Search

In this work, the structural and magnetic properties of multiferroic La 1 - x Y x FeO 3 perovskites, (x = 0.00, 0.05, 0.10, 0.15, 0.20, 0.25 and 0.30) synthesized through Sol-gel auto-combustion technique were investigated.The room temperature synchrotron X-ray diffraction (XRD) analysis revealed that the all the synthesized samples consisted of the polycrystalline orthorhombic structure perovskites (space group pnma), and tolerance factor confirmed the phase stability of the prepared perovskite system.The Williamson-Hall plots based on synchrotron XRD data were employed to estimate the average particle diameter and vary from 18.8 nm to 37.5 nm.For a deeper insight into the crystal structure, high-resolution transmission microscopy imaging (HRTEM) was performed.The estimated values of crystallite size from HRTEM and synchrotron XRD data were coincident.Many of crystallographic parameters and electron density measurements were calculated by Rietveld refinement of synchrotron XRD data. La 1 - x Y x FeO 3 perovskite crystals are canted antiferromagnets with a weak ferromagnetism at room temperature.Selected Area Electron Diffraction (SAED) patterns of the investigated samples exhibited spotty ring patterns, confirming the polycrystalline character.The magnetic properties were gotten through analyzing the magnetization versus temperature M(T) and M(H) hysteresis loop which characterized by a vibrating sample magnetometer (VSM). The orthoferrite La 1 - x Y x FeO 3 crystals are a promising candidate for optical device applications in broad temperature range and high power system.

Superparamagnetic iron oxide nanoparticles (SPION) Fe3O4 nanoparticles were prepared using different approaches: co-precipitation and sonochemical methods. This article is a comparative study on how different synthesis techniques greatly affect the magnetic properties and heating efficiency of such nanomaterial. Another important issue addressed here is the correlation between microstructure, colloidal stability, magnetization and specific absorption rate (SAR) of the nanoparticles. The results reveal that the sonochemical method for polyethylene glycol (PEGylated) Fe3O4 with size 5 nm leads to pseudo single domain with smallest loop area. Additionally, large SAR values are obtained within 10–15 min using low magnetic field.

The structural and magnetic properties of the spinel ferrite system Co 1+ x Fe 2−2 x Sn x O 4 ( x =0.0–1.0) have been studied. Samples in the series were prepared by the ceramic technique. The structural and microstructural evolutions of the nanophase have been studied using X-ray powder diffraction and the Rietveld method. The refinement result showed that the type of the cationic distribution over the tetrahedral and octahedral sites in the nanocrystalline lattice is partially an inverse spinel. Far infrared absorption spectra show two significant absorption bands, around 600 cm −1 and 425 cm −1 , which are respectively attributed to tetrahedral (A) and octahedral [B] vibrations of the spinel. Scanning Electron Microscopy (SEM) was used to study surface morphology. SEM images reveal particles in the nanosize range. The transmission electronic microscope (TEM) reveals that the grains are spherical in shape. TEM analysis confirmed the X-ray results. The magnetic properties of the prepared samples were characterized by using a vibrating sample magnetometer.

Nanocrystalline cobalt ferrite has been synthesized using two different methods: ceramic and co-precipitation techniques. The nanocrystalline ferrite phase has been formed after 3 h of sintering at 1000 °C. The structural and microstructural evolutions of the nanophase have been studied using X-ray powder diffraction and the Rietveld method. The refinement result showed that the type of the cationic distribution over the tetrahedral and octahedral sites in the nanocrystalline lattice is partially an inverse spinel. The transmission electronic microscope analysis confirmed the X-ray results. The magnetic properties of the samples were characterized using a vibrating sample magnetometer.