چكيده به لاتين
The use of magnetic materials (materials that respond to the magnetic field and its changes) as a sensor of changes in various industries due to the development of nanotechnology has been considered. Due to the advancement of optical fiber technology in recent years because of its light weight, long useful life, small size, high penetration depth and adaptability to a variety of environments, the field of fiber optic magnetic field sensors with special applications in medical sciences, control, earth study and etc. have been considered. Due to the superparamagnetic properties of magnetite nanoparticles and the unique optical properties of graphene oxide, in this research, magnetic field sensors based on light intensity made with graphene-magnetite coating have been investigated. Graphene-magnetite hybrid has been synthesized by simple mixing method due to the presence of different (sign) electrostatic charges in graphene oxide and magnetite. Single-mode optical fibers are tapered by heat-tensile method with manufactured tapering system to diameters of about 3.3 μm to 12.8 μm in tapering lengths from 6.8 mm to 11 mm. By graphene-magnetite coating with drop casting on the tapered region, the sensors are sensitized to a magnetic field with a sensitivity of 98.7 (nW / mT) to 324 (nW / mT) at a laser wavelength of 1550 nm and a magnetic flux density range of 0 to 60 mT. Calibrated magnetic field is applied by magnetic coils. Analysis of SEM, TEM, image processing, setup layout and results have also been reviewed.
According to the experiments, increasing the length of the tapered area has a linear effect on increasing the sensitivity of the sensors because due to the magnetic properties of graphene oxide and magnetite nanoparticles, more interaction with the evanescent field and the environment is created but the output power of sensors with increasing of tapering length has an exponential-decreasing relationship and the limitation of the sensitivity of the power sensor will be the limiting factor of increasing the length. Also, by reducing the diameter of the tapering, due to the greater penetration of the evanescence field, the sensitivity of the sensors increases. Due to the use of light power measurement, manufactured sensors are economically feasible and can be used as sensors to detect objects, determine the magnetic properties of materials, magnetic biomaterials detection, magnetic anomaly detection, optical teslameter and etc. in the aerospace, oil and gas, medical equipment, mines and etc. industries.
