Study on graphene-based nanocomposites with special magnetoresistance properties
type: CreativeWork
description: Magnetoresistance (MR) refers to the change of a material’s electrical resistance under the presence of an external magnetic field. The discovery of new MR phenomena (e.g., giant magnetoresistance (GMR) and tunneling magnetoresistance (TMR)) since the 1980s initiates the revolution of novel electric devices in the fields of data storage, position sensing, current sensing, non-destructive monitoring, biomedical sensing systems, etc. However, current devices display inadequate MR at the low magnetic field/room temperature, limited working range, and bulky size, which hinders the further application of MR sensors/devices. Therefore, the main goal of this thesis is to develop two-dimensional MR materials with high performance and their potential applications. First, a new hybrid nanosheet was designed and developed by integrating reduced graphene oxide (rGO) and FeCo nanoparticles (NPs). A facile solvothermal process was developed to produce FeCo/rGO hybrid nanosheets with significant MR (21 ± 6%) at the low magnetic field (10 kOe) and room temperature. In addition, we demonstrated that the wireless magnetic field sensing system with FeCo/rGO hybrid nanosheets and ZigBee radio modules was able to achieve real-time detection and data collection of a working mobile phone. By adjusting the mass ratio of rGO adding to the system, we obtained the tunable MR of FeCo/rGO hybrid nanosheets. On the other hand, it was found that the formation of Co-Mn oxides NPs on rGO hybrid nanosheets was increased as the mass ratio of rGO added in the reaction exceeded 50 wt.%. The effects of imported ions on the MR of hybrid nanosheets were investigated. The formation of Co-Mn oxides NPs on hybrid nanosheets in this solvothermal process could lead to relatively high MR (3.5% ~ 4.5%) compared with other structures containing Co and Mn under the same conditions. In addition to the chemical synthesis, we constructed FeCo/rGO hybrid nanosheets by using a laser-assisted physical deposition process…
abstract: Magnetoresistance (MR) refers to the change of a material’s electrical resistance under the presence of an external magnetic field. The discovery of new MR phenomena (e.g., giant magnetoresistance (GMR) and tunneling magnetoresistance (TMR)) since the 1980s initiates the revolution of novel electric devices in the fields of data storage, position sensing, current sensing, non-destructive monitoring, biomedical sensing systems, etc. However, current devices display inadequate MR at the low magnetic field/room temperature, limited working range, and bulky size, which hinders the further application of MR sensors/devices. Therefore, the main goal of this thesis is to develop two-dimensional MR materials with high performance and their potential applications. First, a new hybrid nanosheet was designed and developed by integrating reduced graphene oxide (rGO) and FeCo nanoparticles (NPs). A facile solvothermal process was developed to produce FeCo/rGO hybrid nanosheets with significant MR (21 ± 6%) at the low magnetic field (10 kOe) and room temperature. In addition, we demonstrated that the wireless magnetic field sensing system with FeCo/rGO hybrid nanosheets and ZigBee radio modules was able to achieve real-time detection and data collection of a working mobile phone. By adjusting the mass ratio of rGO adding to the system, we obtained the tunable MR of FeCo/rGO hybrid nanosheets. On the other hand, it was found that the formation of Co-Mn oxides NPs on rGO hybrid nanosheets was increased as the mass ratio of rGO added in the reaction exceeded 50 wt.%. The effects of imported ions on the MR of hybrid nanosheets were investigated. The formation of Co-Mn oxides NPs on hybrid nanosheets in this solvothermal process could lead to relatively high MR (3.5% ~ 4.5%) compared with other structures containing Co and Mn under the same conditions. In addition to the chemical synthesis, we constructed FeCo/rGO hybrid nanosheets by using a laser-assisted physical deposition process…
author: Yang, Songlin
language: en_ca
keywords: Magnetoresistance (MR), reduced graphene oxide (rGO), magnetic field sensor, FeCo nanoparticles, nanocomposite hydrogel
date published: 2021-07-14
date modified: 2026-07-27T21:56:01Z
provider: Western University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: The University of Western Ontario

PropertyValue
property ID: Handle
value: https://hdl.handle.net/20.500.14721/31170