Magnetic and dielectric properties of rare earth substituted Ni0.5Zn0.5Fe1.95R0.05O4 (R = Pr, Sm and La) ferrite nanoparticles

•Formation of pure phase rare earth substituted nanocrystalline Ni0.5Zn0.5R0.05Fe1.95O4 (R = La, Pr and Sm) using citrate precursor method and at low annealing temperature of 450 °C.•Systematic changes in the lattice parameters with particle size and significant changes in magnetic parameters in the rare-earth substituted nanoferrites.•Large ionic radii of rare earth ions triggering local distortion and inducing softening of super exchange interaction. Decreasing order of coercivity and magnetization due to less number of domain walls and its movement in the direction of the magnetic field.•Dielectric measurements at higher frequency range (100 Hz–1 MHz) shows that these substituted ferrites exhibit small dielectric loss, which is suitable for high frequency applications.

Ni0.5Zn0.5Fe1.95R0.05O4 nanoparticles (R = Pr, Sm and La) have been synthesized by citrate precursor method and annealed at 450 °C. All the samples were found to be in single phase. The lattice constants and crystallite size decreases with rare earth substitution (25 nm, 23 nm, 11 nm and 9 nm) due to strain produced in spinel lattice. Saturation magnetization and coercivity of ferrite significantly decreases (50.69 emu/g, 32.17 emu/g. 30.21 emu/g and 34.65 emu/g respectively) with rare earth substitution. The substitution of large ionic radius rare earth ions in Ni0.5Zn0.5Fe2O4 results in distortion and induces a softening of magnetic exchange interaction. The dielectric measurements at higher frequency range (100 Hz–1 MHz) shows that these substituted ferrites exhibits low dielectric loss, which is suitable for high frequency applications.