Ferrofluid thin films as optical gaussmeters proposed for field and magnetic moment sensing

Abstract

Ferrofluids belonging to the series, Ni x Fe 1−x Fe 2 O 4 and Zn x Fe 1−x Fe 2 O 4 , were synthesized using cold co-precipitation. Liquid films of these ferrofluids were prepared by encapsulating the ferrofluids in between two optically smooth and ultrasonically cleaned glass plates. Magnetic field induced laser transmission through these ferrofluid films has been investigated. Magnetic field values can be calibrated in terms of output laser power in the low field region in which the variation is linear. This set up can be used as a cheap optical gaussmeter in the low field regime. Using the same set-up, the saturation magnetization of the sample used can also be calculated with a sample that is pre-characterized. Hence both magnetization of the sample, as well as applied magnetic field can be sensed and calculated with a precalibrated sample.

The quantum field of a magnet shown by a nanomagnetic ferrolens

“…11 below (all data measurements and excel graph can be found in this link 5 for download,). [11,12] by the external magnetic field induced. Light dispersion effects [13] are also kept minimal due to the 50 microns or less transparent thin film and the two parallel optic-quality glasses used in the ferrolens which will mostly cancel out any small dispersion they may have.…”

Recent progress in ferrofluids research: novel applications of magnetically controllable and tunable fluids

“…As mentioned in the previous section, ferrouids can have signicant transparency in connement, making them suitable for use in magneto-optic sensors, such as to determine the intensity of a magnetic eld with great sensitivity. 134,135 This effect was also used by Ji et al 136,137 who proposed a v-shaped groove and capillary tube to measure intensity of magnetic elds. The variation in ferrouid transmissivity with temperature under a uniform magnetic eld intensity has been used to sense temperature in ferrouid thin lms, 138 with good sensitivity for temperatures greater than 60 C. Variation in the optical properties of ferrouids have also been used to measure ammonia with sensitivity of parts per million.…”

Optical Properties of Fe3O4Magnetic Fluid from Iron Sand

“…The phenomenon of polarization angle rotation happens through Faraday effect. Generally, Faraday effect is expressed as  = V×H×I, where V is constant of Verdet material, H is the given magnetic field, and I is the length of the optical path or the thickness of Fe 3 O 4 magnetic fluid [21]. Physically, the polarization angle rotation causes the increase of light intensity since the magnetic field interaction of the light wave with the external static magnetic field given to Fe 3 O 4 magnetic field as a magneto-optic effect.…”