Effect of B-site Co substitution on the structure and magnetic properties of nanocrystalline neodymium orthoferrite synthesized by auto-combustion

Abstract

Samples of cobalt-doped neodymium orthoferrite compounds, NdCo x Fe 1−x O 3 (0.0 ≤ x ≤ 0.5) were synthesized via glycine auto-combustion between 250 and 300°C and calcined at 500°C for 2 h. X-ray diffraction showed that all compounds had an orthorhombic perovskite structure with space group Pbnm. Increasing cobalt doping gradually reduced the lattice parameters and contracted the unit cell volume. Both X-ray diffraction and scanning electron microscopy showed that the particles were spherical and in the nano-sized range (19–52 nm) with pores between grains. Vibrating sample magnetometry at room temperature indicated that NdFeO 3 has a high coercive field (1950 Oe) and cobalt substitution for iron led to a decrease in the coercive field, saturation and remanent magnetization, which was as a result of decreased magnetic moments in the crystal and reduced canting of the FeO 6 octahedra. The increase in magnetization and coercive fields with increase of Co was connected to the microstructure (bond lengths and angles, defects, pores, grain boundaries) and crystallite size. The compounds NdCo x Fe 1−x O 3 show antiferromagnetism with weak ferromagnetism due to uncompensated non-collinear moments. These compounds could serve as prototypes for tuning the properties of magnetic materials (ferromagnetic and antiferromagnetic) with potential applications in data storage, logic gates, switches and sensors.

Synthesis and Mechanism of Co2+/Sr2+ Codoped Magnetic Lanthanum Cuprate with Excellent Corrosion Resistance

“…The substitution of smaller La 3+ by larger Sr 2+ caused growth of the cell along the c axis. The introduction of Co 2+ decreased the volume of the unit cell, which was consistent with the literature. − …”

Optical and Photocatalytic Properties of Cobalt-Doped LuFeO3 Powders Prepared by Oxalic Acid Assistance

“…Since the ionic radius of Co 3+ (54.5 pm in LS and 61.0 pm in HS) is slightly less than that of Fe 3+ (64.5 pm in HS), shrinkage is expected, indicating a successful substitution of Co ions at Fe sites [17,36,37]. Similar results have also been reported for NdFe 1−x Co x O 3 systems [24][25][26]. In order to explore the effect of Co doping on the fine structure of the parent LFO, we performed FTIR spectroscopy, an analytical technique capable of revealing the nature of structures by detecting lattice vibrations.…”

“…Recently, researchers have carried out extensive investigations on the structure, morphology, and electrical, optical, and magnetic properties of B-site cobalt-doped orthorhombic RFeO 3 . Most research focuses on orthorhombic NdFeO 3 [24][25][26][27][28], YbFeO 3 [29], DyFeO 3 [30], and LaFeO 3 [31]. It has been found that these Co-doped RFeO 3 systems show considerable enhancement in their physical properties compared to their parent counterparts.…”

Single-Domain Hard Ferromagnetic M-SrFe Nanoparticles for Magnetic Data Storage

“…Hexaferrite exhibits magnetic properties and it can be used in recording devices and in permanent magnetic materials [21]. SrFe nanoparticles have potential magnetic applications in magnetic storage, logic, and data storage [42].…”

“…TG-DTA graph of M-SrFe Nps 5.489 mg of the sample underwent the experimental analysis, which was conducted while it was being heated at a temperature of 20 0 C per minute in an air medium. The temperature range is between 30 0 C and 1200 0 C. The weight loss of 1.84% begins at temperatures between 300 0 C and 122 0 C. This is due to the partial vaporization of the compound[47]. The weight loss of 1.8% occurs at 460 0 C due to the formation of Fe2O3[48].…”