Resistance fluctuations and 1/f noise in single crystalline Ni nanowires

TL;DR

This study investigates resistance fluctuations and 1/f noise in single crystalline Ni nanowires, revealing magnetic contributions linked to thermally activated domain wall fluctuations affecting low-frequency noise.

Contribution

It provides new insights into magnetic-origin noise in ferromagnetic nanowires and links resistance fluctuations to domain wall dynamics.

Findings

1/f noise is partly magnetic in origin.

Magnetic noise decreases with increasing magnetic field.

Resistance fluctuations are influenced by thermally activated domain walls.

Abstract

We measured the low frequency (10mHz < f < 10Hz) resistance fluctuations (Noise) in single crystalline ferromagnetic Ni nanowires (diameter ~35nm) in the temperature range 80K-300K. The noise spectral power shows 1/f dependence. The nanowires in an applied magnetic field show negative magetoresistance that saturates for H <= HC. The noise spectral power shows a reduction in low applied field and becomes field independent for H >= HC. This indicates that a part of the observed 1/f noise arises from magnetic origin. The magnetic part is associated with thermally activated domain wall fluctuations that couples to the resistance fluctuations.