Surface magnetic states of Ni nanochains modified by using different organic surfactants

TL;DR

This study investigates how different organic surfactants modify the surface magnetic states of Ni nanochains, revealing surface-induced magnetic suppression and core-shell structures with potential implications for magnetic nanomaterials.

Contribution

It introduces a method to synthesize Ni nanochains with distinct surface magnetic states using various organic surfactants, highlighting the influence of surface layers on magnetic properties.

Findings

Surface magnetic states vary with surfactant type.

Suppression of saturation magnetization linked to surface states.

Core-shell structures with different magnetic surface layers.

Abstract

Three powder samples of Ni nanochains formed of polycrystalline Ni nanoparticles with an estimated diameter of about 30 nm have been synthesized by a wet chemical method using different organic surfactants. These samples, having magnetically/structurally core-shell structures, all with a ferromagnetic Ni core, are Ni@Ni3C nanochains, Ni@NiSG nanochains with a spin glass (SG) surface layer, and Ni@NiNM nanochains with a nonmagnetic (NM) surface layer. The average thickness of the shell for these three samples is determined as about 2 nm. Magnetic properties tailored by the different surface magnetism are studied. In particular, suppression in saturation magnetization usually observed with magnetic nanoparticles is revealed to arise from the surface magnetic states with the present samples.