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

Document Type

Article

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.