Magnetic, transport and electronic properties of Ni$_2$FeAl Heusler alloy nanoparticles: Experimental and theoretical investigation

TL;DR

This study investigates Ni$_2$FeAl Heusler alloy nanoparticles, revealing their magnetic, transport, and electronic properties through experimental synthesis and theoretical calculations, highlighting their potential for technological applications.

Contribution

It provides a comprehensive experimental and theoretical analysis of Ni$_2$FeAl nanoparticles, including magnetic anisotropy, Curie temperature, and electron interactions, which were not previously detailed.

Findings

High saturation magnetization of 3.02 μ_B/f.u. at 5 K

Large magnetic anisotropy of 0.238 MJ/m^3

Curie temperature of 874 K

Abstract

We present a comprehensive investigation of structural, magnetic and transport properties of Ni$_2$FeAl Heusler alloy nanoparticles (NPs) synthesized via template-less chemical route. The NPs exhibit high saturation magnetization of 3.02 $\mu_ {\rm B}$/f.u. at 5~K, large magnetic anisotropy of 0.238 MJ/m$^3$, and a Curie temperature of 874~K. Magnetocaloric analysis reveals a magnetic entropy change of 3.1 J.kg$^{-1}$K$^{-1}$ at 70 kOe. Low-temperature transport measurements show a weak resistivity upturn, following a $-T^{1/2}$ dependence, indicative of disorder-enhanced electron-electron interactions. First-principles calculations based on density functional theory yield a magneto-crystalline anisotropy energy of 0.987 MJ/m$^3$, consistent with experiment and demonstrate pronounced surface and finite-size effects through comparison of bulk and nanocluster geometries. The combination of high Curie temperature, sizable perpendicular magnetic anisotropy, and moderate spin polarization and magnetic entropy change make the Ni$_2$FeAl as promising candidate for various applications.