magnetic diffraction at the positions of strong spots in the spin-independent diffraction by lattice sites. It corresponds to the degradation of the long-range correlation.

scholarly journals Vibronic interaction as main reason of magnetic ordering in insulating manganites R1–xAxMnO3

2018 ◽  
Vol 185 ◽  
pp. 06005
Author(s):  
Liudmila Gonchar ◽  
Anatoliy Nikiforov
Keyword(s):  
Crystal Structure ◽  
Magnetic Structure ◽  
Magnetic Ordering ◽  
Vibronic Interaction ◽  
Magnetic Structures ◽  
Experimental Crystal ◽  
Experimental Crystal Structure

The model of orbitally dependent magnetic structure of charge ordered insulated manganites is proposed. The model is semi-phenomenological. It allows using a few parameters to describe possible magnetic structures of compounds. The experimental crystal structure of compounds also could be taken into account. The compounds LaMnO3, La1/2Ca1/2MnO3, La1/3Ca2/3MnO3, BiMnO3 are considered.

Magnetic Structures of the Intermediate Corona

1994 ◽  
Vol 144 ◽  
pp. 55-59
Author(s):  
S. Koutchmy ◽  
M. M. Molodensky ◽  
V. Koutvitsky ◽  
L. S. Solov’ev
Keyword(s):  
Active Region ◽  
Model Calculation ◽  
Magnetic Structure ◽  
Current Distribution ◽  
Ad Hoc ◽  
Rigid Rotation ◽  
Geometrical Parameters ◽  
Magnetic Structures ◽  
Fine Structures

AbstractThe fine structures of the corona are analized using SXR and WL eclipse pictures. The measurement of the finest features observed at the CFHT on July 11, 1991 is discussed. We call the attention to the 3D aspect of the magnetic structure which can be apprehended and analysed assuming the plasma is concentrated in thin curved sheets observed on eclipse WL pictures. More geometrical parameters can be deduced from the stereo-view based on the hypotheses of a rigid rotation. A preliminary 2.5D model calculation is put forward to explain the active region coronal rays. It is based on the assumption of ad hoc chromospheric current distribution and analytic calculations.

Studies of magnetic structure of written bits using Lorentz microscopy

1989 ◽  
Vol 47 ◽  
pp. 566-567
Author(s):  
T.A. Nguyen ◽  
P.S. Alexopoulos ◽  
S.E. Lambert ◽  
I.L. Sanders ◽  
C. Hwang
Keyword(s):  
Magnetic Structure ◽  
Magnetic Layer ◽  
Information Storage ◽  
Detailed Knowledge ◽  
Magnetic Media ◽  
Lorentz Microscopy ◽  
Magnetic Structures ◽  
Transition Zones ◽  
Size Limits ◽  
Fringing Fields

Understanding the fundamental size limits of magnetic bits for high density information storage requires detailed knowledge of the magnetic structure of the written bits. Bit definition, fringing fields and magnetic structures at and between transition zones are important information for the design of future magnetic media. Using Lorentz microscopy, we have investigated these parameters in Co-alloy thin films as a function of recording density (200, 600 and 1000 fc/mm) on discrete tracks of widths from 0.6 to 10 μm.The magnetic media consist of a Co-alloy and an underlayer prepared by sputtering onto a sputter-cleaned Si disk. The magnetic parameters for the magnetic layer are: coercive field Hc = 950 Oe, remanent magnetization Mr = 533 emu/cm3 and media thickness d = 400 Å. The discrete tracks were formed on the surface of the disk by sputter-etching through a photoresist mask to remove media between the tracks. This permits the recording characteristics of tracks as narrow as 0.6 μm to be investigated using heads of conventional width.

scholarly journals First-principles investigations of the electronic and magnetic structures and the bonding properties of uranium nitride fluoride (UNF)

2017 ◽  
Vol 72 (10) ◽  
pp. 725-730
Author(s):  
Samir F. Matar
Keyword(s):  
Magnetic Structure ◽  
Density Functional ◽  
Geometry Optimization ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Magnetic Structures ◽  
Overlap Population ◽  
Bonding Properties ◽  
Uranium Nitride ◽  
Structure Investigations

AbstractBased on geometry optimization and magnetic structure investigations within density functional theory, a unique uranium nitride fluoride, isoelectronic with UO2, is shown to present peculiar differentiated physical properties. These specificities versus the oxide are related to the mixed anionic substructure and the layered-like tetragonal structure characterized by covalent-like [U2N2]2+ motifs interlayered by ionic-like [F2]2− ones and illustrated herein with electron localization function projections. Particularly, the ionocovalent chemical picture shows, based on overlap population analyses, stronger U–N bonding versus U–F and d(U–N)<d(U–F) distances. Further generalized gradient approximation+U calculations provide the ground state magnetic structure as insulating antiferromagnet with ±2 μB magnetization per magnetic sub-cell and ~2 eV band gap.

Nuclear and Magnetic Structures of K2NiF4-type Iron(III) Oxide Halides

2002 ◽  
Vol 755 ◽  
Author(s):  
Andrew L. Hector ◽  
Alexander I. MacDonald ◽  
Daniel J. Price ◽  
Mark T. Weller
Keyword(s):  
Magnetic Structure ◽  
Magnetic Ordering ◽  
Magnetic Structures ◽  
Antiferromagnetic Ordering ◽  
Ising Antiferromagnet ◽  
Layer Stacking

ABSTRACTK2NiF4-type iron(III) oxides show a very common form of magnetic ordering, XY antiferromagnetic ordering within the layers combined with layer stacking based on alignment of spins in alternate layers. The Ising antiferromagnet Ca2MnO4 has been reported to have a doubled c-axis (ca 24Å) in the magnetic structure and we have found a similar stacking in the XY antiferromagnet Sr2FeO3F. We show here that this unusual c-axis doubling is related to the exposure of the material to air and suggest that in both Sr2FeO3F and Ca2MnO4 it may be related to the occupation of interstitial sites.

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