Large magnetoresistance in carbon-coated Ni/NiO nanoparticles

Bulletin of Materials Science

SUBIR ROY^1¹ 

[1]Centre for Nano and Soft Matter Sciences (CeNS), Jalahalli, Bangalore 560013, India^1

关键词: Magnetoresistance;    exchange bias;    nanoparticles.;   

DOI  :  

学科分类：材料工程

来源: Indian Academy of Sciences

【 摘 要 】

We report here a large magnetoresistance (MR) observed in carbon-coated Ni/NiO nanostructures synthesize by a chemical method. The crystalline nature and particle size of the graphitic-carbon-coated Ni/NiO nanostructure wasinvestigated by X-ray diffraction study and field emission scanning electron microscope images. The Raman spectroscopy confirms the presence of graphite layer over the Ni/NiO nanostructure. The field-cooled (FC) magnetic hysteresis curves show exchange bias effect suggesting possible Ni/NiO core–shell structure. The temperature-dependent magnetization data show bifurcation in FC–zero-field-cooled curves, indicating the superparamagnetic behaviour and competing ferromagnetic (FM) and antiferromagnetic interactions in the nanocomposite. MR studies show a large negative MR of $\sim$20% at 18 K and$\sim$4.2% at room temperature, revealing significant enhancement of FM interactions at low temperatures and spin-dependent tunnelling of current through the nanocomposite.

【 授权许可】

CC BY