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Lookup NU author(s): Dr Meghanshu Vashista, Dr Moorthy Vaidhianathasamy
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).
The influence of applied magnetic field strength and frequency response of the pick-up coil on the shape of Magnetic Barkhausen Noise (MBN) profile have been studied. The low frequency MBN measurements have been carried out using 5 different MBN pick-up coils at two different ranges of applied magnetic field strengths on quenched and tempered (QT) and case-carburised and tempered (CT) 18CrNiMo7 steel bar samples. The MBN pick-up coils have been designed to obtain different frequency response such that the peak frequency response varies from similar to 4 kHz to similar to 32 kHz and the amplitude of low frequency signals decreases gradually. At lower applied magnetic field strength of +/- 14,000 A/m, all the pick-up coils produced a single peak MBN profile for both QT and CT sample. However, at higher applied magnetic field strength of +/- 22,000 A/m, the MBN profile showed two peaks for both QT and CT samples for pick-up coils with peak frequency response up to similar to 17 kHz. Also, there is systematic reduction in peak 2 for QT sample and asymmetric reduction in the heights of peak 1 and peak 2 for CT sample with increase in peak frequency response of the pick-up coils. The decreasing sensitivity of pick-up coils with increasing peak frequency response to MBN signal generation is indicated by the gradual reduction in width of MBN profile and height of peak 2 in the QT sample. The drastic reduction in peak 1 as compared to peak 2 in the CT sample shows the effect of decreasing low frequency response of the pick-up coils on lowering skin-depth of MBN signal detection. This study clearly suggests that it is essential to optimise both maximum applied magnetic field strength and frequency response of the MBN pick-up coil for maximising the shape of the MBN profile for appropriate correlation with the magnetisation process and hence the material properties.
Author(s): Moorthy V; Vashista M
Publication type: Article
Publication status: Published
Journal: Journal of Magnetism and Magnetic Materials
Year: 2013
Volume: 345
Pages: 208-214
Print publication date: 01/11/2013
Online publication date: 28/06/2013
Acceptance date: 04/06/2013
Date deposited: 19/11/2015
ISSN (print): 0304-8853
ISSN (electronic): 1873-4766
Publisher: Elsevier BV
URL: http://dx.doi.org/10.1016/j.jmmm.2013.06.038
DOI: 10.1016/j.jmmm.2013.06.038
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