Magnetic and electrical properties of In doped cobalt ferrite nanoparticles

Abstract

Nanoparticles of CoFe2O4 and CoIn0.15Fe1.85O4 ferrites were prepared by citrate gel route and characterized to understand their structural, electrical, and magnetic properties. X-ray diffraction and Raman spectroscopy were used to confirm the formation of single phase cubic spinel structure. The average grain sizes from the Scherrer formula were below 50 nm. Microstructural features were obtained by scanning electron microscope and compositional analysis by energy dispersive spectroscopy. The hysteresis curve shows enhancement in coercivity while reduction in saturation magnetization with the substitution of In3+ ions. Enhancement of coercivity is attributed to the transition from multidomain to single domain nature. Electrical properties, such as dc resistivity as a function of temperature and ac conductivity as a function of frequency and temperature were studied for both the samples. The activation energy derived from the Arrhenius equation was found to increase in the doped sample. The dielectric constant (ε′) and dielectric loss (tan δ) are also studied as a function of frequency and temperature. The variation of dielectric properties ε′, tan δ, and ac conductivity (σac) with frequency reveals that the dispersion is due to Maxwell–Wagner type of interfacial polarization in general and the hopping of charge between Fe2+ and Fe3+ as well as between Co2+ and Co3+ ions at B-sites. Magnetization and electrical property study showed its dominant dependence on the grain size.

Influence of calcination temperature on Cd0.3Co0.7Fe2O4 nanoparticles: Structural, thermal and magnetic properties

“…The enhancement of dielectric constants ε′ and ε″, the loss tangent tan δ, and the AC conductivity s ac have been reported [18][19][20]. In addition, the conductance properties of cadmium cobalt ferrite, and the catalytic decomposition of 2-propanol are also reported [21].…”

“…Furthermore, particles come into contact with each other and under favorable energetic conditions [13]. Detailed studies on CoFe 2 O 4 have been carried out by various research groups [14][15][16][17][18][19][20][21][22], but systematic studies on the electrical, magnetic, and thermal studies of nanosized CoFe 2 O 4 are limited. The substitution of other metals in cobalt ferrite has been proposed inorder to tailor the magnetic, electrical, and magnetomechanical properties [15,16].…”

Temperature dependent dielectric and magnetic properties of GdFe1−xNixO3 (0.0 ≤ x ≤ 0.3) orthoferrites

“…20 The observed increase in e 0 at higher temperatures for all compositions can be attributed to the fact that the charge hopping is a thermally activated process hence polarization enhances with increasing temperature. 21 Fig . 3 shows the temperature dependence of dielectric constant at the selected frequencies, it can be inferred that the rate of increase of dielectric constant varies in different temperature regimes.…”

Effect of Er doping on the structural and magnetic properties of cobalt-ferrite

“…This shift indicates that strain is induced in the lattice due to the presence of large size Er þ3 and the broadening is due to the smaller crystallite size. 16 Relative increase in intensities of modes corresponding to octahedral sites below 600 cm À1 suggests that the Er 3þ has higher preference for octahedral sites. The red shift values are tabulated in Table I.…”