Magnetostriction forced

The forced magnetostriction coefficient should be large since this is inversely proportional to the relative magnetization. 

For a > 0.8, Houmann et al. (1975) found that the field dependence of the Tb y-strain terms was well represented by hf. Above Tn the forced magnetostriction of Tb and Dy (Rhyne 1965) is proportional to in agreement with Callen and Callen (1965). 

Bumagina et al. (1981) and Krotov et al. (1982) used the general formula for the forced magnetostriction presented above, for the interpretation of the low-temperature measurements of the magnetoelastic effects in the crystals of the LiRF4 fluorides. The... 

Fig. 26. Forced magnetostriction in the LiTbF4 Ising ferromagnet (7J =2.885 K) in the longitudinal field solid curves represent experimental data obtained at 4.2 K (1) and 1.6 K (2). The...

Fig. 32. Forced magnetostriction for CeBe,j and YbCuAI and coefRcient of magnetostriction for UPtj versus magnetic field at 7 =4.2K. Data for UPt3 are from de Visser et al. (1986) for YbCuAI and CeBe,j from Hafiier (1985).

Similar to the l Fe2 compounds, the amorphous alloys exhibit a large linear forced magnetostriction. This magnetostriction is large near the Curie temperature. For these alloys AVIVH is of the order of 10" /Oe at room temperature, a value comparable to that of Gd metal at room temperature. 

The major advantages of magnetostrictive systems are that they are of an extremely robust and durable construction and provide very large driving forces. This makes them an attractive proposition for heavy duty industrial processing. There are however... 

The two principle modes of the magnetostriction (A -° and As or Xy-2) introduced above are illustrated in fig. 2. With respect to the non-magnetic fictitious state, a spherical, isotropic sample exhibits a relative volume change AV/V = A" 0, when it becomes magnetic. In addition, when one forces the moments to be directed along an applied magnetic field B, an anisotropic deformation is induced, which transfers the sphere into an ellipsoid with the same volume. 

Alloy Composition Saturation induction, fly, T Coercive force Hc. A/m Magnetostriction. A. x 10 ft... 

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].)...

The onset of ferromagnetism in this system has usually been interpreted in terms of an environmental model. Fe atoms which occupy Al sites are surrounded by 8 Fe nearest neighbours and it is suggested that the percolation of such atoms (with pFc = 2.2pB) on Al sites eventually gives rise to ferromagnetism. The critical concentration does not appear to be significantly different for the two conditions. The forced volume magnetostriction peaks at 4 X 10 9 Oe-1 at 70% Fe for... 

Both crystal (ferromi etic) anisotropy and m netostriction tend to diminish as the Curie point is approached. (The magnetostriction may be regarded as an induced anisotropy brought about by deformation of the crystal by its own magnetic forces.) Hence the hysteresis is... 

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