Cr³⁺ substituted aluminum cobalt ferrite nanoparticles: influence of cation distribution on structural and magnetic properties

Abstract

Nanoparticles Cr x Al 0.5-x CoFe 1.5 O 4 (x=0.1, 0.25 and 0.4) spinel ferrites were synthesized by coprecipitation technique, aiming to study the relationship between cation distribution of the substitution of chromium and aluminum ions on the structure, morphology, magnetic properties, permeability, Curie temperature and AC loss. X-ray diffraction (XRD) analysis used with Rietveld refinement revealed nanocrystalline single-phase of the spinel ferrites. The calculated average crystallite size is between 40 and 45 nm. The obtained results show, that both lattice constant and total porosity increased by increasing Cr 3+ concentration. It was found that Al 3+ occupied tetrahedral (A) and octahedral (B) sites whereas, Cr 3+ preferred to occupy only octahedral (B) sites. The magnetization M s, coercivity H c and the magneto-crystalline constant k 1 decreased with increasing Cr 3+ content. Likewise, Curie temperature T C decreased from 670 K to 585 K with increasing Cr 3+ concentration. Magnetic loss has further been observed and increased with increasing Cr 3+ concentration in all investigated samples.

Optimization of visible photoluminescence emission from Ni-Zn ferrite thin films

“…The fit goodness (S) is defined as the ratio between the weighted pattern (R wp ), and the expected values (R exp ) (S = R wp / R exp ). The refinement was maintained until a value of S close to one was found to be convergent, which validates the value of refinement [26][27][28]. The refinement parameters values as well as the lattice parameter and the crystallite size are shown in table 1, which suggests a rather good precision in synthesizing the spinel thin films without any additional phases.…”

Comparison of optical absorption and diffuse reflectance spectra techniques for determining the optical energy band gap of dried and calcined Ni0.5Mn0.5Fe2O4 nanoferrite

“…The peak of the (311) plane was used to calculate the particle sizes and the calculated crystallite size was listed in table 1. The lattice constants 'a' of the investigated dried (Powder 100) and calcined (Powder 600) of Ni 0.5 Mn 0.5 Fe 2 O 4 nanoparticles, were obtained from the following equation [8] and are listed in table 1,…”

“…Some of the phenomena discovered in nanoparticles of different ferrites include superparamagnetism, spin pining and canting, metastable cations distribution, and others. Several factors, such as particle shape and size, anisotropy, surface morphology, and interaction between particles is affected these [8][9][10][11]. Nickel and manganese ferrite nanoparticles, among other mixed transition metals, have been used as potential materials in multidisciplinary fields.…”

The Effect of Opto-Electronic Transition Type on the Electric Resistivity of Cr-Doped Co3O4 Thin Films

“…Transition metal oxide thin films have attracted physical properties, such as their chemical stability, tunning their electric and optical properties [4][5][6][7]. Cobalt oxide is known as a promising material due to its applications in many fields, such as CO gas sensors [8], solar absorbers at high temperatures [9], photocatalysts for dye degradation in water purification, and magnetic materials [10]. In the form of thin films, cobalt oxide is used as an electrode in super capacitor design and in the fabrication of electrochromic devices [11] as a result of changing its optical properties under an external electrical stimulus [12].…”

“…Furthermore, the method of preparation for Co 3 O 4 thin film has great effects on the magnetic, electric and optical properties of the prepared samples. These effects are attributed to the change in the crystallite size, morphology and texture of the prepared samples [10][11][12]. In particular, many techniques have been reported for the synthesis of Co 3 O 4 thin films, such as chemical vapor deposition [13,14] and chemical spray pyrolysis [16].…”