Resonance modes of freestanding magnetoelastic resonator and the application in viscosity measurement

The magnetoelastic material possesses several resonance modes, but the magnetoelastic sensors operate in basically the fundamental resonant frequency. This paper investigates the resonance modes of a freestanding ME resonator, tests these modes in liquids with different viscosity and measures the viscosity of human blood. Five resonance modes with different amplitudes appear in the frequency range of 30-280 kHz. The resonance modes are affected by the direction and strength of the DC bias magnetic field. Compared with the width of the resonance peak, the quality factor cannot correctly reflect the sharpness of the resonance peak of different resonance modes. The five modes are affected by liquid. The first mode has better resolution in determining the resonant frequency, but the higher mode is more sensitive to viscosity. The ME resonator can be used to quickly distinguish the viscosity of blood.