Nanowire GMR Thin Films for Magnetic Sensors

B. Cox, N. Crews
Louisiana Tech University, US

Keywords: giant magnetoresistance, GMR, magnetic sensors, magnetic nanowires, nanowire thin film, oxidation removal


The discovery of Giant magnetoresistance (GMR) in 1988 by Albert Fert and Peter Grünberg started a concentrated effort by researchers to comprehend the phenomenon and find suitable applications [1]. We present an elegant technique for the fabrication of CoNiFeCu/Cu multilayer GMR nanowire thin films for magnetic sensing applications. Using an electrodeposition technique, current perpendicular to the plane (CPP) multilayer GMR nanowires are fabricated inside of aluminum oxide (AAO) templates. After GMR nanowires are fabricated, they are transferred to receiving substrates, such as PET plastic, using a vacuum filtration technique and a PDMS stamp. Using this technique, each AAO template of 3.4 cm2 yields nanowires sufficient for a GMR sensor coverage of approximately 300 cm2 and the magnetic sensors are transparent, flexible, and scalable. The electrical sheet resistance of these sensors is approximately 100-10k Ω/, with a %GMR on the order of 10% at room temperature. The advantages of magnetic sensors created with nanowire-GMR thin films versus traditional commercially available magnetic sensors are that these thin film sensors can be patterned on transparent and flexible substrates, are less expensive to fabricate, use less power, and have potentially higher signal to noise ratios.