Dependence of the magnetocaloric effect in superparamagnetic nanocomposites on the distribution of magnetic moment size

Magnetocaloric effect in ferrite nanoparticles

“…In comparison to the bulk materials that show giant MCE, the values for the entropy change shown in this work are still quite small but are significantly higher than what has been reported so far for several other iron or ironoxide-based nanoparticle systems. This is associated with stronger inter-particle interactions in our samples and consistent with models that indicate that introducing some amount of interactions could lead to higher entropy change in comparison to strictly non-interacting superparamagnetic particles [8]. To further enhance the change in the magnetic entropy change for nanoparticles systems, we need to further control the size dispersion, inter-particle interaction and generally explore other materials with higher magnetic moments.…”

“…To date, not too many studies of the MCE in nanocomposites have been reported [8][9][10][11][12]. Even though these reports indicate an enhanced MCE due to the reduction of grain size to the nanoscale dimensions, the overall effect is quite low due to the fact that the nanoparticles have to be dispersed in a matrix in order to prevent the agglomeration associated with the surface energy minimization.…”

Recent developments in magnetocaloric materials

“…It is well established [213] that nanostructuring may lead to a nanoparticle exhibiting an effective magnetic moment which is greater than the magnetic moments of the constituent atoms. Thus, Yamamoto et al [214] examined how the magnitude of the effective magnetic moment influences the resulting MCE of 12 at% Fe to 33 at% Fe iron oxide nanoparticles ranging in size from 10 to 30 nm which were embedded in a silver matrix. They concluded that for a maximum enhancement of the MCE, it is desirable to have as uniform distribution as possible of particle sizes because the latter controls their effective magnetic moments.…”

Structural study and large magnetocaloric entropy change at room temperature of La1−x□xMnO3 compounds

“…[9][10][11][12] Nanomaterials are expected to bring new features to the magnetocaloric effect (MCE) and magnetic properties compared to bulk materials. 13,14 We note that there are numerous complex physical phenomena of manganites such as the charge ordering (CO). Swain et al have shown that this phenomenon exists in nanomaterials.…”