Saturation field, magnetic

Becker, E. W. Walcher, W. Image defects in a mass spectrometer due to space charge and magnetic field saturation. Z. Physik 1952,131,395 107. 

Figure B2.4.6. Results of an offset-saturation expermient for measuring the spin-spin relaxation time, T. In this experiment, the signal is irradiated at some offset from resonance until a steady state is achieved. The partially saturated z magnetization is then measured with a kH pulse. This figure shows a plot of the z magnetization as a fiinction of the offset of the saturating field from resonance. Circles represent measured data the line is a non-linear least-squares fit. The signal is nonnal when the saturation is far away, and dips to a minimum on resonance. The width of this dip gives T, independent of magnetic field inliomogeneity.

If the strength of the saturating RF, A B2, and the spin-lattice relaxation time, Jj, are known, then can be measured, again free of magnetic field inliomogeneities. 

If a very high field is appHed the magnetisation can reach its saturated state ia which all the magnetic dipoles are aligned ia the direction of the field. If the magnetic field is switched off, the remanent magnetisation M is left. If the M (or B) is then reduced to sero, a special field strength, the coercivity, is required. 

Fig. 1. Schematic of magnetic flux leakage tests where H,B represents an external appHed magnetic field. See text, (a) Saturated material having no crack,...

Note The speed of the motor ean be varied by vai-ying the frequeney alone but this docs not provide satisfactory performance, A variation in frequeney causes an inverse variation in the flux, for the same system voltage. The strength of magnetic field, p, develops, the torque and moves the rotor, but at lower speeds. / would be reduced, which would raise 0 , and lead the magnetic circuit to saturation. For higher s )ccds, / would be r.nised, but that would reduee which would adversely diminish the torque. Hence frequency variation alone is not recommended practice for speed control. The recommended practiee is to keep V/fas constant, to maintain the motor s vital operatin.c parameters, i.e. its torque and 0 ,. within acceptable limits. 

In Fig.. I we present the temperature dependence of the conductance for one of the CNTs, measured by means of a three-probe technique, in respectively zero magnetic field, 7 T and 14 T. The zero-field results showed a logarithmic decrease of the conductance at higher temperature, followed by a saturation of the conductance at very low temperature. At zero magnetic field the saturation occurs at a critical temperature, = 0.2 K, which shifts to higher temperatures in the presence of a magnetic field. 

Figure 4-228. Magnetic flux-lines representation in a highly permeable iron alloy core saturated with an auxiliary magnetic field.

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.

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