Effect of Ho³⁺substitution on the cation distribution, crystal structure and magnetocrystalline anisotropy of nanocrystalline cobalt ferrite

Abstract

Ho 3þ ion-substituted nanocrystalline cobalt ferrite materials with the chemical formula CoFe 2Àx Ho x O 4 for x ¼ 0.0, 0.025, 0.05, 0.075 and 0.1 have been synthesised by standard citrate precursor method. Crystal structure and phase purity have been studied by powder X-ray diffraction (XRD) method by employing Rietveld refinement technique. The distribution of cations between the tetrahedral site (A-site) and octahedral site (B-site) has been estimated by Rietveld analysis. The refinement result shows that Ho 3þ ion has a strong preference for octahedral sites (B-sites). The lattice constants decrease with the Ho 3þ concentration up to x ¼ 0.05. Crystallite size decreases with the Ho 3þ concentration. The magnetic hysteresis loop measurements have been carried out at room temperature using a vibrating sample magnetometer (VSM) over a field range of AE2 T. The magnetisations in saturation have been analysed by employing the 'law of approach (LA)' technique. The magnetocrystalline anisotropy constant and saturation magnetisation are found to decrease with the Ho 3þ concentration up to x ¼ 0.05. The coercivity decreases with the Ho 3þ concentration. The vibrational modes of the octahedral and tetrahedral metal complex in the sample have been carried out using Fourier transform infrared spectroscopy (FT-IR). The FT-IR spectra of the samples have been analysed in the wave number range of 350-1000 cm À1 . We have observed two prominent absorption bands which are assigned to tetrahedral and octahedral metal complexes. The elemental analysis has been carried out using energy dispersive spectroscopy (EDS) with the help of field emission scanning electron microscope (FE-SEM) and the results reveal that, elements are as per the stoichiometric ratio in all the samples.

Metal to semimetal transition and magnetic critical behavior at room temperature in the full Heusler alloy Fe2MnSi

“…The modified LA to saturation magnetization is presented by the following equation as applicable for a polycrystalline sample in a field greater than the 1T field region [36,37].…”

The correlation between structure and magneto optical properties of nanostructured Magnesium ferrites upon Molybdenum doping for magnetic and optoelectronic applicability

“…Nano-ferrites have endless attract due to its exclusive performance of structure, electric, magnetic, optical properties as well as their capability technological applications in multidisciplinary fields such as magnetic resonance imaging [1], high density memory devices [2,3], carriers for drug targeting [4], electrical properties [5] radiation shielding and opto-electronic properties [6][7][8][9]. Ferrites are classified based on their lattice constructions, which include spinel, orthogonal, and hexagonal ferrites, or their magnetic properties, which include delicate and hard ferrites.…”

Diffusion-controlled growth of CuAl2O4 nanoparticles: effect of sintering and photodegradation of methyl orange

“…[5À8] They also CONTACT Suresh D. Kulkarni suresh.dk@manipal.edu find a wide range of applications in magnetic materials, [9,10] paints, pigments, [11,12] refractory materials, [13] cements, [14] [32] In the current study, we propose the formation of single-phase CuAl 2 O 4 spinel through a diffusion process involving an immobile Al 2 O 3 matrix and investigate the effects of temperature on this diffusion mechanism.…”