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Sensitive magnetometry has been established as a powerful technique for the characterization and testing of materials, with the most demanding applications relying on SQUID magnetometers operating at cryogenic temperatures. The recent development of compact, non-cryogenic atomic magnetometers with sub-femtotesla sensitivity and easy sample access has opened up a number of new possibilities. We give examples of sample thermal demagnetization measurements with sensitivity better than 10−9 emu/Hz½ up to 420 °C and of magnetic detection of water droplets on an aluminum surface. Recent research on magnetometry with laser-cooled atoms and color centers in diamond promises to extend the reach of atomic magnetic sensors to the micro- and nanoscale. [Copyright &y& Elsevier]

Some of the most sensitive methods of measuring magnetic fields use interactions of resonant light with atomic vapour. Recent developments in this vibrant field have led to improvements in sensitivity and other characteristics of atomic magnetometers, benefiting their traditional applications for measurements of geomagnetic anomalies and magnetic fields in space, and opening many new areas previously accessible only to magnetometers based on superconducting quantum interference devices. We review basic principles of modern optical magnetometers, discuss fundamental limitations on their performance, and describe recently explored applications for dynamical measurements of biomagnetic fields, detecting signals in NMR and MRI, inertial rotation sensing, magnetic microscopy with cold atoms, and tests of fundamental symmetries of nature. [ABSTRACT FROM AUTHOR]

The article discusses the potential use of diamond magnetometers in single-spin nuclear magnetic resonance (NMR) detection. The atomic spin in a crystal defect in diamond nanoparticle can be manipulated with light, responding to the magnetic field generated by the spins in a sample. Also discussed are the properties of nitrogen-vacancy centers in diamond, the association of the finite magnetic moments of electrons and nuclei to their spins, magnetometry techniques and the detection of magnetic fields from single spins.

Abstract: Atomic magnetometers are emerging as an alternative to SQUID magnetometers for detection of biological magnetic fields. They have been used to measure both the magnetocardiography (MCG) and magnetoencephalography (MEG) signals. One of the virtues of the atomic magnetometers is their ability to operate as a multi-channel detector while using many common elements. Here we study two configurations of such a multi-channel atomic magnetometer optimized for MEG detection. We describe measurements of auditory evoked fields (AEF) from a human brain as well as localization of dipolar phantoms and auditory evoked fields. A clear N100m peak in AEF was observed with a signal-to-noise ratio of higher than 10 after averaging of 250 stimuli. Currently the intrinsic magnetic noise level is 4fTHz−1/2 at 10Hz. We compare the performance of the two systems in regards to current source localization and discuss future development of atomic MEG systems. [Copyright &y& Elsevier]