Over the last decades, the use of Surface Acoustic Waves (SAW) has emerged as a promising technology in many applications such as filters, signal processing but also sensors. We report the fabrication and the characterization of a SAW delay line magnetic field sensor using uniaxial multi-layered 14×[TbCo2(3.7nm)/FeCo(4nm)] nanostructured thin film deposited on Y36° Lithium Niobate (Figure 1a). The sensor shows an interesting dependency to a tunable bias magnetic field with different orientations relative to the easy axis. The obtained results are well explained using an equivalent piezo-magnetic model described in a previous work.
The magnetic field hz of a moving Pearl vortex in a superconducting thin-film in (x,y) plane is studied with the help of the time-dependent London equation. It is found that for a vortex at the origin moving in +x direction, hz(x,y) is suppressed in front of the vortex, x>0, and enhanced behind (x<0). The distribution asymmetry is proportional to the velocity and to the conductivity of normal quasiparticles. The vortex self-energy and the interaction of two moving vortices are evaluated.
Originally, sensors based on surface acoustic waves are fabricated using photolithography, which becomes extremely expensive when a small series or even single elements are needed for the research. A laser thin film local evaporation technique is proposed to substitute the photolithography process in the production of surface acoustic wave based inertial sensors prototypes. To estimate its potential a prototype of a surface acoustic wave gyroscope sensing element was fabricated and tested. Its was shown that the frequency mismatch is no more than 1%, but dispersion of the wave on small inertial masses leads to a spurious parasitic signal on receiving electrodes. Possible ways of its neglecting is discussed.
Highly Sensitive Surface Acoustic Wave Magnetic Field Sensor Using Multilayered TbCo2/FeCo Thin Film
