Affiliations: [a] Wolfson Centre for Magnetics, Institute of Energy,
Cardiff School of Engineering, Cardiff University, Cardiff, UK
Correspondence:
[*]
Corresponding author: Nkwachukwu Chukwuchekwa, Wolfson Centre
for Magnetics, Institute of Energy, Cardiff School of Engineering, Cardiff
University, CF24 3AA, Cardiff, UK. Tel.: +44 77 69 724237; E-mail:
[email protected]
Abstract: Magnetic Barkhausen Noise (MBN) can be used for non-destructive
evaluation of structural properties of ferromagnetic materials. An EMF due to
Barkhausen noise is induced in a coil near the surface or encircling a
ferromagnetic material which is subjected to an alternating external magnetic
field. MBN measurements were carried out on samples of Non Grain-Oriented (NG0)
steel to determine the variation with thickness and silicon content. The
results show that the rms value of Barkhausen Noise (BN) amplitude increases
with decreasing sample thickness and increasing silicon content. This is
explained in terms of eddy current effects which increase with increasing
sample thickness and reduce with increasing silicon content. Moving domain
walls induce eddy currents in the sample which give rise to effective retarding
pressures on the walls which in turn leads to reduced magnetic Barkhausen noise
amplitude.
Keywords: Magnetic Barkhausen Noise, non-oriented steel, domain walls
