Magnetostriction surface

Szymczak (1997, 1999) has stressed the possibility to distinguish between pure interface effects, i.e. surface magnetostriction, and the effects of an interface diffusion layer. Since magnetic anisotropy and magnetostriction have the same origin, the surface magnetostriction is expected to have an intrinsic character. In Szymczak s notation (Voigt... 

M The magnetostriction of terbium alloys has already found many applications. Most recently it was discovered that its compounds can be precipitated on surfaces in highly ordered molecular arrays this promises interesting effects. 

Here, the parameter k expresses the changes of the magnetostriction due to the change in composition of the residual amorphous matrix with the evolution of crystallisation. In fact, a linear approximation A.am(p) = A.am(0) + kp is applied. The last term describes the surface effects in which R is the effective radius of the grains, i.e. 3IR is the surface to volume ratio for the spherical grains (5/ V in table 4). Figure 69a shows the... 

The existence of the surface contribution to the effective magnetostriction of nanocrystalline alloys has been confirmed theoretically in terms of the dipolar model (Szumiata et al. 1999). These authors showed that, due to the limited radius of the nanoparticles, additional magnetostrictive stresses are localised at the interfaces. The evaluation of the influence of the dipolar interaction on the magnetostriction in crystalline grains of perfect spherical shape surrounded by a magnetic environment of about 0.S nm with either crystalline or amorphous structure has been calculated. A similar method was previously used to obtain the surface and volume anisotropy (Draaisma and de Jonge 1988) and to... 

Because of surface contributions as well as due to interface strains, the magnetostriction of thin films is expected to be different from that observed in bulk materials. Motivated by this observation and by possible technical applications of thin films of manganites and cobaltites, we decided to present in this paper mostly results of investigations of magnetostrictive effects in thin films. It has to be mentioned that no data exist in the literature on magnetostriction of cobaltite thin films. 

Figure 9.3. Operation of non-contact transducer performance. (A) Magnetostrictive and (B) electromagnetic type, (a) The sampie, wrapped in a soienoid, is piaced inside a magnetic fieid. (b) Lorentz forces generated on the sampie surface. DMF — direction of the magnetic fieid and S — soienoid. (Reproduced with permission of Eisevier, Ref [16].)...

To produce a high quality surface (10-12), it is necessary to avoid a discontinuous flow of the melt through the profiling channel. A high quality profile with a polished surface is produced with degradation of the polymer surface as a consequence of the effect of the magnetostrictive transducer. The ultrasonic oscillations reduce the toughness of the polymer and the resistance of the wall affect the melt flow at the channel boundary. 

It was found that a horizontal installation, with the magnetostrictive sensor axis parallel to the liquid surface, was mandatory for repeatable operation. One manufacturer preferred a 15° inclination to the horizontal, w hich appeared to be most suitable for his particular probe tip design. A variety of probe configurations were tested. The majority of the units utilized a diaphragm as the sensing element. 

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