SQUID-on-tip with single-electron spin sensitivity for high-field and ultra-low temperature nanomagnetic imaging.
Nanoscale
; 12(5): 3174-3182, 2020 Feb 07.
Article
em En
| MEDLINE
| ID: mdl-31967152
ABSTRACT
Scanning nanoscale superconducting quantum interference devices (nanoSQUIDs) are of growing interest for highly sensitive quantitative imaging of magnetic, spintronic, and transport properties of low-dimensional systems. Utilizing specifically designed grooved quartz capillaries pulled into a sharp pipette, we have fabricated the smallest SQUID-on-tip (SOT) devices with effective diameters down to 39 nm. Integration of a resistive shunt in close proximity to the pipette apex combined with self-aligned deposition of In and Sn, has resulted in SOTs with a flux noise of 42 nΦ0 Hz-1/2, yielding a record low spin noise of 0.29 µB Hz-1/2. In addition, the new SOTs function at sub-Kelvin temperatures and in high magnetic fields of over 2.5 T. Integrating the SOTs into a scanning probe microscope allowed us to image the stray field of a single Fe3O4 nanocube at 300 mK. Our results show that the easy magnetization axis direction undergoes a transition from the ã111ã direction at room temperature to an in-plane orientation, which could be attributed to the Verwey phase transition in Fe3O4.
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1
Coleções:
01-internacional
Base de dados:
MEDLINE
Tipo de estudo:
Diagnostic_studies
Idioma:
En
Revista:
Nanoscale
Ano de publicação:
2020
Tipo de documento:
Article