Analysis and simulation of natural frequency for the MSAW-oriented RGMFS samples

The magnetic surface acoustic wave (MSAW) devices developed in recent years are a class of tunable surface acoustic wave devices (such as filters, tuners, oscillators, etc.) which are important parts of radar, sonar, TV, computers and other modern communication systems. Giant magnetostrictive thin films (RGMFs) have high energy, large magnetic response, and high elastic modulus as well as the function that sound speed can alter by changing the magnetic field. Thus, RGMFs can be used to make tunable MSAW devices. The vibration characteristics of the device components are directly related to the service status and the life of devices. In order to optimize and design RGMFs materials, in this paper, SmFe₂ samples with polyimide (PI) and the glass as substrates are studied, and the natural frequencies of SmFe₂ monolayer samples, with different deposition thickness, are derived and simulated by the method of equivalent-section. Furthermore, vibration data (including natural frequencies and resonant amplitudes) of the SmFe₂ samples are measured by the Helmholtz resonance system. The results show that the differences between the theoretical predictions and the experimental results are within 8%. Therefore, the equivalent-section method is feasible to predict the natural frequency of RGMFs samples. The work establishes a basis for the development of MSAW devices using RGMFs materials.