Coupling-Induced Cooperative behaviour in Dynamic Ferromagnetic Cores in the Presence of a Noise Floor

Recently, we have shown the emergence of oscillations in overdamped undriven nonlinear dynamic systems subject to carefully crafted coupling schemes and operating conditions. Here, we summarize experimental results obtained on a system of N = 3 coupled ferromagnetic cores, the underpinning of a "coupled-core fluxgate magnetometer" (CCFM); the oscillatory behaviour is triggered when the coupling constant exceeds a threshold value (bifurcation point), and the oscillation frequency exhibits a characteristic scaling behaviour with the "separation" of the coupling constant from its threshold value, as well as with an external target DC magnetic flux signal. The oscillations, which can be induced at frequencies ranging from a few Hz to high-kHz, afford a new detection scheme for weak target magnetic signals. We also present the first (numerical) results on the effects of a (Gaussian, exponentially correlated) noise floor on the spectral properties of the system response. (c) 2005 Elsevier B.V. All rights reserved.