Magnetic and Microstructural Aspects of the Bulk Metallic Glassy Materials Nd60Fe30Al10

2001 ◽  
Vol 674 ◽  
Author(s):  
N. H. Dan ◽  
N. X. Phuc ◽  
V. H. Ky ◽  
N. M. Hong ◽  
N. Chau ◽  
...  
Keyword(s):  
Room Temperature ◽  
Amorphous Material ◽  
Magnetic Hysteresis ◽  
Degree Of Crystallinity ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
Cast Sample ◽  
X Ray ◽  
Glassy Materials ◽  
Ferromagnetic Bulk

ABSTRACTThe ferromagnetic bulk metallic glass (BMG) Nd60Fe30Al10system exhibits extremely large coercivities at low temperature and moderate coercivities near room temperature. The magnetic hardness, as best evidenced by the onset of magnetic irreversibility, was studied in bulk suction-cast and melt-spun alloys with the nominal composition Nd60Fe30Al10. Systematic x-ray diffraction studies of the degree of crystallinity performed as a function of position within the bulk suction-cast samples is found to correlate with the variation in the room-temperature magnetic hysteresis character. X-ray diffraction data clearly shows the presence of both crystallites and amorphous material on the samples' outmost surfaces; the amorphous phase content increases with distance into the cast sample. These results underscore the importance of solidification conditions and attendant nanophase selection, on the resultant magnetic properties of this class of alloys.

scholarly journals Mn-Induced Thermal Stability of L10 Phase in Fept Magnetic Nanoscale Ribbons

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1278
Author(s):  
Alina Daniela Crisan ◽  
Aurel Leca ◽  
Dan Pantelica ◽  
Ioan Dan ◽  
Ovidiu Crisan
Keyword(s):  
Rare Earth ◽  
Single Phase ◽  
Permanent Magnets ◽  
Magnetic Hysteresis ◽  
Ternary Alloys ◽  
Large Temperature ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Operation Conditions

Magnetic nanoscale materials exhibiting the L10 tetragonal phase such as FePt or ternary alloys derived from FePt show most promising magnetic properties as a novel class of rare earth free permanent magnets with high operating temperature. A granular alloy derived from binary FePt with low Pt content and the addition of Mn with the nominal composition Fe57Mn8Pt35 has been synthesized in the shape of melt-spun ribbons and subsequently annealed at 600 °C and 700 °C for promoting the formation of single phase, L10 tetragonal, hard magnetic phase. Proton-induced X-ray emission spectroscopy PIXE has been utilized for checking the compositional effect of Mn addition. Structural properties were analyzed using X-ray diffraction and diffractograms were analyzed using full profile Rietveld-type analysis with MAUD (Materials Analysis Using Diffraction) software. By using temperature-dependent synchrotron X-ray diffraction, the disorder–order phase transformation and the stability of the hard magnetic L10 phase were monitored over a large temperature range (50–800 °C). A large interval of structural stability of the L10 phase was observed and this stability was interpreted in terms of higher ordering of the L10 phase promoted by the Mn addition. It was moreover found that both crystal growth and unit cell expansion are inhibited, up to the highest temperature investigated (800 °C), proving thus that the Mn addition stabilizes the formed L10 structure further. Magnetic hysteresis loops confirmed structural data, revealing a strong coercive field for a sample wherein single phase, hard, magnetic tetragonal L10 exists. These findings open good perspectives for use as nanocomposite, rare earth free magnets, working in extreme operation conditions.

Computer Capability for the Determination of Polymer Crystallinity by X-Ray Diffraction

1985 ◽  
Vol 29 ◽  
pp. 281-290
Author(s):  
Andrew M. Wims ◽  
Mark E. Myers ◽  
Jack L. Johnson ◽  
Julia M. Carter
Keyword(s):  
Room Temperature ◽  
Physical And Mechanical Properties ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Percent Elongation ◽  
X Ray ◽  
Reinforcing Fillers ◽  
Crystalline Domains ◽  
Polymer Crystallinity

The physical and mechanical properties of many industrially important polymers are profoundly influenced by their degree of crystallinity; such properties include flex modulus, tensile strength, percent elongation, and impact strength. Commonly used polymers influenced by their crystallinity level include polyethlene, polypropylene, polyesters, and nylons. Many of these materials are above their glass transition temperature at room temperature and would be useless were it not for their crystalline phase which typically has a melting point far above room temperature. The crystalline ‘ regions (domains) in these materials are frequently very small, typically in the nanometer range in diameter. These crystalline domains act as reinforcing fillers (in somewhat the same manner as carbon black In rubber) and give strength to the polymer.

Room Temperature Ferromagnetism in Powder Form of Sn1-xCrxO2 (x = 0.01, 0.02, 0.03, 0.04 and 0.05) Solid Solution

2009 ◽  
Vol 1201 ◽  
Author(s):  
Kun Xu ◽  
Mitsuru Izumi ◽  
Osami Yanagisawa ◽  
Tetsuya Ida
Keyword(s):  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Lattice Parameter ◽  
Nominal Composition ◽  
Powder Form ◽  
X Ray Diffraction ◽  
Interstitial Position ◽  
X Ray ◽  
Cr Content ◽  
Structural And Magnetic Properties

AbstractStructural and magnetic properties were investigated in the mixed powders of Sn1-xCrxO2 (x = 0.01, 0.02, 0.03, 0.04 and 0.05) in nominal composition. The lattice parameter observed in (110) x-ray diffraction indicates two step changes with increasing Cr content. The occupation of Cr ion at the interstitial position leads to elongation of the lattice parameter for x = 0.01 to x =0.03. Then, the Cr3+ ions are remarkably substituted into the Sn4+ ion site for x = 0.04 to x = 0.05, which results in shortening of the lattice. The lattice parameters for x = 0.01 and 0.02 are larger than x = 0.03 to 0.05. The room temperature ferromagnetism appeared in the sample with x = 0.01 and reaches maximum at the doping rate of x = 0.02; while the magnetization decreases for x > 0.02 was observed. Present study clearly shows the existence of correlation between appearance of ferromagnetism and the structural change.

Synthesis and structure stability of Ba2CuO3+δ under high pressure

2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542024 ◽  
Author(s):  
W. M. Li ◽  
Q. Q. Liu ◽  
Y. Liu ◽  
S. M. Feng ◽  
X. C. Wang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Equation Of State ◽  
Room Temperature ◽  
Text Structure ◽  
Structure Stability ◽  
Nominal Composition ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
X Ray

The [Formula: see text] sample with the nominal composition was synthesized. Powder X-ray diffraction (XRD) experiments confirm that it crystallizes in an orthorhombic structure with space group Immm. The synchrotron powder XRD results suggest that the crystal structure of [Formula: see text] keeps stable under pressure up to 34 GPa at room temperature with nearly isotropic compressibility. The equation of state for [Formula: see text] was obtained. The results offer opportunities to further synthesize and research [Formula: see text] superconductor with tetragonal [Formula: see text] structure.

scholarly journals Effect of Sr-substitution on the structural and magnetoelectric properties of Ni-Zn ferrites

2020 ◽  
Vol 26 (2) ◽  
pp. 1-20
Author(s):  
SC Mazumdar ◽  
AT Trina ◽  
F Alam ◽  
MJ Miah ◽  
MNI Khan
Keyword(s):  
Room Temperature ◽  
Magnetic Hysteresis ◽  
Solid State Reaction Method ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Spinel Type ◽  
Microstructural Investigation ◽  
Xrd Pattern ◽  
X Ray ◽  
Soft Ferrites

Spinel type polycrystalline Ni0.6-xZn0.4SrxFe2O4 (x = 0.0, 0.05, 0.10, 0.15 and 0.20) ferrites are synthesized by solid state reaction method. X-ray diffraction (XRD) pattern reveals the formation of spinel structure with two secondary phases Sr2FeO4 and SrFe12O19 for higher concentration of Sr (0.15 and 0.20). An increase in lattice constant is observed with the increase of Sr content in the lattice. The density of the samples is found to decrease whereas porosity increases with the substitution of Sr2+ ions. Microstructural investigation shows that the grain size increases with the increase of Sr content. Magnetic hysteresis is investigated at room temperature. All the samples exhibit lower coercivity values indicating that the materials belong to the class of soft ferrites. The saturation magnetization is found to decrease with Sr content which is attributed to Néel’s two sub-lattice model of ferrites. The real permeability of the samples remains almost constant up to a certain frequency and then falls rapidly. Improved dielectric constant is observed in the Sr2+ substituted samples. The electrical conduction in these ferrites is explained on the basis of hopping mechanism between the Fe2+ and Fe3+ ions. Bangladesh Journal of Physics, 26(2), 1-20, December 2019

Preparation of Coral-Like α-Fe2O3 Nanostructures and Magnetic Properties

2011 ◽  
Vol 194-196 ◽  
pp. 625-628
Author(s):  
Hong Wang ◽  
Min Gong ◽  
Jing Yu Zhang
Keyword(s):  
Quantum Interference ◽  
Room Temperature ◽  
Magnetic Hysteresis ◽  
Ferromagnetic Behavior ◽  
Average Thickness ◽  
Solvothermal Process ◽  
Superconducting Quantum Interference Device ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Coral-like α-Fe2O3nanostructures modified by surfactant CTAB have been successfully obtained via a solvothermal process by using FeCl36H2O and oxalic acid as the starting materials. The coral-like α-Fe2O3nanostructures with good-crystalline consist of well-aligned α-Fe2O3nanoflakes with an average thickness of about 40 nm growing radially from the center of the nanostructures. The obtained products are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), superconducting quantum interference device magnetometer (SQUID). Magnetic hysteresis measurements indicate that coral-like α-Fe2O3superstructures show a normal ferromagnetic behavior with the remanence and coercivity of 0.2346emu/g and 1862Oe at room temperature. CTAB, the reaction temperature and solvent played an important role in controlling the final morphology of the products.

Preparation and Characterization of Sr, Ba Filled Type-I Ge Clathrate Single Crystals

2007 ◽  
Vol 336-338 ◽  
pp. 896-899 ◽  
Author(s):  
Ke Feng Cai ◽  
L.C. Zhang ◽  
Q. Lei
Keyword(s):  
Single Crystals ◽  
Room Temperature ◽  
Nominal Composition ◽  
Type I ◽  
Vibrational Modes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Optimum Synthesis ◽  
Good Agreement

Sr or Ba filled type-I Ge clathrate single crystals were prepared using high pure elemental Ga, Ge, and Sr or Ba as the starting materials, and Ga as a flux. Powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), differential scanning calorimeter (DSC) were used to characterize the crystals, respectively. The results show that large and well-crystallized single crystals can be prepared under optimum synthesis condition. The composition of the crystals is in good agreement with the nominal composition (M8Ga16Ge30, M=Sr, Ba). Raman spectra of the single crystals were studied at room temperature and several of the Raman active vibrational modes in the crystals have been identified.

Microstructure of radiation-damaged zircon under pressure

2003 ◽  
Vol 36 (4) ◽  
pp. 1006-1012 ◽  
Author(s):  
Susana Ríos ◽  
Tiziana Boffa-Ballaran
Keyword(s):  
Room Temperature ◽  
High Pressures ◽  
Amorphous Matrix ◽  
Amorphous Material ◽  
Uniform Structure ◽  
Simultaneous Increase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Peak Intensity ◽  
Crystalline Domains

Radiation-damaged zircons have been studied at high pressures, up to 7 GPa, by means of single-crystal X-ray diffraction at room temperature. The zircons studied contained high fractions of amorphous material (65 and 85%, respectively). Peak profiles of selected Bragg reflections at room pressure give evidence of the complex microstructure of defective crystalline regions. A differential stress of ∼20 GPa is found between expanded and compressed regions. Two clear stages are observed as a function of pressure: (i) below 3 GPa, diffraction maxima do not show significant changes; (ii) above 3 GPa, a simultaneous increase in peak intensity and decrease in mosaic spread is observed. The effects are attributed to reorientation of crystalline domains within the amorphous matrix. The starting peak profile is recovered after releasing pressure, implying that no significant defect healing is induced in this pressure range, and that all observed effects are reversible. Results are interpreted in terms of the non-uniform structure of amorphous cascades.

scholarly journals Structural characterization and magnetic response of poly(p-xylylene)–MnSb and MnSb films deposited at cryogenic temperature

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
L. N. Oveshnikov ◽  
S. A. Zav’yalov ◽  
I. N. Trunkin ◽  
D. R. Streltsov ◽  
N. K. Chumakov ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Room Temperature ◽  
Qualitative Change ◽  
Layer Growth ◽  
Nominal Composition ◽  
Polymer Content ◽  
X Ray Diffraction ◽  
X Ray ◽  
Complex Correlation ◽  
Spectroscopy Studies

AbstractIn this study, we employed several experimental techniques to investigate structure and magnetic properties of poly(p-xylylene)–MnSb composites synthesized by low-temperature vapor deposition polymerization technique and MnSb films deposited at various temperatures. The presence of MnSb nanocrystallites in the studied films was verified by the results of X-ray diffraction, electron microscopy and Raman spectroscopy studies. The obtained data revealed the formation of Sb-rich sublayer with well-oriented Sb grains near the susbtrate, which seems to act as a buffer for the consequent poly(p-xylylene)–MnSb or MnSb layer growth. Increasing the polymer content results in qualitative change of surface morphology of studied films. At high polymer content the hybrid nanocomposite with MnSb nanoparticles embedded into poly(p-xylylene) matrix is formed. All investigated samples demonstrated detectable ferromagnetic response at room temperature, while the parameters of this response revealed a complex correlation with nominal composition, presented crystal phases and surface morphology of studied films. Estimated values of the Curie temperature of the samples are close to that of bulk MnSb.

scholarly journals Effect of the incorporation of BiFeO3 on the structural, electrical and magnetic properties of the lead-free Bi0.5Na0.5TiO3

2021 ◽  
Vol 8 (5) ◽  
pp. 792-808
Author(s):  
Wolfgang Zúñiga-Mera ◽  
◽  
Sonia Gaona Jurado ◽  
Alejandra Isabel Guerrero Duymovic ◽  
Claudia Fernanda Villaquirán Raigoza ◽  
...  
Keyword(s):  
Room Temperature ◽  
Oxygen Vacancies ◽  
Structural Phase ◽  
Magnetic Hysteresis ◽  
X Ray Diffraction ◽  
Electrical Measurements ◽  
X Ray ◽  
Electrical And Magnetic Properties ◽  
System 1 ◽  
Rhombohedral Symmetry

<abstract> <p>Powders of the system (1–<italic>x</italic>)Bi<sub>0.5</sub>Na<sub>0.5</sub>TiO<sub>3</sub>–<italic>x</italic>BiFeO<sub>3</sub> (<italic>x</italic> = 0, 0.02, 0.08, 0.10) are synthesized by the combustion reaction method. The crystal structure and the particle size of Bi<sub>0.5</sub>Na<sub>0.5</sub>TiO<sub>3</sub> are modified by the incorporation of BiFeO<sub>3</sub>, as can be seen from the infrared spectroscopy and X-ray diffraction results. The inclusion of iron and the increase in the molar percentage of bismuth in the BNT matrix generate new bonds with a different force constant. The structural analysis showed that the addition of BFO to the BNT does not induce any structural phase transition, preserving the rhombohedral symmetry of the Bi<sub>0.5</sub>Na<sub>0.5</sub>TiO<sub>3</sub> system. The electrical measurements show that the incorporation of iron increases the conductivity of the system generated by an increase in the concentration of oxygen vacancies; alternatively, the addition of 10% of BiFeO<sub>3</sub> generates ferrimagnetic behavior reflected in the magnetic hysteresis curves obtained at room temperature.</p> </abstract>

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