Effect of a Dc Oblique Magnetic Field on the Magnetic Susceptibility of the Super-Paramagnetics Nanoparticles in Very Low Damping

The Magnetic Susceptibility of an individual Super-Paramagnetic nanoparticle in a presence of DC Oblique magnetic fields of arbitrary amplitude is investigated using Brown’s continuous diffusion model. The susceptibility is calculated and compared when for extensive ranges of the anisotropy, the dc magnetic fields in the very low damping with Matrix continued Fraction. It is shown that the shape of the Spectrum of Super-Paramagnetic nanoparticles is substantially altered by applying a dc oblique field. There is also an inherent geometric dependence of the complex susceptibility on the damping parameter arising from coupling of longitudinal and transverse relaxation modes

Interferometric tracking

The purpose of this chapter is to present a survey of passive microrheology techniques that are important complements to more widely used particle tracking and light scattering methods. Such methods include back focal plane interferometry and extensions of particle tracking to measure the rotation of colloidal particles. Methods of passive microrheology using back focal plane interferometry are presented, including the experimental design and detector sensitivity and limits in frequency bandwidth and spatial resolution. The Generalized Stokes Einstein relation is derived from linear response theory of the particle position power spectrum and complex susceptibility. Applications of interoferometric tracking include high frequency microrheology and two-point measurements. Lastly, the chapter includes a discussion of rotational passive microrheology and the rotational GSER.