The Texture and Structure of the Melt-Spun Co2MnAl-Type Heusler Alloy

The structure of the Co2MnAl-type Heusler alloy in the form of a melt-spun ribbon was studied by electron microscopy, electron back-scattered diffraction (EBSD), and X-ray diffraction. The melt-spun ribbon consists of a homogeneous single-phase disordered Heusler alloy at the wheel side of the ribbon and an inhomogeneous single-phase alloy, formed by cellular or dendritic growth, at the free surface of the ribbon. Cellular growth causes the formation of an inhomogeneous distribution of the elemental constituents, with a higher Co and Al concentration in the centre of the cells or dendritic arms and a higher concentration of Mn at the cell boundaries. The EBSD analysis shows that the columnar crystals grow in the <111> crystal direction and are declined by about 10° against the direction of the spinning.

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Improvement of the Magnetic Properties of Nanocrystalline Nd12.3(FeZrNbCu)81.7B6.0Alloys with Dy Substitutions

Journal of Nanomaterials ◽

10.1155/2015/346238 ◽

2015 ◽

Vol 2015 ◽

pp. 1-7

Author(s):

Weiwei Yang ◽

Leichen Guo ◽

Zhimeng Guo ◽

Guangle Dong ◽

Yanli Sui ◽

...

Keyword(s):

Magnetic Properties ◽

Exchange Coupling ◽

Single Phase ◽

X Ray Diffraction ◽

Material Microstructure ◽

X Ray ◽

Maximum Value ◽

Transmission Electron ◽

Melt Spun ◽

Melt Spun Ribbons

Nd12.3−xDyxFe81.7Zr0.8Nb0.8Cu0.4B6.0 (x=0–2.5)ribbons have been prepared by melt-spun at 30 m/s and subsequent annealing. The influence of addition of Dy on the crystallization behavior, magnetic properties, and microstructure were investigated. Differential scanning calorimeter (DSC) and X-ray diffraction (XRD) revealed a single-phase material. Microstructure studies using transmission electron microscopy (TEM) had shown a significant microstructure refinement with Dy addition. Wohlfarth’s analysis showed that the exchange coupling interactions increased first with Dy contentxincreasing, reached the maximum value atx=0.5, and then slightly decreased withxfurther increasing. Optimal magnetic properties withJr=1.09 T,Hci=1048 kA/m, andBHmax=169.5 kJ/m3are achieved by annealing the melt-spun ribbons withx=0.5at% at 700°C for 10 min.

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Raman And Fluorescence Spectra Observed in Laser Microprobe Measurements of Several Compositions in the Ln-Ba-Cu-O System

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134995 ◽

1990 ◽

Vol 48 (2) ◽

pp. 278-279

Author(s):

Edgar S. Etz ◽

Thomas D. Schroeder ◽

Winnie Wong-Ng

Keyword(s):

Fluorescence Spectra ◽

Single Phase ◽

X Ray Diffraction ◽

Ceramic Powders ◽

Conventional Solid State Reaction ◽

X Ray ◽

Raman Microprobe ◽

Methods Of Synthesis ◽

Compositional Homogeneity ◽

Processing Techniques

We are investigating by Raman microprobe measurements the superconducting and related phases in the LnBa2Cu3O7-x (for x=0 to 1) system where yttrium has been replaced by several of the lanthanide (Ln = Nd,Sm,Eu,Ho,Er) elements. The aim is to relate the observed optical spectra (Raman and fluorescence) to the compositional and structural properties of these solids as part of comprehensive materials characterization. The results are correlated with the methods of synthesis, the processing techniques of these materials, and their superconducting properties. Of relevance is the substitutional chemistry of these isostructural systems, the differences in the spectra, and their microanalytical usefulness for the detection of impurity phases, and the assessment of compositional homogeneity. The Raman spectra of most of these compounds are well understood from accounts in the literature.The materials examined here are mostly ceramic powders prepared by conventional solid state reaction techniques. The bulk samples are of nominally single-phase composition as determined by x-ray diffraction.

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Observation of pseudo 10-fold symmetry in the ordered iron-zinc delta phase

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100120588 ◽

1992 ◽

Vol 50 (1) ◽

pp. 36-37

Author(s):

L. A. Giannuzzi ◽

A. S. Ramani ◽

P. R. Howell ◽

H. W. Pickering ◽

W. R. Bitler

Keyword(s):

Single Phase ◽

X Ray Diffraction ◽

Rich Region ◽

Average Cell ◽

X Ray ◽

Delta Phase ◽

Cell Dimensions ◽

Δ Phase ◽

Morphological Differences ◽

Concentration Discontinuity

The δ phase is a Zn-rich intermetallic, having a composition range of ∼ 86.5 - 92.0 atomic percent Zn, and is stable up to 665°C. The stoichiometry of the δ phase has been reported as FeZn7 and FeZn10 The deviation in stoichiometry can be attributed to variations in alloy composition used by each investigator. The structure of the δ phase, as determined by powder x-ray diffraction, is hexagonal (P63mc or P63/mmc) with cell dimensions a = 1.28 nm, c = 5.76 nm, and 555±8 atoms per unit cell. Later work suggested that the layer produced by hot-dip galvanizing should be considered as two distinct phases which are characterized by their morphological differences, namely: the iron-rich region with a compact appearance (δk) and the zinc-rich region with a columnar or palisade microstructure (δp). The sub-division of the δ phase was also based on differences in diffusion behavior, and a concentration discontinuity across the δp/δk boundary. However, work utilizing Weisenberg photographs on δ single crystals reported that the variation in lattice parameters with composition was small and hence, structurally, the δk phase and the δp phase were the same and should be thought of as a single phase, δ. Bastin et al. determined the average cell dimensions to be a = 1.28 nm and c = 5.71 nm, and suggested that perhaps some kind of ordering process, which would not be observed by x-ray diffraction, may be responsible for the morphological differences within the δ phase.

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Thickness Dependence of Degree of B2 Order of Polycrystalline Co 2(Mn 0.6Fe 0.4)Ge Heusler Alloy Films Measured by Anomalous X-Ray Diffraction and its Impacts on Current-Perpendicular-To-Plane Giant Magnetoresistance Properties

SSRN Electronic Journal ◽

10.2139/ssrn.3656137 ◽

2020 ◽

Author(s):

Tomoya Nakatani ◽

Sai Krishna Narayananellore ◽

Loku Singgappulige Rosantha Kumara ◽

Hiroo Tajiri ◽

Yuya Sakuraba ◽

...

Keyword(s):

Heusler Alloy ◽

Giant Magnetoresistance ◽

Thickness Dependence ◽

X Ray Diffraction ◽

Alloy Films ◽

X Ray ◽

Current Perpendicular To Plane

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Preparation of high-entropy carbides by different sintering techniques

Journal of Materials Science ◽

10.1007/s10853-021-06004-y ◽

2021 ◽

Vol 56 (19) ◽

pp. 11237-11247 ◽

Cited By ~ 1

Author(s):

Johannes Pötschke ◽

Manisha Dahal ◽

Mathias Herrmann ◽

Anne Vornberger ◽

Björn Matthey ◽

...

Keyword(s):

Grain Size ◽

Single Phase ◽

X Ray Diffraction ◽

Vacuum Sintering ◽

X Ray ◽

High Entropy ◽

Mean Grain Size ◽

The Mean ◽

Gas Pressure Sintering ◽

Hardness Values

AbstractDense (Hf, Ta, Nb, Ti, V)C- and (Ta, Nb, Ti, V, W)C-based high-entropy carbides (HEC) were produced by three different sintering techniques: gas pressure sintering/sinter–HIP at 1900 °C and 100 bar Ar, vacuum sintering at 2250 °C and 0.001 bar as well as SPS/FAST at 2000 °C and 60 MPa pressure. The relative density varied from 97.9 to 100%, with SPS producing 100% dense samples with both compositions. Grain size measurements showed that the substitution of Hf with W leads to an increase in the mean grain size of 5–10 times the size of the (Hf, Ta, Nb, Ti, V,)C samples. Vacuum-sintered samples showed uniform grain size distribution regardless of composition. EDS mapping revealed the formation of a solid solution with no intermetallic phases or element clustering. X-ray diffraction analysis showed the structure of mostly single-phase cubic high-entropy carbides. Hardness measurements revealed that (Hf, Ta, Nb, Ti, V)C samples possess higher hardness values than (Ta, Nb, Ti, V, W)C samples.

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Influence of Li2CO3 addition on electrical and magnetic properties of Ni0.6Mg0.4Fe2O4

Journal of Advanced Dielectrics ◽

10.1142/s2010135x20500034 ◽

2020 ◽

Vol 10 (03) ◽

pp. 2050003

Author(s):

M. R. Hassan ◽

M. T. Islam ◽

M. N. I. Khan

Keyword(s):

Magnetic Properties ◽

Single Phase ◽

Low Frequency ◽

Solid State Reaction Method ◽

Charge Carriers ◽

X Ray Diffraction ◽

X Ray ◽

Electrical And Magnetic Properties ◽

Frequency Regime ◽

Xrd Patterns

In this research, influence of adding Li2CO3 (at 0%, 2%, 4%, 6%) on electrical and magnetic properties of [Formula: see text][Formula: see text]Fe2O4 (with 60% Ni and 40% Mg) ferrite has been studied. The samples are prepared by solid state reaction method and sintered at 1300∘C for 6[Formula: see text]h. X-ray diffraction (XRD) patterns show the samples belong to single-phase cubic structure without any impurity phase. The magnetic properties (saturation magnetization and coercivity) of the samples have been investigated by VSM and found that the higher concentration of Li2CO3 reduces the hysteresis loss. DC resistivity increases with Li2CO3 contents whereas it decreases initially and then becomes constant at lower value with temperature which indicates that the studied samples are semiconductor. The dielectric dispersion occurs at a low-frequency regime and the loss peaks are formed in a higher frequency regime, which are due to the presence of resonance between applied frequency and hopping frequency of charge carriers. Notably, the loss peaks are shifted to the lower frequency with Li2CO3 additions.

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Impedance Spectroscopy Study of LiTaO3 Powder Synthesized via Sol-Gel Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.545.275 ◽

2012 ◽

Vol 545 ◽

pp. 275-278 ◽

Cited By ~ 1

Author(s):

Lili Widarti Zainuddin ◽

Norlida Kamarulzaman

Keyword(s):

Room Temperature ◽

Single Phase ◽

Sol Gel ◽

Rhombohedral Structure ◽

Spectroscopy Study ◽

X Ray Diffraction ◽

Gel Method ◽

X Ray ◽

Sol Gel Method ◽

Impedance Spectroscopy Study

A ceramics sample of LiTaO3 was prepared using a sol-gel method. The sample is annealed at 750 °C for 48 hours. X-ray diffraction analysis indicate the formation of single phase, rhombohedral structure. An ac impedance study was used to analyse the conductivity of LiTaO3 at room temperature and at various temperatures.

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Colossal Magnetoresistance in Thick La0.7Ca0.3MnO3 Films

MRS Proceedings ◽

10.1557/proc-384-427 ◽

1995 ◽

Vol 384 ◽

Cited By ~ 4

Author(s):

Randolph E. Treece ◽

P. Dorsey ◽

M. Rubinstein ◽

J. M. Byers ◽

J. S. Horwitz ◽

...

Keyword(s):

Colossal Magnetoresistance ◽

Single Phase ◽

Laser Deposition ◽

Orthorhombic Structure ◽

X Ray Diffraction ◽

Post Deposition Annealing ◽

X Ray ◽

Mr Effect ◽

Deposited Films ◽

Post Deposition

ABSTRACTThick films (0.6 and 2.0 μm) of the colossal magnetoresistance (CMR) material, La0.7Ca0.3MnO3 (LCMO), have been grown by pulsed laser deposition (PLD). The films were grown from single-phase LCMO targets in 100 mTorr 02 pressures and the material deposited on (100) LaAlO3 substrates at deposition temperatures of 800°C. The deposited films were characterized by X-ray diffraction (XRD), magnetic field-dependent resistivity, and Rutherford backscattering spectroscopy (RBS). The LCMO films were shown by XRD to adopt an orthorhombic structure. Brief post-deposition annealing led to ~50,000% and ~12,000% MR effect in the 0.6 μm and 2.0 μm films, respectively.

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INVESTIGATIONS ON Sm- AND Nb-SUBSTITUTED PZT CERAMICS

Modern Physics Letters B ◽

10.1142/s0217984906012134 ◽

2006 ◽

Vol 20 (29) ◽

pp. 1879-1882 ◽

Cited By ~ 3

Author(s):

CHANDRA PRAKASH ◽

J. K. JUNEJA

Keyword(s):

Dielectric Constant ◽

Single Phase ◽

Xrd Analysis ◽

Chemical Formula ◽

X Ray Diffraction ◽

Pzt Ceramics ◽

Ceramic Method ◽

X Ray ◽

Niobium Doping ◽

Constant Versus

In the present paper, we report the effect of Samarium substitution and Niobium doping on the properties of a PZT(52:48). The properties studied are: structural, dielectric and ferroelectric. The samples with chemical formula Pb 0.99 Sm 0.01 Zr 0.52 Ti 0.48 O 3 were prepared by solid-state dry ceramic method. Small amount (0.5 wt%) of Nb 2 O 5 was also added. X-ray diffraction (XRD) analysis showed formation of a single phase with tetragonal structure. Dielectric properties were studied as a function of temperature and frequency. Transition temperature, Tc, was determined from dielectric constant versus temperature plot. The material shows well-defined ferroelectric (PE) hysteresis loop.

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