Title :
Single paramagnetic bead detection and direct measurement of the spatial magnetic resolution using novel nanocomposite Hall sensors
Author :
Gabureac, Mihai S. ; Bernau, Laurent ; Boero, Giovanni ; Utke, Ivo
Author_Institution :
EMPA, The Swiss Fed. Labs. for Mater. Sci. & Technol., Thun, Switzerland
Abstract :
We show that nanocomposite materials formed by superparamagnetic nanoparticles embedded in a matrix are very good candidates for a novel generation of Hall nano-sensors with high spatial magnetic resolution, capable of detection superparamagnetic beads suspended at different heights on top of the sensor. Two detection schemes were used: the one ex situ, using a combination of AC and DC orthogonal fields, with the bead placed on top of the sensor and the other one in situ, using nanomanipulation. The z spatial resolution can be determined directly from the in situ detection, by suspending the bead at different heights above the sensor, using only one magnetic field (AC) and nanomanipulation. The position of the bead is confirmed by direct electron microscope imaging. The Hall sensors were directly written by an electron beam and the active area was refined by focused ion beam milling below 200 nm, that allowed increasing the spatial magnetic resolution.
Keywords :
Hall effect devices; electron beams; electron microscopes; focused ion beam technology; magnetic fields; milling; nanocomposites; nanoparticles; nanosensors; paramagnetic materials; superparamagnetism; electron beam; electron microscope imaging; ex situ detection scheme; focused ion beam milling; in situ detection scheme; magnetic field; nanocomposite Hall nanosensor; nanocomposite material; nanomanipulation; spatial magnetic resolution; spatial magnetic resolution measurement; superparamagnetic bead detection; superparamagnetic nanoparticle; Magnetic films; Magnetic resonance imaging; Saturation magnetization; Substrates;
Conference_Titel :
Nanotechnology (IEEE-NANO), 2012 12th IEEE Conference on
Conference_Location :
Birmingham
Print_ISBN :
978-1-4673-2198-3
DOI :
10.1109/NANO.2012.6322104