Solid superparamagnetic

III. Low-Frequency Nonlinear Susceptibilities of Superparamagnetic Particles in Solid Matrices A. Linear and Cubic Dynamic Susceptibilities Numerical Solutions... 

III. LOW-FREQUENCY NONLINEAR SUSCEPTIBILITIES OF SUPERPARAMAGNETIC PARTICLES IN SOLID MATRICES... 

Figure 4.12. Real (a) and imaginary (b) components of the cubic susceptibility of a superparamagnetic assembly with coherently aligned easy axes the direction of the probing field is tilted with respect to the alignment axis at cos P = 0.5 the dimensionless frequency is (DTo = 10-6. Solid lines show the proposed asymptotic formulas taken with the accuracy a 3 circles present the result of numerically exact evaluation dashed lines correspond to the zero derivative approximation (4.167). The discrepancy of the curves is mentioned in the text following Eq. (4.220).

Figure 4.13. Real (a) and imaginary (b) components of the fifth-order susceptibility of a random superparamagnetic assembly the dimensionless frequency is coio = 1CT6. Solid lines show the proposed asymptotic formulas with the accuracy a 3 circles present the result of a numerical evaluation.

Superparamagnetic solids have a net magnetization that enhances the sum of individual moments, all of which can easily reoriented by a small external magnetic field. 

Figure 8 Temperature-dependent Mossbauer spectra of metallic iron nanoparticles in zeolite NaX (a). The superparamagnetic blocking temperature Ti is aroimd 40 K. The solid lines have been calculated by a relaxation formalism assuming a hyperfine field distribution as shown in (b) with a bimodal size distribution of metallic iron particles. (Reprinted from Schiinemann, Winkler, Butzlaff and Trautwein. With kind permission from Springer Science Business Media)...

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