Magnetic, electric and dielectric properties of FeCo alloy nanoparticles dispersed in amorphous matrix

Abstract

Nanocrystalline Fe 53 Co 47 alloy was synthesized by a singlestep transmetallation chemical method at room temperature. The Fe 53 Co 47 alloy nanoparticles of 77 and 47 wt% were dispersed in silica matrix by the sol-gel process using tetraethyl orthosilcate. Structural studies reveal that the as-prepared alloy powders are in bcc phase and silica is in an amorphous state. The phase-transition temperature and Mössbauer spectra analysis of the Fe-Co alloy establishes the homogeneous alloy formation. A saturation magnetization of 218 emu/g was obtained for pure FeCo alloy at room temperature. Scanning electron micro-scopic analysis demonstrates the hollow-sphere morphology for FeCo alloy particles. Magnetic nanocomposite consisting of 47 wt% FeCo-silica shows enhanced thermal stability over the native FeCo alloy. Electrical and dielectric properties of 47 wt% FeCo-silica nanocomposites were investigated as a function of frequency and temperature. It was found that the dielectric constants and dielectric loss were stable throughout the measured temperature (310-373 K). Our results indicate that FeCo-silica nanocomposite is a promising candidate for high-frequency applications.

Controlled Morphologies and Intrinsic Magnetic Properties of Chemically Synthesized Large-Grain FeCo Particles

“…Moreover, magnetic properties of FeCo alloys are deeply influenced by their microstructure such as grain size, morphology, and structure of FeCo phase in them. Recently, much attention has been focused on Fe-based magnetic nanoparticles due to their controllable structure, excellent magnetic properties, dielectric properties, and latent use in microwave absorption and biomedical applications [10][11][12][13][14]. Many works have been done to synthesize varieties of nano-sized FeCo alloys for compensating the limitation of traditional FeCo materials [15][16][17][18].…”

High-frequency magnetic properties of FeNi3–SiO2 nanocomposite synthesized by a facile chemical method

“…The highfrequency performance of these ferrites is limited by Snoek's law. Therefore, to meet these requirements, magnetic metal/insulator nanocomposites are frequently suggested to be used as materials for high-frequency applications [17][18][19]. By encapsulating magnetic metal nanoparticles with insulating phase, the resistivity of the materials can be dramatically increased.…”

Structure and magnetism of Fe–Co alloy nanoparticles

“…Various preparation methods, such as mechanical alloying [16], polyol [17,18,19] and solgel [20,21] process, transmetallation [22], coprecipitation [23], as well as co-reduction [24] with ultrasound assistance [25] have been reported to result in Fe-Co alloy nanoparticles with various Co concentration levels. Due to their large reactive specific surface area, fine metal powders can be susceptible to spontaneous ignition under exposure to air, and consequently they require special precautions regarding their storage and manipulations [26].…”