Size dependent magnetic and dielectric properties of nano CoFe2O4 prepared by a salt assisted gel-combustion method

作者：Vasundhara K^*; Achary S N; Deshpande S K; Babu P D; Meena S S; Tyagi A K

来源：Journal of Applied Physics, 2013, 113(19): 194101.

DOI：10.1063/1.4804946

In this communication, we report the preparation and properties of nano-CoFe2O4 by gel combustion in presence of KCl and subsequent heat treatments. The products were characterized by X-ray diffraction, Infrared spectroscopy, and Mossbauer Spectroscopy. Spinel type structure with all Fe in 3+ oxidation states was confirmed from the XRD and Mossbauer spectroscopy. The average crystallite sizes of the studied samples were about 6 and 50nm. Low temperature magnetic and dielectric properties of the samples were studied by superconducting quantum interference device magnetometry and ac-impedance spectroscopy. The field and temperature dependent magnetization studies indicated superparamagnetic nature for 6 nm sample and ferromagnetic nature for 50nm sample. The temperature-dependent dielectric properties measured over a wide range of frequencies indicated an increasing trend of dielectric permittivity with the decrease in crystallite size. Variable range polaron hopping conduction was observed in both samples.

• 出版日期2013-5-21