A micro-fluxgate sensor based on the Matteucci effect of amorphous magnetic fibers

Citation
Pd. Dimitropoulos et Jn. Avaritsiotis, A micro-fluxgate sensor based on the Matteucci effect of amorphous magnetic fibers, SENS ACTU-A, 94(3), 2001, pp. 165-176
Citations number
37
Categorie Soggetti
Instrumentation & Measurement
Journal title
SENSORS AND ACTUATORS A-PHYSICAL
ISSN journal
09244247 → ACNP
Volume
94
Issue
3
Year of publication
2001
Pages
165 - 176
Database
ISI
SICI code
0924-4247(20011120)94:3<165:AMSBOT>2.0.ZU;2-7
Abstract
The design, construction and performance of a novel micro-fluxgate sensor i s presented in this work. The sensor is based on the large Matteucci effect that is observed in amorphous fibers of typical stoicheiometry Fe77.5Si7.5 B15 after proper annealing. The sensor requires a single planar coil to fun ction, which was constructed with conventional printed-circuit techniques a long with the sensor signal conditioning circuitry. A new signal extraction technique was applied that is superior to the conventional second-order-ha rmonic concept, as far as sensitivity and signal-to-noise ratio are concern ed. A conventional fiber, with diameter 125 mum, and a glass-covered fiber, with core diameter 20 mum and glass-cover thickness 20 mum, were used as m agnetic cores in the fluxgate sensor. The amorphous fibers were mounted, su bsequently, above a planar coil by soldering each two ends without any furt her mechanical treatment, like bending or twisting. Current annealing was p erformed before mounting, for both magnetic core types in order to optimize the inductive response of the fibers. The sensor sensitivity, before ampli fication, was measured to be 74000 V/T. The low magnetic noise observed all ows for a relatively high overall precision, which in the case of glass-cov ered fiber has been verified to be 60 nT; this figure may easily improve by known signal conditioning techniques. The overall sensor head dimensions a re 60 mm x 30 mm. Further scaling down may be achieved by means of advanced lithographic techniques in the case of glass-covered amorphous fibers only , which exhibit significant Matteucci effect in lengths down to 5 nim. (C) 2001 Elsevier Science B.V. All rights reserved.