| Summary: | 碩士 === 國立雲林科技大學 === 材料科技研究所 === 102 === This study focused on the system of magnetic tunnel junctions (MTJ) embedded with Co、Fe magnetic nanoparticles. By controlling the deposition rate and thickness of iron and cobalt films, we fabricated the small iron and cobalt nanoparticles embedded within the MgO la yer. The magnetic properties were measured by physical property measurement system and alternating gradient magnetometer (AGM). The samples with and temperatures annealing various thicknesses were then patterned into devices. The magnetoresistance of the device measured by four-point-probe and CAFM(Conductive Atomic Force Microscopy) methods. The results show that the sputtering rates had less effect on magnetic properties for same thickness of iron (or cobalt) single magnetic layer. MTJ that are produced containing Co nanoparticles in MgO insulating layer by method of stack, the magnetic properties is unrelated with Co sputtering power. The Ms, Hc are increased by using the second-stage temperature annealing method. In the cases of embedded cobalt films with thickness 0.3 nm, the MTJs still possess with good Double Loop and squareness .
The insertion of iron and cobalt nanoparticles in MTJs affects magnetoresistance (MR) definitely. Inserted of 0.1 nm iron and 0.3nm thickness of cobalt film can increase the MR ratio from 11% up to 111.2% and 325% individually.
Keywords：perpendicular magnetic anisotropy, granular films, magnetic tunnel junction
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