Transverse susceptibility

Most of the experimental results on CJTE can be explained on the basis of molecular field theory. This is because the interaction between the electron strain and elastic strain is fairly long-range. Employing simple molecular field theory, expressions have been derived for the order parameter, transverse susceptibility, vibronic states, specific heat, and elastic constants. A detailed discussion of the theory and its applications may be found in the excellent review by Gehring Gehring (1975). In Fig. 4.23 various possible situations of different degrees of complexity that can arise in JT systems are presented. 

Experiments using a standard electromagnet can be performed by measuring the strain modulated biased transverse susceptibility (Kraus 1989). In this measurement, a static bias field is applied in the film plane, now perpendicular to the film axis, while the ac driving field is parallel to that axis. The susceptibility (transverse to the bias field) is detected by the pick-up coils and its reciprocal value is then a linear function of both the dc bias field (tfdc) and the magnetoelastic field (Ha = 3As[Pg.109]

For practical calculations of the transverse susceptibility x and of the relevant contribution As of transverse vibrations to the total permittivity, given in the high-frequency approximation by... 

Davis et al. [42] have recently introduced the terms rotator and extender for a variety of ferroelectrics based on oxygen octahedra, in order to classify them with respect to whether the shear or the collinear effect dominates in the piezoelectric response. In extenders, the dominant polarization extension is directly related to the collinear piezoelectric effect, whereas in rotators the dominant contribution to the piezoelectric effect is the polarization rotation, that is directly related to the shear piezoelectric effect. Thus, extenders are ferroelectrics with a large longitudinal piezoelectric coefficient 33 that is related to a large relative dielectric susceptibihty %33, while rotators are ferroelectrics with large shear coefficients dis and 24. which are related to transverse susceptibilities and %2z. correspondingly. Electrostrictive... 

The NMR of the VV ions appears to be a very sensitive mediod to measure tire nonlinear transverse susceptibility in crystals with an axial symmetry. For example, Tm NMR studies of the LiTmF4 crystal at 4.2K in relatively low magnetic fields (<7kOe) have given 3x10" (Al tshuler et al. 1982). 

Fig. 32. Transverse susceptibility (a) Typical data of C Mn 4.7%, obtained at 1.5 K in the cooling field = 11.7 kG, showing perfect agreement with eq. 50, the anisotropy field = KIM, being the only parameter. The isotropic part Xo measured after ZFC, whUe M, (=

Fig. 34. Transverse susceptibility Xx now measured versus (compare with fig, 32) in CuMn 4.7% for = 0. Excellent agreement is found with a purely unidirectional anisotropy energy = 0, dotted line), while the data cannot be explained assuming the ratio given from Xx experiments...

Figure F.8.4. Temperature dependence of the transverse susceptibility y (I2. < =0), the r and a> parameters. (Reproduced with permission from Ref. 131.)...

X+ ) = transverse susceptibility r (q,a ) = electronic quadrupolar suscep tibility... 

Within the random phase approximation (RPA) Izuyama et al. (1963) have shown that the transverse susceptibility can be described by the above Hamiltonian (eq. (56)), which leads to ... 

N -[3-(Trimethoxysilyl)propyl] diethylene triamine transverse susceptibility Curie temperature... 

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