Size-Dependent Structural and Magnetic Properties of Disordered Co2FeAl Heusler Alloy Nanoparticles

TL;DR

This study investigates how reducing the size of Co2FeAl nanoparticles enhances their magnetic properties, revealing size-dependent structural and magnetic changes compared to bulk material.

Contribution

It provides new insights into size-dependent magnetic behavior of disordered Co2FeAl nanoparticles synthesized via chemical methods.

Findings

Smaller nanoparticles exhibit higher saturation magnetization.

Decreased particle size increases Curie temperature.

All samples are single-phase disordered (A2-type) structures.

Abstract

Co2FeAl (CFA) nanoparticles (NPs) of different sizes were synthesized by chemical route. The effect of the size of NPs upon the structure and magnetization compared to its bulk counterpart was investigated. The structure and composition were determined from X-ray diffraction (XRD) and electron microscopy. XRD analysis shows that the samples are having single (A2-type) disordered phase. Magnetization measurements suggest that the samples are soft ferromagnetic in nature with very low coercivity. Enhanced magnetic properties like saturation magnetization, coercive force, retentivity, and Curie-temperature are observed with a decrease in particle size. The effect of particle size on hysteresis losses is also discussed. The smallest particles of size 16 nm exhibited the highest saturation magnetization and transition temperature of 180.73 emu/g and 1261 K, respectively. The origin of enhancement in the magnetization of Co2FeAl nano-alloy is attributed to the strong Co-Co exchange interaction due to disorder present in the systems.