Showing papers on "Hysteresis published in 1984"
TL;DR: In this paper, the authors discuss the behavior of a liquid partially wetting a solid surface, when the contact angle at equilibrium θ 0 is small, but finite, and show that there may exist two stable positions for the line, obtained by a simple graphic construction.
Abstract: We discuss the behavior of a liquid partially wetting a solid surface, when the contact angle at equilibrium θ0 is small, but finite. The solid is assumed to be either flat, but chemically heterogeneous (this in turn modulating the interfacial tensions), or rough. For weak heterogeneities, we expect no hysteresis, but the contact line becomes wiggly. For stronger heterogeneities, we first discuss the behavior of the contact line in the presence of a single, localized defect, and show that there may exist two stable positions for the line, obtained by a simple graphic construction. Hysteresis shows up when the strength of the defect is above a certain threshold. Extending this to a dilute system of defects, we obtain formulas for the ‘‘advancing’’ and ‘‘receding’’ contact angles θa, θr, in terms of the distribution of defect strength and defect sharpness. These formulas might be tested by controlled contamination of a solid surface.
845 citations
TL;DR: In this article, a mathematical theory of hysteresis in ferromagnetic materials is presented based on existing ideas of domain wall motion and domain rotation, which is shown to occur as a result of impedances to changes of magnetization such as when domain walls are pinned.
Abstract: A mathematical theory of hysteresis in ferromagnetic materials is presented based on existing ideas of domain wall motion and domain rotation. Hysteresis is shown to occur as a result of impedances to changes of magnetization such as when domain walls are pinned, while the mutual interactions of the magnetic moments are shown to be of secondary importance in this respect. An equation for the anhysteretic or ideal magnetization curve is derived based on a mean field approximation and this is shown to be dependent on the mutual interactions of the moments but independent of impedances such as pinning. The introduction of a term which measures the impedance to changes in magnetization leads to a simple differential equation of state for a ferromagnet which exhibits all the features of hysteresis. Some modifications of the simple model are necessary in order to bring the solution closer to the real situation. Results are presented which show all the features of hysteresis such as initial magnetization curve, major hysteresis loops, and minor hysteresis loops in excellent agreement with experimental results.
480 citations
TL;DR: The dependent-domain theory of hysteresis developed here accounts for the effect of the pore-water blockage against air entry while using the similarity hypothesis of the universal model, and seems to agree with observations much better that Model II, which uses the same amount of data for calibration.
Abstract: The dependent-domain theory of hysteresis developed here accounts for the effect of the pore-water blockage against air entry, while using the similarity hypothesis of the universal model (Mualem 1977). The resulting model is simpler and requires fewer data for calibration than previous depe
157 citations
TL;DR: In this article, a general critical-state theory was proposed for calculations of hysteresis in type-II superconductors in parallel applied magnetic fields that vary in both magnitude and direction.
Abstract: A general critical-state theory, including the effects of both flux-line cutting and flux pinning, is proposed for calculations of hysteresis in type-II superconductors in parallel applied magnetic fields that vary in both magnitude and direction. In this theory, if the magnitude of the electrical-current-density component perpendicular to the magnetic induction $\stackrel{\ensuremath{\rightarrow}}{\mathrm{B}}$ exceeds the corresponding critical value ${J}_{c\ensuremath{\perp}}$, depinning occurs, and an electric field component ${E}_{\ensuremath{\perp}}$ perpendicular to $\stackrel{\ensuremath{\rightarrow}}{\mathrm{B}}$ appears; if the magnitude of the current-density component parallel to $\stackrel{\ensuremath{\rightarrow}}{\mathrm{B}}$ exceeds the corresponding critical value ${J}_{c\ensuremath{\parallel}}$, flux-line cutting occurs, and an electric field component ${E}_{\ensuremath{\parallel}}$ parallel to $\stackrel{\ensuremath{\rightarrow}}{\mathrm{B}}$ appears. Model calculations are performed to solve for the electrodynamic response of a slab subjected to a parallel, constant magnetic field whose direction undergoes either continuous rotation or periodic oscillation. The relation of the theory to the pioneering experiments of LeBlanc and co-workers is discussed.
81 citations
80 citations
TL;DR: In this article, the dielectric constant of betaine calcium chloride dihydrate (CH3)3NCH2COO*CaCl2*2H20) is measured at about 20000 near 125 K.
Abstract: Single crystals of betaine calcium chloride dihydrate ((CH3)3NCH2COO*CaCl2*2H20) are grown from aqueous solutions. The dielectric constant shows several distinct anomalies with the highest values of about 20000 near 125 K. Below this temperature complex dielectric hysteresis loops are observed. Their shape strongly depends on temperature, field and frequency. Below 51 K only single loops can be obtained which probably indicate a ferroelectric phase.
73 citations
TL;DR: In this article, disordered Ni-Mn alloys are seen to evolve from a characteristic spinglass behavior, with the magnetic polarizability rapidly increasing, to a magnetic behavior that signifies the onset of ferromagnetic order and the appearance of a spinglass-like phase at lower temperatures.
Abstract: With decreasing Mn concentration near 25 at. %, disordered Ni‐Mn alloys are seen to evolve from a characteristic spin‐glass behavior, with the magnetic polarizability rapidly increasing, to a magnetic behavior that signifies the onset of ferromagnetic order and the appearance of a spin‐glass‐like phase at lower temperatures. Moreover, the latter phase is ‘‘mixed’’ in that its equilibrium state (in the fields applied during cooling) manifests a spontaneous ferromagnetic moment, while its magnetization reversals with field exhibit the unidirectional anisotropy of a spin glass. The unusual magnetic properties of the mixed phase in the zero‐field‐cooled state can be ascribed to a domain structure in which the domains have unidirectional anisotropies of random orientation.
62 citations
TL;DR: In this article, it is suggested that much of the grain size dependence of magnetic behavior in the pseudosingle domain grain size range can be attributed to the increasing difficulty with which walls are nucleated, as particle size decreases.
Abstract: Difficulties in domain wall nucleation have been shown to affect the domain state of the fine magnetic particles in rocks. Particles, large enough to contain a domain wall, remain saturated in remanence and only nucleate a wall when a backfield is applied. In this paper, nucleation is described during hysteresis, stress cycles and cycles through the low temperature anisotropy transition in magnetite. It is suggested that much of the grain size dependence of magnetic behaviour in the pseudosingle domain grain size range can be attributed to the increasing difficulty with which walls are nucleated, as particle size decreases.
61 citations
TL;DR: A method is described whereby, utilising a biocompatible magnetic glass-ceramic material, effective hysteresis heating in living tissue was accomplished and initial experiments showed that a significant heating effect can be obtained in the ceramic-impregnated regions.
Abstract: A method is described whereby, utilising a biocompatible magnetic glass-ceramic material, effective hysteresis heating in living tissue was accomplished. Initial experiments on mice showed that a significant heating effect can be obtained in the ceramic-impregnated regions. An analysis is also given for the projected safe operating field-frequency regime of the hysteresis therapy.
48 citations
TL;DR: In this article, the effect of loading history on the deformation response of a low carbon steel is examined and some results on the determination of the shape and area of stabilized hysteresis loops obtained under cyclic loading are presented.
45 citations
TL;DR: In this paper, the presence of a magnetically soft initial or nucleation layer in RF diode sputtered CoCr films was found to be consistent with curling or buckling.
Abstract: Results are reported which indicate the presence of a magnetically soft initial or nucleation layer in RF diode sputtered CoCr films. As a whole, the films have strong perpendicular anisotropy. However, there appears to be an initial layer some 1000-1500 angstroms thick for 1 micron films and its presence is noted in SEM fracture cross-sections, in-plane hysteresis loops, and in rotational hysteresis torque measurements. This layer seems to reverse by in-plane domain wall motion in spite of the dominant perpendicular curling or buckling reversal of the film as a whole. At small fields, the reversal is clearly by domain wall motion involving only a fraction of the volume while at higher fields the reversal is consistent with curling or buckling and involves almost all of the volume.
TL;DR: In this paper, the surface energy of glass plates was modified by chemisorption of organochlorosilanes and an interesting behavior of the water-air contact angle hysteresis as a function of reagent concentration was observed.
TL;DR: In this paper, a system is described which allows on-line control of uniaxial stress and magnetic field for the investigation of the magnetic properties of materials under stress, and exact algorithms for the demagnetization of samples and for obtaining the anhysteretic or ideal magnetization curve have been devised.
Abstract: A system is described which allows on‐line control of uniaxial stress and magnetic field for the investigation of the magnetic properties of materials under stress. This has been of considerable importance in studies of the properties of samples of steel, in particular the investigation of ferromagnetic hysteresis and the magnetomechanical effect. As a result, exact algorithms for the demagnetization of samples and for obtaining the anhysteretic or ideal magnetization curve have been devised.
18 Dec 1984
TL;DR: In this article, the authors investigated the optical hysteresis properties of an optically linear dielectric film embedded in dissimilar optically nonlinear unbounded media, and showed that the eigenvalue equation yields a relation between the guided-wave vector and the field amplitude at the boundary.
Abstract: TE guiding structures consisting of an optically linear dielectric film embedded in dissimilar optically nonlinear unbounded media, are investigated for hysteresis properties. It is shown that many important features can be determined without a knowledge of the electric fields in the nonlinear media and that the eigenvalue equation yields a relation between the guided-wave vector and the field amplitude at the boundary. The power in the system is the important physical quantity and is carried by asymmetric modes that, in the linear limit, are neither odd nor even. This paper explores some of the limitations of such asymmetrically loaded linear dielectric films and shows that they can exhibit optical hysteresis.
01 Jul 1984
TL;DR: In this article, the authors show that all forms of hysteresis can be attributed to structural factors, such as void structure of the solid, a shift in contact angle between intrusion and extrusion, or a combination of both in specific cases.
Abstract: The cause of hysteresis between the intrusion and extrusion curves in mercury porosimetry has usually been attributed to (1) the void structure of the solid, (2) a shift in contact angle between intrusion and extrusion, or (3) a combination of both in specific cases. Our studies indicate that all forms of hysteresis can be attributed to structural factors. Intrinsic contact angle shifts in porosimetry are thermodynamically and experimentally inconsistent.
TL;DR: In this article, a non-dimensional scale model of hysteresis of unsaturated porous mixtures is proposed, using the effective saturation rather than the capillary head as the independent variable.
Abstract: A previously developed model of hysteresis is formulated on a nondimensional scale using the effective saturation rather than the capillary head as the independent variable. The theoretical equations of the various hysteretic curves suggest that a universal hysteresis of unsaturated porous m
TL;DR: In this paper, the general formation mechanism of magnetic thin films, the field of relevant parameters and the dependance of magnetic properties on the essential parameters are discussed and demonstrated by a few examples of hysteresis loops.
Abstract: The vacuum deposition of ferromagnetic material at oblique incidence will become a major production technology for magnetic tapes for longitudinal recording applications in the future. In this paper the general formation mechanism of magnetic thin films, the field of relevant parameters and the dependance of magnetic properties on the essential parameters is discussed and demonstrated by a few examples of hysteresis loops: The resulting layout of laboratory and pilot production equipment developed so far for this application is demonstrated. For typical application examples, the material efficiency of the systems has been calculated as a function of the used incidence angle range. Also the differential increase in layer thickness as a function of incidence angle has been calculated in order to get a simple model for the formation of microcolumns.
TL;DR: A crystal chemical study carried out on phosphate single crystals with the formula AIBIIPO4 (AI=Na, K; BII=Ca, Zn, Sr, Cd, Ba, Pb) has permitted to follow the evolution of the crystal symmetry inside these series as discussed by the authors.
Abstract: A crystal chemical study carried out on phosphate single crystals with the formula AIBIIPO4 (AI=Na, K; BII=Ca, Zn, Sr, Cd, Ba, Pb) has permitted to follow the evolution of the crystal symmetry inside these series. Second harmonic generation (SHG) tests held on powder or small single crystals and hysteresis loops displayed on ceramic samples confirmed the existence of ferroelectricity in these material series.
TL;DR: In this paper, two disordered alloys, Au81Fe19 and Ni79Mn21, were cooled from ∼ 100 K down to different temperatures in the range 1.2 K < T < 40 K, either in zero field or in a field ranging from 50 G to 28 kG.
Abstract: Two disordered alloys, Au81Fe19 and Ni79Mn 21, were cooled from ∼ 100 K down to different temperatures in the range 1.2 K < T < 40 K, either in zero field or in a field ranging from 50 G to 28 kG. Their low-field hysteresis loops were then measured Near and above some characteristic temperature, TAT, identified as the de Almeida-Thouless temperature, the hysteresis loops of both alloys present essentially the same shape as for standard ferromagnets. Well below TAT, the loops become quite large and are very different in shape both from the standard ferromagnetic case and from one alloy to another. Memory effects, induced by field cooling, are found to have very different stabilities in the two alloys. In Au 81Fe19, they are highly unstable and easily washed out by cycling an applied field of a few hundreds gauss at 1.5 K. In the Ni 79Mn21 alloy, they are remarkably stable whatever the cycling field (T = 1.5 K) in the available range ± 28 kG. Large hysteresis losses set in below TAT and increase very rapidly in a narrow temperature region defined as the de Almeida-Thouless cross-over region. It is suggested that the low field behaviour of Ni79Mn21 cooled in zero field is determined by the appearance of unidirectional anisotropy fields during cooling. These fields would have approximately the same domain structure as the spontaneous magnetization and would be created by the molecular field of this magnetization.
TL;DR: In this article, the authors studied boundary-value problems in a theory recently proposed to model linear elastic materials with voids, and they showed that the model exhibits stress relaxation, hysteresis, and failure.
Abstract: I study several specific boundary-value problems in a theory recently proposed to model linear elastic materials with voids. I show that, in addition to the known fact that the model exhibits stress relaxation, it also exhibits creep, hysteresis, and a phenomenon which can be interpreted as failure. In order to maintain plausible physical behavior, I suggest an a priori inequality not contained in the original theory.
TL;DR: In this paper, a new method has been suggested for determining an analytical expression for the hysteresis loop of the transformers and non-linear reactors from the manufacturer's data giving the conventional RMS saturation curve and no load loss.
Abstract: A new method has been suggested for determining an analytical expression for the hysteresis loop of the transformers and non-linear reactors from the manufacturer's data giving the conventional RMS saturation curve and no load loss. The accuracy of the technique is verified by the experimental results. The analytical expression thus proposed also exhibits the hysteretic property of increasing the loop area with increase of frequency of operation. Furthermore the energy loss expression associated with the hysteresis loop is derived from the suggested expression.
TL;DR: In this article, the hysteresis variations of a 2D-layer charge QS with a gate voltage Vg or with a magnetic field H, were investigated, and they showed that at sufficiently low temperature T < 1K the relaxation time of a nonequilibrium state is much higher than 103 sec.
TL;DR: Amorphous thin films of Sm 100-x Co x (75 ) were prepared by vacuum deposition in a magnetic field as discussed by the authors, and the preparation conditions and magnetic properties of the films were described.
Abstract: Amorphous thin films of Sm 100-x Co x ( 75 ) were prepared by vacuum deposition in a magnetic field. The preparation conditions and magnetic properties are described. The films exhibit a pronounced uniaxial anisotropy in the film plane with a rectangular shaped hysteresis loop. The magnetization and coercivity are mainly determined by composition. With increasing Sm content the coercivity increases from 30 to 100 kA/m. The magnetization reversal is studied by the angular dependence of the hysteresis properties and by domain observations indicating a nonuniform reversal process. The recording performance measured on 5-in disks shows an improvement in recording density and signal-to-noise ratio compared to traditional longitudinal recording media.
TL;DR: In this paper, a ferroelectric loop tracer is described, which allows continuous compensation for stray capacitances and resistive losses of the sample, and works at various frequencies, here 0.1 Hz to 100 Hz, and plots the hysteresis loops at various scales directly onto a chart recorder.
Abstract: A new type of ferroelectric loop tracer is described which allows continuous compensation for stray capacitances and resistive losses of the sample. The loop tracer works at various frequencies, here 0.1 Hz to 100 Hz, and plots the hysteresis loops at various scales directly onto a chart recorder. A facility exists for sampling any point on the hysteresis loop, thus alloying the loop parameters to be monitored as a function of temperature, frequency, etc. The applied signal, in contrast to the normally used sine wave, is triangular.
TL;DR: Hysteresis in the discharge characteristics of a low pressure (p≂10−4 Torr), magnetized argon plasma column is reported in this article, with sudden jumps in plasma density and discharge current as either the discharge voltage or magnetic field strength is varied.
Abstract: Hysteresis in the discharge characteristics of a low pressure (p≂10−4 Torr), magnetized argon plasma column is reported. The hysteresis is associated with sudden jumps in plasma density and discharge current as either the discharge voltage or magnetic field strength is varied. A substantial change in the plasma density profile and the appearance of coherent plasma oscillations are also observed.
TL;DR: In this article, sensitive dielectric measurements reveal hysteresis effects throughout the incommensurate phase of Rb2ZnCl4, and the defect structure is described.
Abstract: Sensitive dielectric measurements reveal hysteresis effects throughout the incommensurate phase of Rb2ZnCl4. Differences between various incommensurate ferroelectrics are referred to different mobilities of discommensurations and to details of the defect structure.
TL;DR: In this paper, the development of the current carrying charge density wave state was studied in orthorhombic TaS 3 through direct current-voltage measurements, and through the study of low frequency time dependent phenomena.
TL;DR: A review of friction theories relevant to the interaction between magnetic-recording-device components (hard, inelastic materials) and viscoelastic polymeric materials used in the manufacture of flexible, magnetic tape is presented in this paper.
Abstract: A review of friction theories relevant to the interaction between magnetic-recording-device components (hard, inelastic materials) and viscoelastic, polymeric materials used in the manufacture of flexible, magnetic tape is presented. Tabor's classical theory of adhesion with appropriate deformation and shear-strain rates, as well as Hegmon's theory of hysteresis friction, adequately describes the frictional behavior. Other sources of adhesional friction are stiction, meniscus, and microcapillary evacuation. For magnetic-recording-tape applications, the adhesion component of friction is responsible for the major part of the observed friction, except near the softening temperature for the magnetic-coating layer, where the loss tangent becomes very high, or in the case of rough surfaces for which hysteresis friction is significant. From a magnetic-tape design standpoint, the real area of contact (which directly affects adhesional friction) can be minimized by increasing the complex modulus of elasticity of t...