Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userThe structural and magnetic properties of (In1-xFex)2O3 (0.0 <= x <= 0.25) system : prepared by gel combustion method
128
0
0.0
(
0
)
Added by
I.K. Gopalakrishnan
Publication date
2007
fields
Physics
and research's language is
English
Ask ChatGPT about the research
No Arabic abstract
(In1-xFex)2O3 polycrystalline samples with x = (0.0, 0.05, 0.10, 0.15, 0.20 and 0.25) have been synthesized by a gel combustion method. Reitveld refinement analysis of X raydiffraction data indicated the formation of single phase cubic bixbyite structure without any parasitic phases. This observation is further confirmed by high resolution transmission electron microscopy (HRTEM) imaging, and indexing of the selected-area electron diffraction (SAED) patterns, X-ray Absorption Spectroscopy (XAS) and Raman Spectroscopy. DC Magnetization studies as a function of temperature and field indicatethat they are ferromagnetic with Curie temperature (TC) well above room temperature.
rate research
Read More
Manganese ferrite (MnFe2O4) and copper doped manganese ferrite (Mn0.75Cu0.25Fe2O4) soft materials were synthesized through solid-state sintering method. The phase purity and quality were confirmed from x-ray diffraction patterns. Then the samples were subjected to neutron diffraction experiment and the diffraction data were analyzed using FullProf software package. The surface morphology of the soft material samples was studied using a scanning electron microscope (SEM). Crystal parameters, crystallite parameters, occupancy at A and B sites of the spinel structure, magnetic moments of the atoms at various locations, symmetries, oxygen position parameters, bond lengths etc. were measured and compared with the reference data. In MnFe2O4, both octahedral (A) and tetrahedral (B) positions are shared by Mn2+ and Fe2+/3+ cations, here A site is predominantly occupied by Fe2+ and B site is occupied by Mn at 0.825 occupancy. The Cu2+ ions in Cu0.25Mn0.75Fe2O4 mostly occupy the B site. Copper mostly occupy the Octahedral (16d) sites. The length of the cubic lattice decreases with the increasing Copper content. The magnetic properties, i.e. A or B site magnetic moments, net magnetic moment etc. were measured using neutron diffraction analysis and compared with the bulk magnetic properties measured with VSM studies.
Single-domain particles of SrFe8Al4O19 were prepared by thermal treatment at 1473 K of porous products of citrate-nitrate auto-combustion, and the influence of synthesis time on the particle morphology and magnetic properties was studied. The procedure allows to obtain SrFe8Al4O19 particles with mean diameters 100 - 460 nm, and their coercivity ranges from 14.5 to 18.4 kOe, while ferromagnetic resonance frequencies vary from 149 to 164 GHz.
Perovskite manganite La0.5Ca0.5-x xMnO3 (LCMO) nanomaterials were elaborated using the sucrose modified auto combustion method. Rietveld refinements of the X-ray diffraction patterns of the crystalline structure confirm a single-phase orthorhombic state with Pbnm space group (No. 62). The Ca-vacancies were voluntarily created in the LCMO structure in order to study their influence on the magnetic behaviour in the system. The magnetic susceptibility was found to be highly enhanced in the sample with Ca-vacancies. Paramagnetic-to-ferromagnetic phase transition was evidenced in both samples around 254 K. This transition is, characterized by a drastic jump of the susceptibility in the sample with Ca-vacancies. The maximum of entropy change, observed for both compounds at magnetic field of 6T was 2.30 J kg-1K-1 and 2.70 J kg-1K-1 for the parent compound and the lacunar one respectively. The magnetocaloric adiabatic temperature change value calculated by indirect method was 5.6 K and 5.2 K for the non-lacunar and Ca-vacancy compound, respectively. The Ca-lacunar La0.5Ca0.5-x xMnO3 (x=0.05) reported in this work demonstrated overall enhancement of the magnetocaloric effect over the LCMO. The technique used to elaborate LCMO materials was beneficial to enhance the magnetocaloric effect and magnetic behaviour. Therefore, we conclude that this less costly environmentally friendly system can be considered as more advantageous candidate for magnetic refrigeration applications then the commonly Gd-based compounds.
Epitaxial LaRh1/2Mn1/2O3 thin films have been grown on (001)-oriented LaAlO3 and SrTiO3 substrates using pulsed laser deposition. The optimized thin film samples are semiconducting and ferromagnetic with a Curie temperature close to 100 K, a coercive field of 1200 Oe, and a saturation magnetization of 1.7muB per formula unit. The surface texture, structural, electrical, and magnetic properties of the LaRh1/2Mn1/2O3 films was examined as a function of the oxygen concentration during deposition. While an elevated oxygen concentration yields thin films with optimal magnetic properties, slightly lower oxygen concentrations result in films with improved texture and crystallinity.
FeGa3 is a well known d-p hybridization induced intermetallic bandgap semiconductor. In this work, we present the experimental and theoretical results on the effect of Al substitution in FeGa3, obtained by x-ray diffraction (XRD), temperature dependent resistance measurement, room temperature Mossbauer measurements and density functional theory based electronic structure calculations. It is observed that upto x = 0.178 in Fe(AlxGa1-x)3, which is the maximum range studied in this work, Al substitution reduces the lattice parameters a and c preserving the parent tetragonal P42/mnm crystal structure of FeGa3. The bandgap of Fe(AlxGa1-x)3 for x = 0.178 is reduced by ~ 24% as compared to FeGa3. Rietveld refinement of the XRD data shows that the Al atoms replace Ga atoms located at the 8j sites in FeGa3. A comparison of the trends of the lattice parameters and energy bandgap observed in the calculations and the experiments also confirms that Al primarily replaces the Ga atoms in the 8j site.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
