Three-Axis Vector Nano Superconducting Quantum Interference Device

We present the design, realization, and performance of a three-axis vector nano superconducting quantum interference device (nanoSQUID). It consists of three mutually orthogonal SQUID nanoloops that allow distinguishing the three components of the vector magnetic moment of individual nanoparticles placed at a specific position. The device is based on Nb/HfTi/Nb Josephson junctions and exhibits line widths of ∼250 nm and inner loop areas of 600 × 90 and 500 × 500 nm2. Operation at temperature T = 4.2 K under external magnetic fields perpendicular to the substrate plane up to ∼50 mT is demonstrated. The experimental flux noise below ∼250 n Φ 0 / Hz in the white noise limit and the reduced dimensions lead to a total calculated spin sensitivity of ∼630 μ B / Hz and ∼70 μ B / Hz for the in-plane and out-of-plane components of the vector magnetic moment, respectively. The potential of the device for studying three-dimensional properties of individual nanomagnets is discussed.