Effect of sintering temperature on the structural, morphological, electrical, and magnetic properties of Ni–Cu–Zn and Ni–Cu–Zn–Sc ferrites Md. Harun-Or-Rashid 1, * , M. Nazrul Islam 2 , M. Arifuzzaman 3 , and A. K. M. Akther Hossain 4 1 Department of Physics, Bangladesh University of Textiles, Dhaka 1208, Bangladesh 2 Faculty of Science and Humanities, Bangladesh Army International University of Science and Technology, Cumilla 3501, Bangladesh 3 Department of Mathematics and Physics, North South University, Dhaka 1229, Bangladesh 4 Department of Physics, Bangladesh University of Engineering and Technology, Dhaka 1000, Bangladesh Received: 30 May 2020 Accepted: 1 December 2020 Published online: 2 January 2021 Ó The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature 2021 ABSTRACT Polycrystalline Ni 0.3 Cu 0.2 Zn 0.5 Fe 2 O 4 and Ni 0.3 Cu 0.2 Zn 0.5 Sc 0.05 Fe 1.95 O 4 com- pounds have been prepared by standard solid-state reaction technique and sintered at 1000, 1100, 1150, 1200, and 1250 °C for 5 h in air. The effect of sin- tering temperature on the structural, morphological, magnetic, dielectric, and electrical properties of these spinel ferrites has been studied thoroughly and comparatively. Formation of the single-phase cubic spinel structure of these compositions is confirmed by X-ray diffraction analysis. The lattice constant increases with sintering temperature as well as with 5% scandium (Sc 3? ) doping in Ni–Cu–Zn ferrite. Surface morphology reveals that the grain size increases with sintering temperature. Among the prepared ferrites, Ni 0.3 Cu 0.2 Zn 0.5 Sc 0.05- Fe 1.95 O 4 has the maximum density (5.05 9 10 3 kg/m 3 ) at sintering temperature 1150 °C, which gives the highest value of initial permeability. It is observed that initial permeability varies with sintering temperature, and it gives the maximum value at optimum sintering temperature. It is noted that Curie temperature decreases with 5% Sc 3? ions doping, whereas it slightly increases with increasing sintering temperature for both compositions. Ni 0.3 Cu 0.2 Zn 0.5 Fe 2 O 4 compound shows the highest Curie temperature 418 °C. Dielectric constant, dielectric loss factor and AC electrical conductivity decrease with 5% Sc 3? ions doping in Ni–Cu–Zn ferrite. The initial permeability decreases sharply at Curie temperature, which indicates a high degree of compositional homogeneity. The ‘Hopkinson’ peak is observed just below the Curie temperature in the real part of initial permeability versus temperature graphs. The mechanism of dielectric polarization and electrical conductivity has been explained based on the elec- tron hopping between Fe 3? and Fe 2? ions. The variation trend of complex Address correspondence to E-mail: h_o_rashid@butex.edu.bd https://doi.org/10.1007/s10854-020-05018-7 J Mater Sci: Mater Electron (2021) 32:2505–2523 Content courtesy of Springer Nature, terms of use apply. Rights reserved.