Investigation on the structures and magnetic properties of carbon or nitrogen doped cobalt ferrite nanoparticles

Abstract

Carbon or nitrogen doped cobalt ferrite nanoparticles were synthesized in the air by a facile calcination process. X-ray diffraction, mapping, X-ray photoelectron spectroscopy, and mössbauer spectra results indicate that the nonmetal elements as the interstitial one are doped into cobalt ferrite nanoparticles. The morphologies of doped cobalt ferrite nanoparticles change from near-spherical to irregular cubelike shapes gradually with the increased carbon or nitrogen concentration, and their particles sizes also increase more than 200 nm. Furthermore, the saturation magnetization of carbon doped cobalt ferrite is improved. Although the saturation magnetization of N-doped cobalt ferrite is not enhanced obviously due to the involved hematite, they also do not drop drastically. The results reveal an approach to synthesize large scale ferrite nanoparticles, and improve the magnetic properties of ferrite nanoparticles, and also provide the potential candidates to synthesis co-doped functional magnetic materials.

Magnetic Texture in Insulating Single Crystal High Entropy Oxide Spinel Films

“…[24][25][26][27] To take advantage of this complex cation disorder, chemical doping is widely used to tune magnetic functionality in spinel ferrites. [28][29][30] However, previous studies show that incorporating multiple chemical dopants into the A-or Bsite in spinel ferrites can lead to quenched chemical mixing, which drives the creation of undesired secondary phases and poor surface morphologies which preclude epitaxial heterostructuring. [31][32][33] Given the complexity of the single phase formation in multi-cation doped-spinel ferrites where a random cation distribution can be used to tailor magnetic properties, synthesizing spinels which can be made to host a large number of different cations on the A-and/or B-sites without disrupting crystallinity or structural phase would be an exceptional tool towards designing MIs.…”

“…Magnetic insulators (MIs) are promising materials for spintronics, spincaloritronics, nonvolatile memories, and microwave applications. − The selection of MI heterostructures in a single-crystal thin film, grown on a suitable substrate, is critical for realizing quality interfaces for these applications. , However, excellent quality MI single-crystalline materials of a Curie temperature well above room temperature are rare. Ferrimagnetic insulating oxides with the AB 2 O 4 spinel structure have been widely studied for these applications because they offer interesting MI properties. ,− Within spinel oxides, there are three different structural motifs, normal, random, and inverse, which are distinguished based on the distribution of cations among the tetrahedral and octahedral sites. ,− In particular, inverse spinel ferrites (B = Fe) have received a great deal of interest as room-temperature MIs for the aforementioned applications. − The entropy change associated with the cation disordering in a spinel configuration has a major impact on the thermodynamic landscape required to stabilize these spinel structures. , Therefore, the cation disorder at tetrahedral and octahedral sites is a critical factor in determining the magnetic, optical, and transport properties. ,, The dependence of the configurational entropy on the degree of cation disorder has been reported in spinel ferrites as leading to variation in magnetic ground states. − To take advantage of this complex cation disorder, chemical doping is widely used to tune magnetic functionality in spinel ferrites. − However, previous studies show that incorporating multiple chemical dopants into the A - or B -site in spinel ferrites can lead to quenched chemical mixing, which drives the creation of undesired secondary phases and poor surface morphologies that preclude epitaxial heterostructuring. − Given the complexity of the single-phase formation in multi-cation-doped spinel ferrites, where a random cation distribution can be used to tailor the magnetic properties, synthesizing spinels that can be made to host a large number of different cations on the A - or B -sites without disrupting the crystall...…”

Properties, applications, and synthesis of first transition series substituted cobalt ferrite: a mini review

“…The structure and properties of CF-NPs materials can be modified by substitution/doping. They can be doped with metal ions [34], representative elements [35][36][37], transition metals [35,[38][39][40], rare earth [35], and non-metals [41]. CF-NPs have been doped with FTEs as they have of their comparable ionic size [35].…”

Magnetic Materials in Promoting Bone Regeneration

“…Magnetic particles and composites can be used for drug delivery (Amiri et al, 2019), imaging-based diagnosis of cancer (Belyanina et al, 2017) and non-invasive clinical measurements (e.g., measurement of Fe levels in the liver) (Avrin and Kumar, 2007). Scientists have focused on the synthesis of materials with magnetic effects and their biological performance (Tampieri et al, 2014;Cao et al, 2018;Patel et al, 2018). A great advantage of magnetic materials is that they can deliver biological "cues" without the need for contact with tissues.…”