Magnetic hysteresis, loss

The real part is the magnetic permeability whereas the imaginary part is the magnetic loss. These losses are quite different from hysteresis or eddy current losses, because they are induced by domain wall and electron-spin resonance. These materials should be placed at position of magnetic field maxima for optimum absorption of microwave energy. For transition metal oxides such as iron, nickel, and cobalt magnetic losses are high. These powders can, therefore, be used as lossy impurities or additives to induce losses within solids for which dielectric loss is too small. 

Soft ferriles have a slender S-shaped hysteresis loop with low rcntanencc and low ciicreivc force permitting easy magnetization and demagnetization with little magnetic loss. These ferrites are uniquely suited to low-ioss inductor and transformer cores for radio, television, and carrier telephony. 

Because of hysteresis, energy is dissipated as heat in a magnetic material as it is taken round a complete B-H loop, and the hysteresis energy loss Wh per unit volume of material is... 

The anisotropic continuum approach to losses in multifilament conductors was first conceived by Carr, who developed the model assuming that the inductor is a continuum material with anisotropic resistivity. He applied this approach to the special case of losses in cylindrical conductors for applied transverse sinusoidal fields in the absence of transport current [ ]. Those losses resulting from pJ in the conductor are classified as eddy current or saturation hysteresis losses, depending upon the level of /. Eddy current losses result from J below Jc, with the implicit assumption of rapidly rising resistivity in the flux-flow regime with currents saturated at Jc. The magnetization loss for the continuum is essentially the magnetic hysteresis loss for the filaments times the fraction of the composite occupied by the filaments. 

Magnetic particles generate heat under AC magnetic fields due to the magnetic losses that arise from the various processes of magnetization reversal (i) hysteresis ... 

The causes of magnetic loss have been studied for a long time, and are divided into (a) hysteresis loss (b) eddy current loss and (c) residual loss. The contribution of each loss toward high-frequency loss of metal magnetic materials and ferrite is typically shown in Figure 6.1.4. Hysteresis loss is equivalent to... 

The physical basis of the use of Fe— Si alloys, commonly called silicon steels, as soft magnetic materials is the fact that both the magnetocrystalline anisotropy isTi and the magnetostriction parameters >.100 and Xm of Fe approach zero with increasing Si content (see Fig. 4.3-5a). The lower the magnitude of these two intrinsic magnetic properties is, the lower are the coercivity He and the AC magnetic losses The total losses ppe consist of the static hysteresis losses p y and the dynamic eddy current losses pw which may be subdivided into a classical p c and an anomalous p eddy current loss term. 

Figure 1.10 Hysteresis loop and magnetizing curve illustrating hysteresis loss...

Hysteresis losses, caused by cyclic magnetization of steel. 

Core loss is the magnetizing or hysteresis loss and represents the iron loss of the machine. 

Excessive healing of magnetic cores, as a result of harmonic frequencies due to hysteresis and eddy current losses (equations (1.I2) and (1.13)). 

The Enclosure is of non-magnetic material, therefore it will be devoid of hysteresis and eddy current losses. 

These balanced enclosure currents also induce electric fields into nearby structures, RCC beams and columns in the same way as the main conductors, and hence nullify most of the space magnetic fields. These space fields (fields outside the enclosure) are otherwise responsible for causing eddy current and hysteresis losses in the metallic (magnetic) structures, RCC beams and columns in the vicinity. The electrical bonding of enclosures thus... 

The enclosure is constructed of non-magnetic material, generally aluminium, in view of its low cost and weight as compared to copper The nonmagnetic material eliminates hysteresis and eddy current losses in the enclosure, as i result of mutual induction,... 

The influence of a induced field on a metallic (magnetic) structure is in the form of closed magnetic loops, which cause hysteresis and eddy current losses. These closed loops cannot be broken by insulating magnetic structures at bends or joints or any other locations. (Refer to Figure 28.32 for more clarity.) There is thus no treatment that can be applied to such structures or bodies in the vicinity of an IPB to protect them from the magnetic effects of the field if present in the space. 

Because these analysers do not employ magnets, peak switching for selected ion monitoring can be done more quickly without hysteresis effects, which makes this system ideal for depth profiling, where it is necessary constantly to switch among masses. These instruments do have the disadvantage of loss of transmission and mass... 

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