Superparamagnetic-blocked state transition under alternating magnetic fields: towards determining the magnetic anisotropy in magnetic suspensions

Abstract

The potential of magnetic nanoparticles for acting as efficient catalysts, imaging tracers or heating mediators under alternating magnetic fields grounds on their superparamagnetic behaviour. In spite of the relevance of...

Spin Selectivity Induced by the Interface Effect for Boosted Water Oxidation

“…In contrast, NiFe-LDH shows a nonzero coercivity (11 Oe) at room temperature with a linear magnetization response upon application of an external magnetic field, suggesting the paramagnetic behavior of NiFe-LDH. Most notably, an increased coercivity (74 Oe) has been observed from the hysteresis curve of Co 3 O 4 @NiFe-LDH with a saturation tendency, indicating its superparamagnetic property. , This conclusion is further supported by the observed blocking temperature of 42 K as shown in the zero-field-cooled (ZFC) magnetization curve of Co 3 O 4 @NiFe-LDH (Figure e). These analysis results imply the strong interface effect-induced magnetic exchange interaction between Co 3 O 4 and NiFe-LDH under ambient conditions. , …”

Multiparametric modulation of magnetic transduction for biomolecular sensing in liquids

“…Such a time lag tailors the opening of AC magnetization cycles. 51 Moreover, field intensity ( H 0 ) defines both the number of the MNP magnetic moments aligned with respect to the external field direction and the magnetic regime (linear or non-linear) in which magnetization dynamics occur. In this manner, the field frequency and intensity probe MNP magnetic relaxation, defining the shape and values of AC magnetization cycles, as shown in Fig.…”

“…Such transduction signal reflected in AC magnetization changes has been probed by ACM under alternating magnetic fields whose field frequency ranges from 10 to 300 kHz and intensities up to 24 kA m −1 . Recent works 51 have shown the relevance of field conditions (i.e., field frequency and intensity value) to define a measurement time (τ M ) in order to probe the dynamic magnetization loops. Indeed, we took advantage of selecting field conditions to optimize the observation of alterations of magnetic relaxation times following b-MNP nano-assembly or nano-cluster formation.…”

Origin of Enhancement of Orbital Magnetic Moment in SiO2-Coated Fe3O4 Nanocomposites Studied by X-ray Magnetic Circular Dichroism

“…Smaller nanometric particles produce an appreciable response for more effective observation with these features. In contrast to the bulk value of 126 Oe, 24 the thin film value of 50 Oe, 25 and the value of 65 Oe for a microfabricated Fe 3 O 4 thin film, 26 Fe 3 O 4 NPs prepared using this approach had an H c as high as 900 Oe at room temperature (RT). 27 These numbers correspond to the 400 Oe values that were observed for Fe 3 O 4 particulate films 28 in the same sequence.…”