title: Superconducting quantum interference device microsusceptometer balanced over a wide bandwidth for nuclear magnetic resonance applications.
abstract: Superconducting Quantum Interference Device (SQUID) microsusceptometers have been widely used to study magnetic properties of materials at microscale. As intrinsically balanced devices, they could also be exploited for direct SQUID-detection of nuclear magnetic resonance (NMR) from micron sized samples, or for SQUID readout of mechanically detected NMR from submicron sized samples. Here, we demonstrate a double balancing technique that enables achievement of very low residual imbalance of a SQUID microsusceptometer over a wide bandwidth. In particular, we can generate ac magnetic fields within the SQUID loop as large as 1 mT, for frequencies ranging from dc up to a few MHz. As an application, we demonstrate direct detection of NMR from (1)H spins in a glycerol droplet placed directly on top of the 20 μm SQUID loops.
authors.affiliation: Istituto di Fotonica e Nanotecnologie, CNR - Fondazione Bruno Kessler, I-38123 Povo, Trento, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Vinante
authors.affiliation: Dipartimento di Fisica, Università di Trento, I-38123 Povo, Trento, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Mezzena
authors.affiliation: Istituto di Fotonica e Nanotecnologie, CNR - Fondazione Bruno Kessler, I-38123 Povo, Trento, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Falferi