Articles you may be interested inThermal effect on magnetic parameters of high-coercivity cobalt ferrite J. Appl. Phys. 116, 033901 (2014); 10.1063/1.4890033Structural and ambient/sub-ambient temperature magnetic properties of Er-substituted cobalt-ferrites synthesized by sol-gel assisted auto-combustion method Variations in conductivity with particle size have been observed in cobalt ferrite, when synthesized by solgel auto-combustion method. Impedance analysis reveals metallic and semiconducting behavior at room temperature for a particle size of 6 nm and 52 nm, respectively. Upon thermal activation, metallic to semiconducting phase transition has been observed as a function of particle size and vice-versa. Grainboundary Resistance (R gb ), increased drastically with particle size (19 MX for 6 nm and 259 MX for 52 nm) at room temperature. AC conductivity and dielectric constants exhibit similar metallic to semiconducting phase transition at 6 nm and semiconducting behavior at 52 nm with temperature in the selected frequencies. Enhanced magnetic moment with an increase in the grain size along with decreased coercivity (1444 G to 1146 G) reveals transition from single domain to multi-domain. Increased inter-particle interaction is responsible for metallicity at the nano level and on the contrary semiconductivity is attributed to bulk. V C 2013 AIP Publishing LLC. [http://dx.

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