ACADSTAFF UGM
| Title | : | Detection of Fe3O4/PEG nanoparticles using single and double spin valve GMR sensing elements in Wheatstone bridge circuit |
| Author | : |
Dr.Eng. Edi Suharyadi, S.Si., M.Eng. (1) |
| Date | : | 6 2020 |
| Keyword | : | Magnetic nanoparticles, Spin valve, Giant magnetoresistance (GMR), Sensor, Fe3O4. Magnetic nanoparticles, Spin valve, Giant magnetoresistance (GMR), Sensor, Fe3O4. |
| Abstract | : | The simple Wheatstone bridge-giant magnetoresistance (GMR) sensor with single and double spin-valve thin films had been successfully developed for detecting Fe3O4/PEG magnetic nanoparticles. Spin valve thin films with structure of [Ta (2nm)/Ir20Mn80 (10nm)/Co90Fe10 (3nm)/Cu (2.2nm)/(Co90Fe10)92B8 (10 nm)/Ta (5 nm)] were fabricated using RF magnetron sputtering on silicon substrates with 500 nm-thick surface oxide layer. Invers spinel structured magnetite (Fe3O4) nanoparticles and Fe3O4 coated with the polyethylene glycol (PEG) were synthesized by coprecipitation methods. The particles size of Fe3O4 nanoparticles was 11.0 nm and 12.5 nm after coating with PEG. The saturation magnetization (Ms) of Fe3O4 was 77.0 emu/g and decreased after coating with PEG to 49.6 emu/g, which is due to the paramagnetic properties of PEG. The coercivity (Hc) of Fe3O4 was 51.2 Oe and increased after coating with PEG to 61.5 Oe, which is due to the increase of particle size after coating with PEG. The change of output voltage of the GMR sensor with the single and double spin valve for Fe3O4 was 2.2 and 5.5 mV, respectively, and then decreased to 1.4 and 1.5 mV for Fe3O4/PEG, respectively. The decrease of the output voltage was caused by the decrease of saturation magnetization of Fe3O4 after coating with PEG. |
| Group of Knowledge | : | |
| Level | : | Internasional |
| Status | : |
Draft
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