Magnetization remnant

Magnetic properties remnant magnetization, coercive force Morphology... 

Fig. 11.7. The granular ferromagnetic metal magnetization M as a function of an external magnetic field H at temperatures below the blocking temperature. Arrows indicate the direction of the field sweep. Mr remnant magnetization, Ms saturation magnetization, Hc coercivity.

Another example [58] is given by NBu4[CuCr(ox)3], which has a ferromagnetic transition at Tc = 1 K and exhibits remnant magnetization and a hysteresis loop below Tc. 

Initiation of inner-core crystallization and growth, and start-up of core dynamo remnant magnetism in c.2.9Ca rocks... 

Palaeomagnetic dating techniques, which rely upon measuring the chemical remnant magnetism (CRM) preserved by secondary iron minerals within the duricrust, have proved relatively successful. This approach effectively records the cessation of the mineralogical transformations that cause... 

Fig. 42. Magnetization vs temperature curves for (NPr4)2[FeCr(dto)3). RM stands for remnant magnetization. From Okawa et al. 81).

Figure 15.7 Relationship between domains and hysteresis, a) Typical hysteresis loop for a ferromagnet. h) For a virgin sample, // = 0 and M = 0 due to closure domains, (c) With increasing H, the shaded domain which was favorably oriented to H grows by the irreversible movement of domain walls up to point X. (d) Beyond point X, magnetization occurs only by the rotation of the moments, (e) Upon removal of the field, the irreversibility of the domain wall movement results in a remnant magnetization i.e., the solid is now a pennanent magnet.

In order to completely rid the material of its remnant magnetization, the polarity of the magnetizing field has to be reversed. The value of H at which M goes to zero is called the coercive magnetic field intensity (Fig. 15.8 ). 

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