Ferromagnetic Solids

Strong-force interaction (nuclear scattering) Magnetic interaction Position of nuclei in solid (lattice structure) Position and orientation of electronic magnetic moments in solids (ferromagnetism, antiferromagnetism) Lattice vibrations (phonons) Spin excitations (magnons, spin waves)... 

As already described, a magnetic fluid is a stable colloidal dispersion of solid ferromagnetic particles with subdomain sizes in a dispersant. The concentration of particles in a dispersant can be as high as 10 /m. Historically, materials similar to magnetic fluids were prepared by dispersing a ferromagnetic powder, such as iron carbonyl, with diameters (d) of... 

Figure A2.5.16. The coexistence curve, = KI(2R) versus mole fraction v for a simple mixture. Also shown as an abscissa is the order parameter s, which makes the diagram equally applicable to order-disorder phenomena in solids and to ferromagnetism. The dotted curve is the spinodal.

In this chapter piezoelectric crystals and polymers ferroelectric and ferromagnetic solids resistance of metals shock-induced electrical polarization electrochemistry elastic-plastic physical properties. 

In this chapter studies of physical effects within the elastic deformation range were extended into stress regions where there are substantial contributions to physical processes from both elastic and inelastic deformation. Those studies include the piezoelectric responses of the piezoelectric crystals, quartz and lithium niobate, similar work on the piezoelectric polymer PVDF, ferroelectric solids, and ferromagnetic alloys which exhibit second- and first-order phase transformations. The resistance of metals has been investigated along with the distinctive shock phenomenon, shock-induced polarization. 

Let us mention some examples, that is, the passivation potential at which a metal surface suddenly changes from an active to a passive state, and the activation potential at which a metal surface that is passivated resumes active dissolution. In these cases, a drastic change in the corrosion rate is observed before and after the characteristic value of electrode potential. We can see such phenomena in thermodynamic phase transitions, e.g., from solid to liquid, from ferromagnetism to paramagnetism, and vice versa.3 All these phenomena are characterized by certain values... 

Fig. 1. Comparison of experimental values (solid curves) and predicted values (dashed lines) of the saturation ferromagnetic moment per atom, in Bohr magnetons, for Fe-Co, Co-Ni, and Ni-Cu alloys. The short vertical lines indicate change in crystal structure (from Ref. (2)).

The term ferromagnetism reflects the fact that iron shows this effect, but it is by no means restricted to iron or iron compounds. Ferromagnetism is a cooperative phenomenon, i.e. many particles in a solid behave in a coupled manner. Paramagnetic atoms or ions exert influence on each other over extended regions. 

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