Fabrication of micro-sensors integrated with single nanometer magnetic particles: Detection of the reversal of the magnetization.

Nanometer magnetic particles in intimate coupling with micro-sensors have been fabricated by a novel process in order to detect the reversal of the magnetization by magnetoresistance measurements. The tailoring of the single particles on the top of the sensors needs the in-situ control of the etch layer sequence during the ion beam etching: we are able to end the etching in layers as thin as 4nm with a precision better than 1nm. Thanks to the good sensitivity of our fabricated set-up, we show the first study of the reversal of the magnetization in nanometer size samples by magnetoresistance measurements.