Magnetic sensing via ultrasonic excitation.

Author: Yamada H, Takashima K, Ikushima K, Toida H, Sato M, Ishizawa Y.
Affiliation: Department of Applied Physics, Tokyo University of Agriculture and Technology, Nakacho, Koganei, Tokyo 184-8588, Japan.
Conference/Journal: Rev Sci Instrum.
Date published: 2013 Apr
Other: Volume ID: 84 , Issue ID: 4 , Pages: 044903 , Special Notes: doi: 10.1063/1.4803188 , Word Count: 103

We present ultrasonic techniques for magnetic measurements. Acoustically modulated magnetization is investigated with sensitive rf detection by narrowband loop antennas. Magnetization on the surface of ferromagnetic metals is temporally modulated with the rf frequency of the irradiated ultrasonic waves, and the near-field components emitted from the focal point of the ultrasonic beam are detected. Based on the principle of the acoustically stimulated electromagnetic (ASEM) response, magnetic sensing and tomography are demonstrated by ultrasonic scanning. We show that ASEM imaging combines good acoustic resolution with magnetic contrast. The sensitivity of this method is estimated to be about 6 G/Hz(1∕2) in our current setup.
PMID: 23635223