An Extremely Low Equivalent Magnetic Noise Magnetoelectric Sensor

Abstract

Extremely low equivalent magnetic noise in a Metglas/piezofiber magnetoelectric (ME) magetic‐field sensor, realized through a combination of a giant ME effect and a reduction in constituent internal noise sources, is demonstrated. The ME coefficient is 52 V cm−1 Oe−1 at low frequency, the 1 Hz equivalent magnetic noise is 5.1 pT Hz−1/2, and the magnetic field sensitivity is 10 nT.

Thermal stability of magnetoelectric sensors

“…Since the sensitivity of ME composites is mainly limited by the charge noise density (N c ) and the ME charge coefficient, the sensitivity can be estimated as 7,8 FIG. 1.…”

“…3,4 To date, ME laminated composites of magnetostrictive Metglas foils and piezoelectric Pb(Zr,Ti)O 3 or PZT have been widely investigated in various operational modes and optimized for use in magnetic field detection applications. [5][6][7] Highly sensitive, room temperature, passive magnetic field sensors have been developed based on ME laminates. Such magnetic sensors have been shown to have noise floors on the order of pT/HHz for Metglas/PZT foil laminates.…”

Enhanced magnetoelectric effect in self-stressed multi-push-pull mode Metglas/Pb(Zr,Ti)O3/Metglas laminates

“…8 The values of C and tan d were measured using an impedance analyzer (Agilent 4292 A). No obvious changes were found between laminates with or without self-stress at low frequencies.…”

“…Significantly higher values of the ME voltage coefficient (a ME ) have been reported in tri-layer Metglas/piezo-fibers/Metglas structures with a multi-push-pull configuration that is longitudinally and poled longitudinally magnetized (L-L). 8 It is know that application of suitable stress to magnetostrictive materials results in a maximum value of the effective linear piezomagnetic coefficient. 9 Under moderate stress, the piezoelectric coefficient of piezoelectric materials can also be increased.…”

Shear-mode magnetostrictive/piezoelectric composite with an enhanced magnetoelectric coefficient

“…In this case, the ME effect depends on composite microstructure and configuration, coupling interaction across magneto-elasto-electric interfaces, and the individual properties of the composite components. [2][3][4][5][6][7][8][9][10][11][12] To date, laminated composites of magnetostrictive Metglas or Terfenol-D and piezoelectric Pb(Mg 1/3 Nb 2/3 ) O 3 -30PbTiO 3 (PMN-PT) or Pb(Zr,Ti)O 3 (PZT) possess the largest ME effects and highest sensitivity to magnetic field variations. This is due to the constituent phases having the highest individual magnetostrictive and piezoelectric coefficients.…”