Spatial Microwave Magnetic Field Distribution Mapped by the Permalloy/Ta Bilayer Sensor

In this work, a microwave (MW) magnetic field sensor based on a Permalloy (Py)/ Tantalum (Ta) bilayer thin film is developed. By determining the Lorentzian components of the inverse spin Hall and spin rectification voltage of the bilayer film, the MW magnetic field aptitude distributions in the three-dimensional space near a shorted MW probe were obtained. The detection limit and sensitivity of the system are obtained to be <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2.1 \times 10^{-4} \text{Oe}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$7.7 \mu \mathrm{V} / \text{Oe}^{2}$</tex>, respectively. The method provides a convenient way for characterizing the MW magnetic field in small devices and complex structures, which can be used to improve the performances of microwave integrated circuit.