Analytical calculations based on finite-size spin-wave theory and Monte Carlo (MC) simulations are performed to investigate the validity of the well-known relation m(H,T ) = M(H, T )BD[M(H,T )NH/T ] between the induced magnetization m of the magnetic particle and its intrinsic magnetization M for the Ising and isotropic classical models [BD(x) is the Langevin function, D is the number of spin c...

X-ray photoemission electron microscopy combined with x-ray magnetic circular dichroism is used to study the magnetic properties of individual iron nanoparticles with sizes ranging from 20 down to 8 nm. While the magnetocrystalline anisotropy of bulk iron suggests superparamagnetic behavior in this size range, ferromagnetically blocked particles are also found at all sizes. Spontaneous transiti...

We present a study of the magnetic properties of the superparamagnetic ferritin system by employing zero-field (ZF) and longitudinal-field (LF) μSR measurements. Two μ fractions with different depolarisation behaviour are detected, one arising from muons stopped in the organic shell and one from muons stopped in the mineral core. The freezing of the superparamagnetic moments is evident in the t...

We present a novel strategy for patterning single magnetic beads by using digital microfluidics (DMF). A droplet containing a suspension of superparamagnetic particles is transported back and forth over an array of femtoliter-sized microwells by using electrowetting-on-dielectric actuation forces. Compared to existing methods, this technique allows patterning of superparamagnetic beads in micro...

Abstract Substances with superparamagnetism, a special magnetic effect, are magnetized under external field. When the applied field disappears, superparamagnetic substances have almost zero magnetization intensity, quite small coercivity. The performance of powder or suspension used in particle detection greatly affects sensitivity. This paper studies new method for preparing nano-superparamagn...

in this work, we report synthesis of surface modified superparamagnetic iron oxide nanoparticles (spion) by co-precipitation method using feso4.7h2o and fe2(so4)3.5h2o as precursors and trisodium citrate dihydrate as surfactant. surface modification of the as prepared samples was performed in pot by sol-gel precipitation method using tetraethoxysilane (teos). the structure, morphology, and magn...

Sequential superparamagnetic clustering (SSC) is a substantial extension of the superparamagnetic clustering approach (SC). We demonstrate that the novel method is able to master the important problem of inhomogeneous classes in the feature space. By fully exploiting the non-parametric properties of SC, the method is able to find the natural clusters even if they are highly different in shape a...