Meander thin-film biosensor fabrication to investigate the influence of structural parameters on the magneto-impedance effect

Abkar Sayad, Shah Mukim Uddin, Jianxiong Chan, Efstratios Skafidas, Patrick Kwan

Research output: Contribution to journalArticleResearchpeer-review

2 Citations (Scopus)

Abstract

Thin-film magneto-impedance (MI) biosensors have attracted significant attention due to their high sensitivity and easy miniaturization. However, further improvement is required to detect weak biomagnetic signals. Here, we report a meander thin-film biosensor preparation to investigate the fabrication parameters influencing the MI effect. Specifically, we hypothesized that an optimal film thickness and sensing area size ratio could be achieved to obtain a maximum MI ratio. A meander multilayer MI biosensor based on a NiFe/Cu/NiFe thin-film was designed and fabricated into 3-, 6-, and 9-turn models with film thicknesses of 3 μm and 6 μm. The 9-turn biosensor resembled the largest sensing area, while the 3- and 6-turn biosensors were designed with identical sensing areas. The results indicated that the NiFe film thickness of 6 μm with a sensing area size of 14.4 mm2 resembling a 9-turn MI biosensor is the optimal ratio yielding the maximum MI ratio of 238%, which is 70% larger than the 3- and 6-turn structures. The 3- and 6-turn MI biosensors exhibited similar characteristics where the MI ratio peaked at a similar value. Our results suggest that the MI ratio can be increased by increasing the sensing area size and film thickness rather than the number of turns. We showed that an optimal film thickness to sensing area size ratio is required to obtain a high MI ratio. Our findings will be useful for designing highly sensitive MI biosensors capable of detecting low biomagnetic signals.

Original languageEnglish
Article number6514
Number of pages17
JournalSensors
Volume21
Issue number19
DOIs
Publication statusPublished - 1 Oct 2021

Keywords

  • Magnetic materials
  • Magneto-impedance
  • Meander
  • Sensing area
  • Thickness
  • Turns

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