scholarly journals Magnetic Phase Separation and Magnetic Moment Alignment in Ordered Alloys FE65Al35−xMx (Mx = Ga, B; x = 0; 5 at.%)

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
E. V. Voronina ◽  
A. K. Arzhnikov ◽  
A. I. Chumakov ◽  
N. I. Chistyakova ◽  
A. G. Ivanova ◽  
...  
Keyword(s):  
Phase Separation ◽  
Ternary Alloy ◽  
Binary Alloy ◽  
Magnetic Measurements ◽  
Density Wave ◽  
Spin Density Wave ◽  
Magnetic Characteristics ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
Ordered Alloys

The structure and the magnetic state of ordered Fe65Al35-xMx (Mx = Ga, B; x = 0; 5 at.%) alloys are investigated using X-ray diffraction, Mössbauer spectroscopy, and magnetic measurements. The behavior of the magnetic characteristics and Mössbauer spectra of the binary alloy Fe65Al35 and the ternary alloy with gallium addition Fe65Al30Ga5 is explained in terms of the phase separation into two magnetic phases: a ferromagnetic one and a spin density wave. It is shown that the addition of boron to the initial binary alloy Fe65Al35 results in the ferromagnetic behavior of the ternary alloy.

scholarly journals Магнитное состояние квазиупорядоченных сплавов Fe-Al с добавками Ga и B: магнитное фазовое расслоение и спиновый порядок

2018 ◽  
Vol 60 (4) ◽  
pp. 726
Author(s):  
Е.В. Воронина ◽  
А.Г. Иванова ◽  
А.К. Аржников ◽  
А.И. Чумаков ◽  
Н.И. Чистякова ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Single Phase ◽  
Magnetic State ◽  
Magnetic Phase ◽  
Density Wave ◽  
Spin Density Wave ◽  
Magnetic Characteristics ◽  
Magnetic Phases ◽  
Boron Doped ◽  
Ordered Alloys

AbstractResults of structural, magnetic, and Mössbauer studies of quasi ordered alloys Fe_65Al_35 − x M_ x ( M _ x = Ga, B; x = 0, 5 at %) are presented. The magnetic state of examined structurally–single-phase alloys at low temperatures is interpreted from the viewpoint of magnetic phase separation. An explanation is proposed for the observed behavior of magnetic characteristics of Fe_65Al_35 and Fe_65Al_30Ga_5 in the framework of the model of two magnetic phases, a ferromagnetic-type one and a spin density wave. The boron-doped alloy Fe_65Al_30B_5 is shown to demonstrate behavior that is typical of materials with the ferromagnetic type of ordering.

Phase Separation in a Spin Density Wave State of Twisted Bilayer Graphene

JETP Letters ◽  
2020 ◽  
Vol 112 (10) ◽  
pp. 651-656
Author(s):  
A. O. Sboychakov ◽  
A. V. Rozhkov ◽  
K. I. Kugel ◽  
A. L. Rakhmanov
Keyword(s):  
Phase Separation ◽  
Spin Density ◽  
Density Wave ◽  
Spin Density Wave ◽  
Bilayer Graphene ◽  
Wave State ◽  
Twisted Bilayer Graphene

scholarly journals Structural investigations in BaFe2 − xRuxAs2as a function of Ru and temperature

2015 ◽  
Vol 71 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Shilpam Sharma ◽  
A. Bharathi ◽  
K. Vinod ◽  
C. S. Sundar ◽  
V. Srihari ◽  
...  
Keyword(s):  
Bond Length ◽  
Structural Parameters ◽  
Magnetic Transition ◽  
Density Wave ◽  
Spin Density Wave ◽  
Geometric Optimization ◽  
X Ray Diffraction ◽  
Structural Investigations ◽  
Rietveld Refinements ◽  
Bond Angles

We present the results of synchrotron X-ray diffraction (XRD) measurements on powdered single-crystal samples of BaFe2 − xRuxAs2, as a function of Ru content, and as a function of temperature, across the spin-density wave transition in BaFe1.9Ru0.1As2. The Rietveld refinements reveal that with Ru substitution, while thea-axis increases, thec-axis decreases. In addition, the variation of positional coordinates of As (zAs), the Fe—As bond length and the As—Fe—As bond angles have also been determined. In the sample withx= 0.1, temperature-dependent XRD measurements indicate that the orthorhombicity shows the characteristic increase with a decrease in temperature, below the magnetic transition. It is seen that thec-axis, the As—Fe—As bond angles, Fe—As bond length and positional coordinates of the As show definite anomalies close to the structural transition. The observed anomalies in structural parameters are analysed in conjunction with restricted geometric optimization of the structure usingab initioelectronic structure calculations.

STRUCTURE AND MAGNETIC PROPERTIES OF Co-DOPED SnO2 NANOWIRES

2011 ◽  
Vol 10 (04n05) ◽  
pp. 967-971 ◽  
Author(s):  
U. K. GOUTAM ◽  
SHASHWATI SEN ◽  
JAGANNATH ◽  
A. K. SINGH ◽  
R. MUKUND ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Magnetic Measurements ◽  
Ferromagnetic Behavior ◽  
Tubular Furnace ◽  
X Ray Diffraction ◽  
X Ray ◽  
Co Doping ◽  
Sno2 Nanowires ◽  
Tin Metal ◽  
Co Doped

Co -doped SnO2 nanowires were grown by thermal evaporation of a mixture of Tin metal powder and CoCl2 · 6H2O in a tubular furnace. The growth occurs by vapor–solid growth mechanism. Nanowires grew along the sidewall of the alumina boat placed in the tubular furnace and the diameter of these nanowires (as was evident from scanning electron microscopy), was found to be in the range of 50 nm to 200 nm. Co was successfully doped in SnO2 lattice as revealed by X-ray diffraction data and was found to be in Co2+ state in the nanowires as detected by X-ray Photoelectron Spectroscopy measurements. Room temperature magnetic measurements, carried out using Vibrating Sample Magnetometer, indicated ferromagnetic behavior of the nanowires indicating their potential for spintronics applications. With increasing Co doping (upto 1%), the lattice parameters of SnO2 decreased and the saturation magnetization increased, suggesting a strong structure-magnetic property relationship.

scholarly journals Spin density wave dislocation in chromium probed by coherent X-ray diffraction

2009 ◽  
Vol 70 (3) ◽  
pp. 317-325 ◽  
Author(s):  
V. L.R. Jacques ◽  
D. Le Bolloc’h ◽  
S. Ravy ◽  
C. Giles ◽  
F. Livet ◽  
...  
Keyword(s):  
Spin Density ◽  
Density Wave ◽  
Spin Density Wave ◽  
X Ray Diffraction ◽  
X Ray

XPS and Magnetization Measurements Study of CrMn Nanoparticles

2001 ◽  
Vol 704 ◽  
Author(s):  
Wathiq Abdul-Razzaq ◽  
Unchul Lee
Keyword(s):  
Complex System ◽  
Spin Glass ◽  
Density Wave ◽  
Spin Density Wave ◽  
Zero Field ◽  
X Ray Diffraction ◽  
X Ray ◽  
Weak Fields ◽  
Zero Field Cooling ◽  
Spin Glass System

AbstractCr1-xMnx (x < 6.3 %) alloy in the bulk form is an interesting complex system that behaves in many but not all respects like a spin-glass system. In this study, 14 nm-size CrMn nanoparticles with 5% Mn, were synthesized by ball milling of Cr and Mn particles in Ar atmosphere. After 50 hours of milling, the x-ray diffraction pattern indicated alloying of the two metals Cr and Mn. However XPS data indicated the formation of MnO2 and Cr2O3oxides on the surface of the chromium core in the nanoparticle. These oxides on the surface, like the Cr core, are antiferromagnets. Magnetization (M) measurement at 200 G as a function of temperature (T), after zero-field-cooling, showed that M increased as T increased from 5 K all the way to 330 K, beyond the Neel temperatures of the Cr and the oxides. Even though the magnetization value is in the range of a typical antiferromagnet at all temperatures from 5 to 330 K, the shape of M versus T curve is neither that of an antiferromagnet nor of a spin-glass. It appears that the behavior of the magnetization curve is due to the frustration of the spins by weak fields associated with spin-density-wave and by the existence of the oxides. This frustration should be different from the frustration of the spins due to the ferromagnetic-antiferromagnetic competition in spin-glass systems.

scholarly journals Structural and magnetic properties of gadolinium modified BiFeO3

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
L.M. Ramírez Guzmán ◽  
A.F. Cruz Pacheco ◽  
J.A. Gómez Cuaspud ◽  
C.A. Parra Vargas
Keyword(s):  
Photoelectron Spectroscopy ◽  
Morphological Analysis ◽  
Solid State Reaction Method ◽  
Magnetic Characteristics ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
X Ray ◽  
Group A ◽  
Interconnected Structure

Abstract This paper reports the synthesis and characterization of the Bi0:94Gd0:06FeO3 sample obtained by solid state reaction method. The structural and morphological analysis was performed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Rietveld refinement analysis, confirming the obtaining of a rhombohedral crystalline phase and R3c space group (a = b = 5.577 Å and c = 13.847 Å), with an interconnected structure. Studies by X-ray photoelectron spectroscopy (XPS) revealed trivalent oxidation states of Bi, Fe and Gd ions. The synthesized sample exhibited a non-linear M–H loop indicating a weak ferromagnetic behavior with a remnant magnetization of 6.34 emu˙mol−1 and a coercive field of 295 Oe. The obtained structural and magnetic characteristics make these materials of great interest as multiferroic components.

Structural and magnetic properties of pure and cobalt doped Gallium Nitride nanocrystals

2010 ◽  
Vol 1257 ◽  
Author(s):  
Vottikondala Ganesh ◽  
Suresh Sundaram ◽  
Krishnan Baskar
Keyword(s):  
Magnetic Properties ◽  
Gallium Nitride ◽  
Magnetic Measurements ◽  
Raw Materials ◽  
Ferromagnetic Behavior ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural And Magnetic Properties ◽  
Co Doped

AbstractIn the present study pure and doped gallium nitride (GaN) nanocrystals were synthesized using gallium trichloride (GaCl3), ethylene diamine tetra acetic acid (EDTA) and cobalt chloride as raw materials at a temperature of 900 °C in ammonia (NH3) atmosphere. The XRD spectrum for pure and cobalt doped GaN nanocrystals shows the formation of single phase wurtzite structure. No impurity phases were observed in the X-ray diffraction pattern for 5% Co doped sample whereas secondary phases were observed when the doping concentration exceeds 5 %. Shift in X-ray diffraction peaks were observed in Co doped samples towards lower angle side compared to pure GaN, it confirms that the Co atoms introduces in to the GaN lattice. Transmission electron microscopy images were taken for pure and Co doped GaN. Hexagonal morphology was observed in pure GaN samples. The average size of the particle was found to be ˜20 nm for pure and Co doped GaN. The magnetic measurements were carried out for the Co (5% & 10%) doped samples both at 10K and 300K. Clear hysteresis loop in the magnetization curve suggest the presence of ferromagnetic behavior in cobalt doped GaN. Temperature dependent magnetization (M-T) measurements were also carried out for doped samples using Super Conducting Quantum Interface Device (SQUID) from 10K to 300K The results have been discussed and correlated to structural and magnetic properties of the materials.

Synthesis and Characterization of Bimetallic Pd-Co Nano Magnetic Materials in Mesoporous Silica

2008 ◽  
Vol 1118 ◽  
Author(s):  
Balaji Tatineni ◽  
Dhananjay Kumar ◽  
Joslyn Perkins ◽  
Sergey Yarmolenko ◽  
Debasish Kuila
Keyword(s):  
Mesoporous Silica ◽  
Magnetic Measurements ◽  
Ammonium Bromide ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
One Pot ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Cetyl Trimethyl Ammonium ◽  
Co Nanoparticles

ABSTRACTAn one-pot procedure was developed for the synthesis of mesoporous silica containing bimetallic PdCo using Pd(NO3)2 and CoCl2, and cetyl trimethyl ammonium bromide (CTAB) as the templating agent, and tetramethoxy silane (TMOS) as the precursor. The materials were characterized using high resolution scanning transmission electron microscopy (HRSTEM), elemental analysis, X-ray diffraction (XRD), and magnetic measurements. The data indicate that the bimetallic Pd-Co nanoparticles are uniformly distributed on the inner pore walls of silica. The magnetic measurements of reduced Pd-Co nanoparticles (4-5 nm) in mesoporous silica reveal a typical ferromagnetic behavior up to 20 K and exhibit superparamagnetic properties above 30 K.

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