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We report on the resonant excitation of spin waves in micro-structured magnetic thin films by short-wavelength surface acoustic waves (SAWs). The spin waves as well as the acoustic waves are studied by micro-focused Brillouin light scattering spectroscopy. At low magnetic bias fields, a resonant phonon–magnon conversion is possible, which results in the excitation of short-wavelength spin waves. Using micromagnetic simulations, we verify that during this excitation both energy and linear momentum are conserved and fully transferred from the SAW to the spin wave. This conversion can already be detected after an interaction length of a few micrometers. Thus, our findings pave the way for miniaturized magneto-elastic spin-wave emitters for magnon computing.

A compact analytical model is proposed along with a parameter extraction methodology to accurately capture the steady-state (DC) sequential tunnelling current observed in the subthreshold region of the transfer IDS − VGS characteristics of MOSFETs at cryogenic temperatures. The model is shown to match measurements of p-MOSFETs and n-MOSFETs manufactured in a commercial 22nm FDSOI foundry technology, with reasonable accuracy across bias conditions and temperature (2 K -50 K). Furthermore, the extracted model parameters are used to analyze the impact of the gate and drain voltages and of layout geometry on the device characteristics.

This paper proposes high sensitivity temperature sensors based on single port surface acoustic wave (SAW) devices with GHz resonance frequencies, developed on GaN/SiC and GaN/Sapphire, which permit wide range, accurate temperature determinations. In contrast with GaN/Si SAW based temperature sensors, SiC and Sapphire substrates enable the proper functionality of these devices up to 500 • C (773 K), as the high resistivity Si substrate becomes conductive at temperatures exceeding 250 • C (523 K) due to the relative low bandgap (and high intrinsic carrier concentrations). Low temperature measurements were carried out using a cryostat between -266 • C (7 K) and room temperature (RT) while the high temperature measurements are made on a modified RF probe station. A polynomial fit was used below RT and a linear approximation was evidenced between RT and 500 • C (773 K). The structures were simulated at different selected temperatures based on a method that couples Finite Element Method (FEM) and Coupling of Modes (COM). The measured temperature coefficient of frequency (TCF) is about 46 ppm/ • C for GaN/SiC SAWs and reaches values of 96 ppm/ • C for GaN/Sapphire SAW in the temperature range 25 -500 • C (298 K -773 K).INDEX TERMS Surface acoustic wave, temperature sensor, GaN, SiC, sapphire, high temperature measurements, low temperature measurements.

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