Structural, dielectric and magnetic properties of superparamagnetic zinc ferrite nanoparticles synthesized through coprecipitation technique

Nanosized spinel zinc ferrite was reproducibly synthesized via coprecipitation technique, and effects of variation in digestion temperature on the structural, dielectric and magnetic properties were studied. The crystallite size was found in the range of 4.4–15 nm. X-ray diffraction results revealed that the synthesized materials were of pure normal spinel structure. A very small value of coercivity was observed corresponding to the superparamagnetic behavior of the samples. The dielectric constant measured at 300 K in the frequency range of 600 Hz to 1 MHz showed an exponential decay with increasing frequency. It was observed that the particle size increased with an increase in digestion temperature while saturation magnetization (Ms) decreased. These particles are suitable to be used as Magnetic Resonance Imaging contrast agent. K e y w o r d s: spinel structures, zinc ferrites, coprecipitation, superparamagnetism, dielectric constant