Understanding of intriguing metal to semiconductor transition in Ni0.5Zn0.5Fe2O4 nanoparticulates

¹Department of Physics, Harivandna College, Munjka, Rajkot 360005, India

²Department of Civil Engineering, Government Engineering College, Rajkot 360007, India

³Departmnet of Physics, Saurashtra University, Rajkot 360005, India

Adv. Mater. Lett., 2021, 12 (3), 21031614

DOI: 10.5185/amlett.2021.031614

Publication Date (Web): Jan 06, 2021

Copyright © IAAM-VBRI Press

E-mail: kunalbmodi2003@yahoo.com

Abstract

Temperature-dependent electrical transport characteristics of un-milled and high-energy ball-milled  samples (3 h (70 nm), 6 h (55 nm) and 9 h (45 mm)) of Ni_0.5Zn_0.5Fe₂O₄ spinel ferrite were explored. A well-defined metal to semiconductor transition exhibited by all the samples has been construed in view of direct and superexchange cationic interactions and delocalization to localization of charge carriers on increasing temperature. The peak temperature (T_max) was found to shift towards a higher temperature side on milling principally governs by the lattice vibration scattering and intrinsic excitation. The crystallite size reduction, enhancement in strain and sudden decrease in the formation and octahedral site occupancy of Fe²⁺ ions on milling found responsible for the prodigious rise (~ 250 times) in normalized resistivity values for the sample comminuted for 9 h. The spectrum of energies corresponds to charge trapping centers that cause small bump (3 h milled sample) and sharp cusp (9 h milled sample) for T>T_max. These materials may be found suitable for thermal cutoff switching applications.

Keywords

Spinel ferrite, mechanical milling, nanoparticles, electrical property, metal to semiconductor transition, cationic interactions, structural and microstructural parameters.