Exchange bias and surface effects in bimagneticCoO−core/Co0.5Ni0.5Fe2O4

Effects of Zn Substitution in the Magnetic and Morphological Properties of Fe-Oxide-Based Core–Shell Nanoparticles Produced in a Single Chemical Synthesis

“…These results are consistent with the formation of Fe 1– y O, at the initial stage of the synthesis, followed by the formation of the ferrite phase as a consequence of the surface oxidation, which are in agreement with the PIXE analysis. This growth mechanism leads to the formation of well-defined interfaces, when they are compared with systems where the shell is grown in a second reaction, , with the expectation of an improved magnetic exchange interaction between the phases. Other interesting feature is the reduction in the Zn incorporation in the formed material related to the nominal composition, which is probably related with the well-known low solubility of Zn in the Wüstite structure mentioned before …”

“…As pointed out by Chen et al 20 , the Wüstite phase is formed as consequence of reactions involving some commonly used hydrocarbon solvents and its formation contributes to significant cationic disorder. The later formation of the bimagnetic core-shell system due to the surface oxidation of Wüstite results in very distinct magnetic properties with respect to the monophasic nanoparticles [21][22][23][24][25][26] . Therefore, it is very important determine the factors that govern the core/shell nanoparticles formation to establish the reproducibility of this synthesis method and the magnetic response of the system.…”

“…Other works report on the formation of Fe 1– y O and a ferrite phase in a core–shell structure after oxidation by the thermal decomposition method. − As pointed out by Chen et al, the Wüstite phase is formed as a consequence of reactions involving some commonly used hydrocarbon solvents and its formation contributes to a significant cationic disorder. The latter formation of the bimagnetic core–shell system due to the surface oxidation of Wüstite results in very distinct magnetic properties with respect to the monophasic nanoparticles. − Therefore, it is very important to determine the factors that govern the formation of core–shell nanoparticles to establish the reproducibility of this synthesis method and the magnetic response of the system. Different magnetic ions present different degrees of solubility in the Wüstite phase.…”

Tunnel Magnetoresistance in Self-Assemblies of Exchange-Coupled Core/Shell Nanoparticles

“…[27] In this regard, an exciting possibility is the fabrication of devices based on self-assemblies of exchange coupled core/shell MNPs with tailored magnetic properties. [28] The coercive field in these systems can be finely modified through the interface magnetic coupling [29][30][31][32][33][34],…”

Adjusting the Néel relaxation time of Fe3O4/Zn x Co1−x Fe2O4 core/shell nanoparticles for optimal heat generation in magnetic hyperthermia

“…For this sample, the frequency dependence of the ´´ peaks is successfully fitted with the phenomenological Vogel-Fulcher law as shown in Fig. S5, [54] resulted in  0 = 2(1) 10 -11 s. When the Zn concentration decreases, the fitting of the frequency dependence peaks gives non-physical values of  0 , in the 10 -5 -10 -7 s range. This indicates that these exchange coupled core/shell systems with larger magnetic anisotropy are outside of the applicability of the model.…”