Detection of Magnetically Labeled Cells Using Wavelike Permalloy Nanowires

Permalloy nanowires of 150, 300, 500, and 800 nm widths deposited onto wavelike silicon trenches were designed as single-cell sensing devices. Magnetoresistance curves before and after attaching a single magnetic cell on the nanowires were measured when magnetic fields were applied in various directions. It was observed that the highest sensitivity (27%) in switching field variation after a cell was attached can be obtained when the field was applied perpendicular to the plane of the 150-nm-wide nanowire. The highest sensitivity (25.5%) in magnetoresistance ratio variation occurred in the 800-nm-wide nanowire in the same field direction.