Giant magnetoimpedance intrinsic impedance and voltage sensitivity of rapidly solidified Co sub(66)Fe sub(2)Cr sub(4)Si sub(13)B sub(15) amorphous wire for highly sensitive sensors applications

• Published in: Applied physics. A, Materials science & processing Vol. 122; no. 11; pp. 1 - 8
• Main Authors: Das, Tarun K, Banerji, Pallab, Mandal, Sushil K
• Format: Journal Article
• Language: English
• Published: 01-11-2016
• Subjects: Behavior; Electric potential; Giant magnetoimpedance; Impedance; Sensitivity; Sensitivity analysis; Voltage; Wire
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-016-0478-9

We report a systematic study of the influence of wire length, L, dependence of giant magneto-impedance (GMI) sensitivity of Co sub(66)Fe sub(2)Cr sub(4)Si sub(13)B sub(15) soft magnetic amorphous wire of diameter ~100 mu m developed by in-water quenching technique. The magnetization behaviour (hysteresis loops) of the wire with different length (L = 1, 2, 3, 5, 8 and 10 cm) has been evaluated by fuxmetric induction method. It was observed that the behaviour of the hysteresis loops change drastically with the wire length, being attributed to the existence of a critical length, L sub(C), found to be around 3 cm. GMI measurements have been taken using automated GMI measurement system and the GMI sensitivities in terms of intrinsic impedance sensitivity (S sub( Omega /Am) super(-1)) and voltage sensitivity (S sub(V/Am) super(-1)) of the wire have been evaluated under optimal bias field and excitation current. It was found that the maximum (S sub( Omega /Am) super(-1)) sub(max) approximately 0.63 Omega /kAm super(-1)/cm and (S sub(V/Am) super(-1)) sub(max) approximately 3.10 V/kAm super(-1)/cm were achieved at a critical length L sub(C) ~ 3 cm of the wire for an AC current of 5 mA and a frequency of 5 MHz. These findings provide crucial insights for optimization of the geometrical dimensions of magnetic sensing elements and important practical guidance for designing high sensitive GMI sensors. The relevant combinations of magnetic material parameters and operating conditions that optimize the sensitivity are highlighted.