Proposed magnetometer design could measure atomic-scale properties
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temperature. Its magnetic field may be altered through Proposed magnetometer design a dipolar interaction near the “nonmagcould measure atomic-scale properties netic” material, leading to anisotropy in its electronic structure. n medical magnetic resonance imagTheoreticians have calculated how ing (MRI), radio waves induce magthe NV center electronic structure changnetic changes in tissues, which doces when subjected to a magnetic field tors can detect with a sensitive probe. induced by the sample. They found that Similarly, scanning probe techniques the magnetic response signature has the detect changes in single electron spins same symmetry as the changes in electo map fine-scale magnetic fields ustronic states that result from a temperaing a magnetically sensitive probe. But ture change, a well-studied phenomenon. materials such as superconductors and As an example, they located the indiamagnets, whose magnetic properterface between a ferromagnetic and ties only occur internally at the atomic magnetically dead material in a magscale, do not emanate a magnetic field netic tunnel junction—a layered system in isolation, and thus cannot be probed of commercial interest for its use in thinfilm technology. “With our technique, you should be able to identify that interface even though it’s buried,” Flatté a Current density says. He believes it possible to measure -jmax 0 jmax the thickness of magnetic insulators with better than 0.1 Å accuracy. “An attractive aspect of this particular proposal is the potential expansion of the range of materials that can be sensed, and is yet another example of how quantum engineering can be used to improve sensing to impact the materials and physics communities,” says David Awschalom, professor of spintronics and quantum information at The University of Chicago’s Institute for Molecular Engineering, who was not involved in the publication. While Flatté continues theoretical work toward implementing different probes and improvb Magnetic induction ing predicted senIncreasing relative magnetic permeability Bmin Bmax sitivity, van Bree is now seeking to realize the atomicscale magnetometer experimentally in collaboration with Awschalom’s laboratory. They look forward to new abilities for sensing a wide range of materials that have no natural external magnetic field. A spin (probe) placed in Region I, adjacent to Region II with different magnetic permeability (a), leads to a detectable Rachel Berkowitz (b) magnetic induction (magnitude indicated by color). Credit: Michael Flatté.
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• VOLUME 42 • JUNE 2017Kainan • www.mrs.org/bulletin Downloaded MRS fromBULLETIN https://www.cambridge.org/core. University, on 03 Sep 2017 at 10:45:24, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1557/mrs.2017.124
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