Flipping field and stability in anisotropic magnetoresistive sensors

New opportunities offered by Cubesats for space research in Latin America: The SUCHAI project case

“…Although several kinds of this particular magnetometer exist (such as: AMR, GMR, MTJ, SDT, EMR, BMR, etc), the most relevant to Cubesat missions are the Giant Magneto Resistance (GMR) and the Anisotropic Magneto-Resistance (AMR). This magnetometer is usually a permalloy of Ni-Fe over a Si wafer, being composed of four of this permalloys arranged in a Wheatstone bridge (Hauser et al, 2003;Honeywell, 2008). The response of this device is non-linear, but a particular technique is used for the linearization: barber poles, designed as conductive shunts formed by Au stripes.…”

Low-frequency noise characterization of a magnetic field monitoring system using an anisotropic magnetoresistance

“…They have a sensitive axis to the magnetic field, the hard axis, and another axis aligned with the sensor magnetization called the easy axis. Taking advantage of these properties, the flipping technique entails the periodic flip of the internal magnetization of the sensor strips by applying switching field pulses (set/reset pulses) generated by a thin film conductor, which is wound around the active area of the sensor [21]. The change of the magnetization direction induces the reversion of the output characteristic; as a result, the sensor output signal is modulated at the frequency of the switched pulses.…”

AMR gradiometer for mine detection

“…3), therefore the signal processing is shifted to a less noisy frequency band of the amplifiers. High flipping pulses (1.5 A peak) are used in order to lower the sensor noise [4] while keeping the maximum power dissipation by a low duty-cycle.…”