Structure-based magnetic, electrical and transport properties of Ni-Zn-Co ferrite by V5+ substitution br

This article presents the modification of structure-based magnetic, electronic and transport properties along with the conduction mechanism and its relaxation process in a Ni-Zn-Co ferrite tailored by V5+ substitution at B-site replacing Fe3+ ions. The composition Ni0.7Zn0.2Co0.1Fe2-xVxO4 (0< x<0.12) was synthesized by standard solidstate reaction method and all samples were crystallized with a single-phase cubic spinel structure belonging to the Fd((3) overbar) m space group. The lattice constants decreased gradually from 8.3673.A to 8.3602.A and the average grain sizes (D-SEM) are also decreased from 6.92 mu m to 1.99 mu m due to V5+ ions substitution at Fe3+ of B-site. However, more than 25% of Fe3+ ions migrate to A-site from B-site due to V5+ substitution at Fe3+ of B-site. In all samples theta(D) does not strictly follow the Anderson's prediction, rather it monotonically decreases to a low value until x = 0.12. Magnetic phase transition temperature shifted to the lower temperature and the net magnetization (eta(e)(B)) decreases due to V5+ substitution in Ni-Zn-Co ferrite. Apart this, during conduction charge carriers should require more energy to jump from one cationic site to other for V5+ substitution in the Ni-Zn-Co ferrite and the activation energy (E-a) is much more higher in V5+ substituted sample. Moreover, long-range interaction with localized relaxation mechanism is observed in V5+ doped samples. The resistance at the grain (R-g) is maximum (243.09 Omega) for the sample x = 0.10 while grain boundary resistance (R-gb) is maximum (5.98x10(5) Omega) for the sample x = 0.07. However, the higher value of rho(dC) for x = 0.12 sample ensures to be suitable for electromagnets, transformers, electronic inductors, and at high-frequency applications. Moreover, x = 0.07 sample displays high value of TCR ( 8.6%/K at 418 K) which may be utilized as an infrared detector for night vision bolometer material.