Modelling and design of planar Hall effect bridge sensors for low-frequency applications
2013 (English)In: Sensors and Actuators A-Physical, ISSN 0924-4247, Vol. 189, 459-465 p.Article in journal (Refereed) Published
The applicability of miniaturized magnetic ﬁeld sensors is being explored in several areas of magneticﬁeld detection due to their integratability, low mass, and potentially low cost. In this respect, differentthin-ﬁlm technologies, especially those employing magnetoresistance, show great potential, being compatible with batch micro- and nanofabrication techniques. For low-frequency magnetic ﬁeld detection,sensors based on the planar Hall effect, especially planar Hall effect bridge (PHEB) sensors, show promising performance given their inherent low-ﬁeld linearity, limited hysteresis and moderate noise ﬁgure. Inthis work, the applicability of such PHEB sensors to different areas is investigated. An analytical modelis constructed to estimate the performance of an arbitrary PHEB sensor geometry in terms of, e.g., sensitivity and detectivity. The model is valid for an ideal case, e.g., disregarding shape anisotropy effects, andalso incorporates some approximations. To validate the results, modelled data was compared to measurements on actual PHEBs and was found to predict the measured values within 13% for the investigatedgeometries. Subsequently, the model was used to establish a design process for optimizing a PHEB to aparticular set of requirements on the bandwidth, detectivity, compliance voltage and ampliﬁed signalto-noise ratio. By applying this design process, the size, sensitivity, resistance, bias current and powerconsumption of the PHEB can be estimated. The model indicates that PHEBs can be applicable to severaldifferent areas within science including satellite attitude determination and magnetic bead detection inlab-on-a-chip applications, where detectivities down towards 1 nT Hz−0.5at 1 Hz are required, andmaybeeven magnetic ﬁeld measurements in scientiﬁc space missions and archaeological surveying, where thedetectivity has to be less than 100 pT Hz−0.5at 1 Hz.
Place, publisher, year, edition, pages
2013. Vol. 189, 459-465 p.
Magnetoresistance Planar Hall effect Low-frequency noise Detectivity
Other Engineering and Technologies not elsewhere specified
Research subject Engineering Science with specialization in Solid State Physics; Engineering Science with specialization in Materials Science; Engineering Science with specialization in Microsystems Technology
IdentifiersURN: urn:nbn:se:uu:diva-188200DOI: 10.1016/j.sna.2012.10.037ISI: 000314622600055OAI: oai:DiVA.org:uu-188200DiVA: diva2:576768