Impact of La^(3+)substitution on electrical,magnetic,dielectric and optical properties of Ni_(0.7)Cu_(0.1)Zn_(0.2)LaxFe_(2-x)O_(4)(0<x<0.035)system

The oxalate co-precipitation method was used to synthesize the La3+substituted Ni-Cu-Zn(La-NCZ)nanoferrites having chemical composition Ni_(0.7)Cu_(0.1)Zn_(0.2)LaxFe_(2-x)O_(4)(x=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 La^(3+)content.In the temperature range of 30-170℃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’andμ")parts are attributed to the domain wall movement and magnetic spin resonant.Theμi,u’andμ"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 thatε’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.