| Abstrak/Abstract |
The Wheatstone bridge-giant magnetoresistance (GMR) sensor with single and double
spin valve thin film was successfully developed for potential biomolecular detection. The GMR
sensor with spin valves structure of [Ta (2nm)/IrMn (10nm)/CoFe (3nm)/Cu (2,2nm)/CoFeB
(10nm)/Ta (5nm)] was fabricated using DC Magnetic Sputtering method. The Fe3O4 magnetic
nanoparticles were synthesized by the co-precipitation method as a magnetic label. The magnetic
properties of the Fe3O4 nanoparticles measured are the saturation magnetization (Ms) of 77.7 emu/g,
remanence magnetization (Mr) of 7.7 emu/g, and coercivity (Hc) of 49 Oe. The X-ray diffraction
pattern showed the inverse cubic spinel structure with an average crystal size of about 20.1 nm.
Fe3O4 magnetic nanoparticles with various concentrations were used to be detected using a GMR
sensor. The output voltage of the GMR sensor with the single and double spin-valve increased from
1.7 to 3.9 mV and 2.9 to 5.3 mV with the increase of the Fe3O4 concentration from 0 to 20 mg/mL,
respectively. |
