# Tunnel Magnetoresistance Sensors with Magnetostrictive Electrodes: Strain Sensors

Tavassolizadeh, Ali; Rott, Karsten; Meier, Tobias; Quandt, Eckhard; Hölscher, Hendrik; Reiss, Günter; Meyners, Dirk

Abstract:
Magnetostrictive tunnel magnetoresistance (TMR) sensors pose a bright perspective in micro- and nano-scale strain sensing technology. The behavior of TMR sensors under mechanical stress as well as their sensitivity to the applied stress depends on the magnetization configuration of magnetic tunnel junctions (MTJ)s with respect to the stress axis. Here, we propose a configuration resulting in an inverse effect on the tunnel resistance by tensile and compressive stresses. Numerical simulations, based on a modified Stoner–Wohlfarth (SW) model, are performed in order to understand the magnetization reversal of the sense layer and to find out the optimum bias magnetic field required for high strain sensitivity. At a bias field of -3.2 kA/m under a 0.2 × 10$^{-3}$ strain, gauge factors of 2294 and -311 are calculated under tensile and compressive stresses, respectively. Modeling results are investigated experimentally on a round junction with a diameter of 30 ± 0.2 μm using a four-point bending apparatus. The measured field and strain loops exhibit nearly the same trends as the calculated ones. Also, the gauge factors are in the same rang ... mehr

 Zugehörige Institution(en) am KIT Institut für Mikrostrukturtechnik (IMT) Publikationstyp Zeitschriftenaufsatz Jahr 2016 Sprache Englisch Identifikator ISSN: 1424-8220KITopen-ID: 1000062638 HGF-Programm 43.22.01 (POF III, LK 01) Erschienen in Sensors Band 16 Heft 11 Seiten 1902 Bemerkung zur Veröffentlichung http://www.mdpi.com/1424-8220/16/11/1902/htm Schlagworte tunnel magnetoresistance, inverse magnetostriction, strain sensors Nachgewiesen in Web of ScienceScopus
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