Picotesla Magnetic Sensors for Low-Frequency Applications

Authors

Sy-Hwang Liou, University of Nebraska-LincolnFollow
Xiaolu Yin, University of Nebraska-Lincoln
Stephen Russek, National Institute of Standards and TechnologyFollow
Ranko Heindl, National Institute of Standards and TechnologyFollow
F. C. S. Da Silva, National Institute of Standards and TechnologyFollow
J. Moreland, National Institute of Standards and TechnologyFollow
David P. Pappas, National Institute of Standards and TechnologyFollow
L. Yuan, Western Digital Corporation
J. Shen, Western Digital Corporation

Date of this Version

10-2011

Citation

IEEE TRANSACTIONS ON MAGNETICS, VOL. 47, NO. 10, OCTOBER 2011; Digital Object Identifier 10.1109/TMAG.2011.2157997

Abstract

We demonstrate a simple low-power, magnetic sensor system suitable for high-sensitivity magnetic-field mapping, based on solid-state magnetic tunnel junction devices with minimum detectable fields in a 100 pT range at room temperature. In this paper, we discuss a method that uses multilayer thin films to improve the performance of the soft ferromagnetic layer in magnetoresistive sensor applications, by reducing the coercivity and/or improving the reversibility.We have used it in the design of our new magnetic sensor. This sensor has a sensitivity as high as 750%/mT. The magnetic sensor only dissipates 1 mW of power while operating under an applied voltage of 1 V.