SQUIDs demonstrate record sensitivities to small magnetic moments but are typically sensitive only to the field component that is normal to the plane of the ring and out-of-plane with respect to the scanned surface. We have developed a novel nanoscale three-junction SQUID, which is fabricated on the apex of a trimmed sharp tip. Thanks to the device's unique three-dimensional structure, it exhibits a tunable sensitivity to both inplane and out-of-plane fields.
This device, integrated into our scanning microscope, offers an unprecedented ability to localy probe magnetic structures and independently measure the different components of the magnetic field with outstanding spin sensitivity. This opens the door to several applications such as the study of local transport currents distribution in complex samples, current-carrying edge states, transport in surface states, spin polarized currents, imaging of spin accumulation in spintronics devices, and detection of single spins with in-plane polarization, where the in-plane component of the magnetic field provides the more local and essential information.
- Left: SEM image of the device.
- Center: Measurement of the in-plane magnetic field component, capturing the local nature of the current.
- Right: Measurement of the out-of-plane magnetic field component.