Remanence, magnetic materials

Remanence, magnetic materials, 12-105 to 113 Resistance of wires, 15-37 Resistivity, electrical alloys, 12-41 to 43... 

Particulate Materials. There are three principal classes of particulate magnetic materials y-ferric oxide, y-Fe202, and its modifications chromium dioxide [12018-01 -8] and iron [7439-89-6]. A comparison of the remanent magnetization, and coercivity, for several y-Fe202... 

Maps of the remanent magnetic domain pattern in the near-surfiice region of magnetic material and thin films can be made routinely. 

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

Archaeomagnetism can be considered a branch of Paleomagnetism specifically devoted to the dating of archaeological materials from the measurement of the remanent magnetization achieved by the iron oxide impurities present in clay after cooling of the ceramic artifact. This recording mechanism primarily provides information on the direction of the Earth s field at the time the artifact was fired or the kiln was last used. 

The saturation magnetization Ms is a specific constant for the material and for magnetic iron oxides is principally determined by the Fe2 + ion content. The ratio of remanent magnetization to saturation magnetization (Mr/Ms) for the tape depends mainly on the orientation of the pigment needles with respect to the longitudinal direction of the tape, and should approach the theoretical maximum value of unity as closely as possible. 

Figure 2 shows the two hysteresis loops for a medium and a head material. The coercivity, FT, the saturation magnetization, M or induction, Bs, remanent magnetization, M or induction, B and the permeability, JJ, differ for the two materials. 

The operating state of a permanent magnet lies in the second quadrant of a B-H hysteresis loop since the magnet is always subject to its own demagnetizing field. Apart from its coercivity and remanence, a permanent magnet material is rated by its maximum energy product ... 

Generally, isotropic permanent magnets with a remanence ration JJJS > 0.5 are referred as remanence enhanced materials. However, the theoretical limit for the remanence of noninteracting grains depends on the crystal symmetry, the crystallographic orientation of the easy directions, and the volume fraction and the saturation polarization of the phases. The remanence ratio a two-phase nanocomposite magnet is... 

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