Strain induced magnetic anisotropy and 3d 7 ions effect in CoFe 2 O 4 nanoplatelets
TL;DR: In this article, the compressive microstrain of 0.024 and 0.016 was estimated for CoFe2O4 samples H120 and H180 respectively using Williamson-Hall plot analysis assuming uniform deformation model.
About: This article is published in Superlattices and Microstructures.The article was published on 2017-11-01. It has received 25 citations till now. The article focuses on the topics: Magnetic anisotropy & Cubic crystal system.
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TL;DR: In this paper, the loading of trace Au on CoFe2O4 surface by electrochemical method has been shown to improve the oxygen evolution reaction (OER) activity, decreasing the overpotential of 374mV at 10.5m V at 10m cm−2 to 312mV and showing a small Tafel slope of 35mV in 1m KOH.
35 citations
TL;DR: In this article, a singe phase bismuth ferrite doped by yttrium (Bi1−xYxFeO3, x = 0, 0.05, 1, 0., 0.15, 1.2 and 0.25) was synthesized by solid-state reaction followed by sintering.
31 citations
TL;DR: The dielectric properties of pure and yttrium-doped PbS nanoparticles synthesized by the coprecipitation chemical synthesis route have been studied by several characterizations as discussed by the authors.
Abstract: The dielectric properties of pure and yttrium-doped PbS nanoparticles synthesized by the coprecipitation chemical synthesis route have been studied by several characterizations. X-ray diffraction patterns of samples were employed to estimate the crystallite sizes and intrinsic microstrains using Williamson–Hall (W–H) plot analysis. The crystallite size and intrinsic macrostrain values were evaluated in the range of 13.7–15.9 nm and 1.09 × 10–3–1.72 × 10–3, respectively, using W–H plots. The formation of nanoparticles, nanoflakes, sponge, and nanosheets were seen via scanning electron microscope (SEM). Energy dispersive spectroscopy (EDS) of 5.0 wt% confirms the Y: PbS sample elements' chemical composition and stoichiometry. The optical band gaps increase in the range of (0.93–1.17 eV) with an increase in the dislocation density. The higher values of dielectric constant (23.6–28.0), dielectric loss (37.6–176.8), loss tangent (2.7–8.6), and electrical conductivity [ 10.2 to ( 11.7) S/m] have been reported at the lower frequency. The highest electrical conductivity values were obtained in the range of [ 4.71 to ( 4.81) S/m] for as-prepared samples. The greater capacitance and impedance values were found at 3 kHz and decrease with increasing the frequency up to 10 MHz. The current–voltage characteristic curves of undoped and Y: PbS NPs were performed under biased voltage. The space charge current density was noticed in the range of (8.7 × 10–4–4.2 × 10–4 amp/cm2) at 1.0, 2.5, and 5.0 wt% of Y: PbS samples. The enhancement in the optical band gap and dielectric and electric properties on yttrium doping in PbS compared to pristine PbS NPs makes them suitable for optoelectronic applications.
25 citations
Cites background from "Strain induced magnetic anisotropy ..."
...As the crystallite size D[ [ a, the lattice microstrain and lattice parameter variation follows the grain size dependence rule close to the ratio ð1=DÞ [35]....
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TL;DR: MFe2O4 spinel ferrites (M = Co, Mn, Ni, Zn) were synthesized through a low-temperature aqueous route combining co-precipitation of oxalates and hydrothermal treatment at 135 °C as discussed by the authors.
25 citations
TL;DR: Boron nitride nanosheet (BNNS) decorated with cobalt ferrite nanoparticle (CFN) was prepared via a simple hydrothermal route and was well characterized.
Abstract: Boron nitride nanosheet (BNNS) decorated with cobalt ferrite nanoparticle (CFN) to afford CFN-BNNS nanohybrid was prepared via a simple hydrothermal route and was well characterized. Subsequently, ...
21 citations
References
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Book•
01 Jan 1960
TL;DR: In this paper, the authors discuss the nature and properties of liquid interfaces, including the formation of a new phase, nucleation and crystal growth, and the contact angle of surfaces of solids.
Abstract: Capillarity. The Nature and Thermodynamics of Liquid Interfaces. Surface Films on Liquid Substrates. Electrical Aspects of Surface Chemistry. Long--Range Forces. Surfaces of Solids. Surfaces of Solids: Microscopy and Spectroscopy. The Formation of a New Phase--Nucleation and Crystal Growth. The Solid--Liquid Interface--Contact Angle. The Solid--Liquid Interface--Adsorption from Solution. Frication, Lubrication, and Adhesion. Wetting, Flotation, and Detergency. Emulsions, Foams, and Aerosols. Macromolecular Surface Films, Charged Films, and Langmuir--Blodgett Layers. The Solid--Gas Interface--General Considerations. Adsorption of Gases and Vapors on Solids. Chemisorption and Catalysis. Index.
10,790 citations
Book•
01 Jun 1972
TL;DR: In this paper, the authors present materials at the practical rather than theoretical level, allowing for a physical, quantitative, measurement-based understanding of magnetism among readers, be they professional engineers or graduate-level students.
Abstract: Introduction to Magnetic Materials, 2nd Edition covers the basics of magnetic quantities, magnetic devices, and materials used in practice. While retaining much of the original, this revision now covers SQUID and alternating gradient magnetometers, magnetic force microscope, Kerr effect, amorphous alloys, rare-earth magnets, SI Units alongside cgs units, and other up-to-date topics. In addition, the authors have added an entirely new chapter on information materials. The text presents materials at the practical rather than theoretical level, allowing for a physical, quantitative, measurement-based understanding of magnetism among readers, be they professional engineers or graduate-level students.
6,573 citations
04 May 1948-Philosophical transactions - Royal Society. Mathematical, physical and engineering sciences
TL;DR: In this paper, the effect of shape anisotropy on magnetization curves was studied for the case of ellipsoidal spheroids of revolution (e.g., ellipses of revolution).
Abstract: The Becker-Kersten treatment of domain boundary movements is widely applicable in the interpretation of magnetization curves, but it does not account satisfactorily for the higher coercivities obtained, for example, in permanent magnet alloys. It is suggested that in many ferromagnetic materials there may occur ‘particles’ (this term including atomic segregates or ‘islands’ in alloys), distinct in magnetic character from the general matrix, and below the critical size, depending on shape, for which domain boundary formation is energetically possible. For such single-domain particles, change of magnetization can take place only by rotation of the magnetization vector, I O . As the field changes continuously, the resolved magnetization, I H , may change discontinuously at critical values, H O , of the field. The character of the magnetization curves depends on the degree of magnetic anisotropy of the particle, and on the orientation of ‘easy axes’ with respect to the field. The magnetic anisotropy may arise from the shape of the particle, from magneto-crystalline effects, and from strain. A detailed quantitative treatment is given of the effect of shape anisotropy when the particles have the form of ellipsoids of revolution (§§ 2, 3, 4), and a less detailed treatment for the general ellipsoidal form (§ 5). For the first it is convenient to use the non-dimensional parameter such that h = H /(| N a - N b |) I O , N a and N b being the demagnetization coefficients along the polar and equatorial axes. The results are presented in tables and diagrams giving the variation with h of I H / I O . For the special limiting form of the oblate spheroid there is no hysteresis. For the prolate spheroid, as the orientation angle, θ , varies from 0 to 90°, the cyclic magnetization curves change from a rectangular form with | h O | = 1, to a linear non-hysteretic form, with an interesting sequence of intermediate forms. Exact expressions are obtained for the dependence of h θ on θ , and curves for random distribution are computed. All the numerical results are applicable when the anisotropy is due to longitudinal stress, when h = HI 0 /3λδ, where λ is the saturation magnetostriction coefficient, and δ the stress. The results also apply to magneto-crystalline anisotropy in the important and representative case in which there is a unique axis of easy magnetization as for hexagonal cobalt. Estimates are made of the magnitude of the effect of the various types of anisotropy. For iron the maximum coercivities, for the most favourable orientation, due to the magneto-crystalline and strain effects are about 400 and 600 respectively. These values are exceeded by those due to the shape effect in prolate spheroids if the dimensional ratio, m , is greater than 1·1; for m = 10, the corresponding value would be about 10,000 (§7). A fairly precise estimate is made of the lower limit for the equatorial diameter of a particle in the form of a prolate spheroid below which boundary formation cannot occur. As m varies from 1 (the sphere) to 10, this varies from 1·5 to 6·1 x 10 -6 for iron, and from 6·2 to 25 x 10 -6 for nickel (§ 6). A discussion is given (§ 7) of the application of these results to ( a ) non-ferromagnetic metals and alloys containing ferromagnetic ‘impurities’, ( b ) powder magnets, ( e ) high coeravity alloys of the dispersion hardening type. In connexion with ( c ) the possible bearing on the effects of cooling in a magnetic field is indicated.
4,382 citations
Book•
01 Jan 1962
TL;DR: This chapter introduces the theory of transition metal chemistry and its applications in ligand field theory and discusses the role of uranium in this theory.
Abstract: INTRODUCTION TO LIGAND FIELD THEORY BY CARL J. INTRODUCTION TO LIGAND FIELD THEORY VIDEO DAILYMOTION. INTRODUCTION TRANSITION METAL CHEMISTRY LIGAND FIELD THEORY. LIGAND FIELD THEORY WWWCHEM UWIMONA EDU JM. CHAPTER 23 INTRODUCTION TO THE TRANSITION ELEMENTS LIGAND. WILEY LIGAND FIELD THEORY AND ITS APPLICATIONS BRIAN N. CARL J BALLHAUSEN INTRODUCTION TO LIGAND FIELD THEORY. INTRODUCTION TO LIGAND FIELD THEORY
1,890 citations
Book•
09 Jun 2013
TL;DR: In this article, X-Rays and Diffraction Lattices and Crystal Structures and Hexagonal Structures are used for X-Ray Diffraction Experimental Modules: Crystal structure determination, I: Cubic Structures Crystal Structure Determination, II: Hexagonal structures Precise Lattice Parameter Measurements Phase Diagram Determination Detection of Long-Range Ordering Determination of Crystallite Size and Lattite Strain Quantitative Analysis of Powder Mixtures Identification of an Unknown Specimen: Appendices: Plane-Spacing Equations and Unit
Abstract: Basics: X-Rays and Diffraction Lattices and Crystal Structures Practical Aspects of X-Ray Diffraction Experimental Modules: Crystal Structure Determination, I: Cubic Structures Crystal Structure Determination, II: Hexagonal Structures Precise Lattice Parameter Measurements Phase Diagram Determination Detection of Long-Range Ordering Determination of Crystallite Size and Lattice Strain Quantitative Analysis of Powder Mixtures Identification of an Unknown Specimen: Appendices: Plane-Spacing Equations and Unit Cell Volumes Quadratic Forms of Miller Indices for the Cubic System Atomic and Ionic Scattering Factors of Some Selected Elements Summary of Structure Factor Calculations Mass Absorption Coefficients mu/rho (cm2/g) and Densities rho (g/cm3) of Some Selected Elements Multiplicity Factors Lorentz-Polarization Factor Physical Constants and Conversion Factors JCPDS-ICDD Card Numbers for Some Common Materials Index
1,594 citations