Curve, hysteresis

Figure 1. Schematic diagram of a hysteresis curve for a typical ferromagnet showing magnetization (a) as a function of the applied magnetic field (H) Saturation magnetization Is Indicated by Os- Inset shows the multidomain structure and subdomain superparamagnetlc clusters.

Figure 2. Plot of relative magnetization, a/Os ns a function of H/T. (a) A paramagnetic system Is characterized by an effective magnetic moment, with a Bohr Magneton number vlO per Ion, and by the absence of hysteresis. Paramagnetic saturation occurs at very high "H/T" == 10 Oe K"l. (b) l.angevln curve for S.P. clusters, (c) Part of a ferromagnetic hysteresis curve.

Figure 17. The magnetization hysteresis curve at 300 K of SmCos nanoparticles prepared from SnCF and Cofacacfs in the presence of PVP at 573 K. (Reprinted from Ref [235], 2006, with permission from Wiley-VCH.)...

Hysteresis curve of a ferroelectric crystal, v = initial (virginal) curve, Pr = remanent polarization, Ps = spontaneous polarization, Ec = coercive field... 

Hysteresis curves for a magnetically hard and a magnetically soft ferromagnetic material. S = saturation magnetization, R = remanent magnetization, K = coercive force... 

Figure 10.5 Magnetic hysteresis curve recorded on a 1 1 diluted powder sample in the isostructural Y3+ compound at 1.8K. (Reprinted from Ref. [29b]. Copyright (2011) American Chemical Society.)...

Fig. 13 A typical hysteresis curve for a sample with extended ferromagnetic coupling (see page 239).

One of the more useful functions of the DC Sweep is to plot transfer curves. A transfer curve usually plots an input versus an output. A DC transfer curve plots an input versus an output, assuming all capacitors are open circuits and all inductors are short circuits. In a DC Sweep, all capacitors are replaced by open circuits and all inductors are replaced by short circuits. Thus the DC Sweep is ideal for DC transfer curves. The Transient Analysis can also be used for DC transfer curves, but you must run the analysis with low-frequency waveforms to eliminate the effects of capacitance and inductance. Usually a DC Sweep works better for a transfer curve. The one place where a transient analysis works better is plotting a hysteresis curve for a Schmitt Trigger. For a Schmitt Trigger, the input must go from positive to negative, and then from negative to positive to trace out the entire hysteresis loop. This is not possible with a DC Sweep. 

The next thing we would like to do is plot the hysteresis curve for this Schmitt Trigger. The hysteresis curve is a plot of V0 versus V N. We must delete the trace Vfl/IN/. Click the LEFT mouse button on the text V(VlNf. It should turn red, indicating that it has been selected. To delete the trace, press the DELETE key. You should have the Probe screen shown... 

Click the OK button twice to accept the changes and view the trace. You should see the hysteresis curve ... 

SDLUTIDI1 Use the sinusoidal voltage source. The input and output waveforms are shown on the left screen capture, and the hysteresis curve is shown on the right screen capture. 

The type B hysteresis curve is associated with slit-shaped pores or the space between parallel plates. Type C hysteresis is produced by a mixture of tapered or wedge-shaped pores with open ends. Type D curves are also produced by tapered or wedge-shaped pores but with narrow necks at one or both open ends. Type E hysteresis results from McBain s bottleneck pores. In pores of this shape, emptying of the wide portion will be delayed during desorption until the narrow neck can evaporate. Therefore, the desorption curve exhibits a small slope at high relative pressures and a large slope where the wide part of the pore empties. 

Porosimetry curves exhibit various shapes. If hysteresis were caused by ink-bottle pores only one shape hysteresis curve should be observed. 

Substances used as permanent magnets need a large coercive force, so that they are not easily demagnetised and preferably should also have a large remanent magnetisation. These substances have fat hysteresis curves. They are often made from... 

This equation has a root lying between and 3 provided ku is less than 37- This root then gives the lower limit on the range of x. As ku tends to 37, so the lower limit on x tends to 3, which is the value at which / becomes zero. Thus for ku = 37, the hysteresis curve disappears from the physically acceptable region (positive quadrant) of the P0-k2 parameter plane. 

Addition of galactomannan to agarose-water systems profoundly alters the optical rotation behavior. Thus, both in the absence and presence of locust-bean gum, there is, below 35°, a sharp shift in optical rotation. However, these shifts are opposite in sign, as shown in Fig. 6. The reheating curves also differ, in that, when locust-bean gum is present, a butterfly-shaped hysteresis curve is obtained.40... 

In Figure 2, the height of the specimens is plotted against the load exerted on the piston, P, in Mp, at various temperatures. To give a clearer picture, only the measurements made at one temperature (156° C.) are shown. Similarly, the hysteresis curves produced by seal friction are given only once. The mean values are given for all other temperatures. 

The magnetic properties may be determined by measurement of hysteresis curves on the powder or magnetic tape. 

A quantitative study of the process indicates that, as the field intensity H increases, the magnetic induction B also increases in a manner characteristic of the substance, This is conveniently represented by a graph, which is called the magnetization curve. See Fig. 1. Its initial slope is the initial permeability (/Xo). If H is carried to some maximum value H , and then reduced (to - //,), R follows the dotted hysteresis curve. B does not fall off as it was built up (solid line) the residual induction B, is... 

Magnetization hysteresis curves for the powder samples of Sm2Fei7N>, are compared to that of the raw powder material (Figure 10.10), and their fundamental magnetic properties are summarized in Table 10.5. The powder sample obtained by ball-milling in pure hexane showed only a small hysteresis loop (curve a), and the Br and iHc values were 1.00 T and... 

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