Compact room-temperature induction magnetometer with superconducting quantum interference device level field sensitivity

In this article, we describe significant developments in the design and construction of robust and compact room-temperature induction magnetometers with magnetic field sensitivities comparable to those usually associated only with superconducting quantum interference device (SQUID) magnetometers operating at cryogenic temperatures. In this system, we make use of both temperature independent amorphous magnetic core materials and ultralow noise signal processing electronics to achieve a spot noise figure of 14¿fT/ at 300 Hz measured in a specially constructed, very low field environment. We present results over an operating bandwidth of 30 mHz to 3 kHz and show that linearity is preserved over almost six decades in an applied magnetic field amplitude. We compare the spectral noise of our systems with recently published data on SQUID magnetometers. © 2003 American Institute of Physics