ANALISA MAGNETORESISTANCE BERBASIS LAPISAN GIANT MAGNETORESISTANCE (GMR) PADA NANOPARTIKEL COBALT; FERRITE (CoFe2O4) DILAPISI POLYETHYLEN GLICOL (PEG) MAGNETORESISTANCE ANALYSIS BASED THIN FILM GIANT MAGNETORESISTANCE (GMR) ON POLYTHYLEN GLICOL (PEG) COATED COBALT FERRITE NANOPARTICLES

Susanti, Novi, Edi Suharyadi

2015 | Disertasi | FMIPA

Magnetoresistance measurements were carried out in a thin film of the spin valve GMR structure CoFeB / Cu / CoFe / MnIr by varying the thickness of the barrier layer of Cu (2,2 and 2,8 nm) and CoFeB free layer (7 and 10 nm) using System Four Point probe Method (SFPPM) in the external field 0-600 Gauss. It was found that the changes in the resistance range were (69,29 – 71,74) ? for Cu 2,2 nm and (38,5 – 40,47) ? for Cu 2,8 nm. In variations of CoFeB thickness, the changes in the resistance range for the thickness of 7 nm and 10 nm were (38,74 to 41,11) ? and (69,29 – 71,74) ? respectively. Furthermore, a thin layer is used as a magnetic sensor to detect the presence of CoFe2O4 nanoparticles, PEG coated CoFe2O4 and CoFe2O4 modified by PEG that was bonded with formalin biomolecules. A shift in resistance value occurs when a thin layer of the coated magnetic nanoparticles. This suggests that the thin layer of the GMR is able to detect the behavior of magnetic spins of CoFe2O4 magnetic nanoparticles.

Kata Kunci : Giant magnetoresistance; thin film; CoFe2O4 nanoparticles; polyethylen glycol