Here we demonstrate electric-field induced magnetic anisotropy in a multiferroic composite containing nickel nanocrystals strain coupled to a piezoelectric substrate. This system can be switched between a superparamagnetic state and a single-domain ferromagnetic state at room temperature. The nanocrystals show a shift in the blocking temperature of 40 K upon electric poling. We believe this is ...

We summarize the basic concepts beneath the idea of superparamagnetism and introduce the Monte Carlo (MC) method as a powerful tool for studying superparamagnetic (SPM) properties. Starting with the description of the physical features of the single-domain SPM entities, we concentrate on their special magnetic properties as a function of time, temperature, and applied magnetic field. Then, we g...

A crosslinker anchoring process was developed to synthesize Fe(3)O(4)/NaYF(4):Yb,Er hetero-nanoparticles (NPs) with dual properties of superparamagnetism and upconversion (UC) emission. After ligand ozonolysis treatment, these NPs could be well dispersed in water.

Well-defined CoFe2O4 nanoparticles embedded in amorphous SiO2 matrix have been synthesized by sol-gel method, characterized and investigated by Mössbauer spectroscopy and magnetic measurements. The mean particle size was found to increase from 3 to 15 nm by varying the temperature of a subsequent annealing from 800 to 1100 ◦C. The composites exhibited superparamagnetic behavior with the blockin...