Characteristics of a parametric magnetostrictive oscillator

Parametric properties of a magnetostrictive oscillator are characterized by observing the strain dynamics of a magnetically excited metallic glass ribbon. A magnetostrictive ribbon excited by a total magnetic field H=H_dc+h_p cos(ωt)+h_Ω cos(Ωt) generates strain responses at frequencies ω, Ω, ω±Ω, thereby making the device resemble a parametric oscillator operating in the three-photon mode. Close to an instability in the nonlinear strain dynamics of such materials, the authors observed dependence of the gain of the strain e_Ω on pump amplitude h_p and detuning frequency, while DC field dependent gain was observed in the strain e_ω±Ω. This behavior is generic to parametric devices and is not predicted by the quadratic coherent rotation model of magnetostriction. Experimental verification of greater than 35-dB small signal gain in a fiber-optic AC magnetometer is demonstrated