Impact of La3+ substitution on electrical, magnetic, dielectric and optical properties of Ni0.7Cu0.1Zn0.2LaxFe2–xO4 (0

Abstract

The oxalate co-precipitation method was used to synthesize the La3+ substituted Ni–Cu–Zn (La–NCZ) nanoferrites having chemical composition Ni0.7Cu0.1Zn0.2LaxFe2–xO4 (x = 0, 0.015, 0.025 and 0.035). DC resistivity study of nanoferrites shows both the conducting and semiconducting behaviour. The room temperature DC electrical resistivity of Ni–Cu–Zn (NCZ) nanoferrites decreases, whereas Curie temperature increases with increasing La3+ content. In the temperature range of 30–170 °C nanoferrites show p-type semiconducting behavior except x = 0.015; thereafter, they show n-type behaviour. The frequency dispersive initial permeability (μi) associated with its real and imaginary (μ′ and μ") parts are attributed to the domain wall movement and magnetic spin resonant. The μi, μ′ and μ" of La–NCZ nanoferrites are higher than those of pure NCZ nanoferrite. Dielectric constant (ε′), dielectric loss (ε″) and AC resistivity (ρAC) of La–NCZ nanoferrites show normal dielectric behaviour. It is found that ε′ of NCZ nanoferrites decreases with the increasing content of La3+ ions. The bandgap energy of La–NCZ nanoferrites is achieved in the range 1.36–1.70 eV confirming the semiconducting nature of materials.