Influence of Particle Size on the Electrical Properties and Magnetic Field Dependent I–V Characteristics of Nanocrystalline ZnFe₂O₄

ABSTRACT

The influence of grain size (7-16 nm) on electrical conductivity, dielectric properties and magnetic field dependent I–V characteristics along with magnetoresistance have been studied for zinc ferrite ( ZnFe ₂O₄). ZnFe₂O₄ was prepared by co-precipitation technique. Ball milling on the chemical routed material was carried out to control the particle size. The effect of particle size on the conduction mechanism was investigated by nonlinear least-squares fitting of the impedance spectrum. The electrical response was found to be strongly influenced by the particle size of the material. Electrical conductivity decreased with decrease of particle size. Electrical conductivity (σ) significantly changed with temperature indicating thermal activated conductivity mechanism. I–V characteristics of the material showed variation of resistance with magnetic field, indicating existence of magnetoresistance (MR). The exhibition of I–V loops confirmed the existence of two irreversible electronic states (bi-stable states: LRS and HRS) in the material, which helped to extract information about non-volatile electronic states and electrical power loss (loop area) in presence of magnetic field. The I–V loop repetition for 20 times within bias voltage range ±20 V gave the information about the stability of the current variation with bias voltage.

GRAPHICAL ABSTRACT

Keywords:

• Zinc ferrite nanocrystals
• I–V characteristics
• Magnetoresistance
• Bi-stable electronic states