Magnetic sensors and geometrical magnetoresistance: A review

Abstract

Magnetic sensing devices are of the extremely significant kind of detectors, that are used several important and useful applications. Geometrical extraordinary magnetoresistance (EMR) is the geometrical kind of magnetoresistance associated with the non-magnetic semiconductor-metal hybrid structure and influenced by geometrical shape. As a result of Lorentz force, the current path change from metal (in absence of magnetic field) to semiconductor (under the subjection of the magnetic field) in semiconductor-metal hybrid structure is the key of EMR phenomena, i.e. once the metal is placed in a semiconductor, it works as a short circuit with the majority of applied current moving through metallic inhomogeneity and the almost whole resistance of semiconductor-metal hybrid structure drops to value smaller than that of homogeneous semiconductor in absence of magnetic field, in other hands, applying of magnetic field alters the current route to be around the metallic inhomogeneity where it works as an open circuit and the whole resistance turns into a quite high magnitude relies on the geometrical form of a device. The variables govern these phenomena are metal and semiconductor conductivity, semiconductor charge carriers mobility, and device geometry. Within this review, EMR phenomena history, variables governed it, materials, and applications of EMR devices are overviewed.

Preparation of Hydroxyapatite from Buffalo Bone and its Biodegradable Nanocomposite with Poly(Butylene Adipate‐co‐Terephthalate)

“…The EDX analysis showed that the calcium to phosphorous (Ca/P) ratio varies from 1.67 to 1.70, which is in good agreement with the standard value (1.4-2.4 Ca/P ratio of stable HAp). [4,47] This confirms that the HAp obtained can be regarded as a bone-like apatite. [34,43] The morphology and in-depth HAp structure were studied by FE-SEM analysis.…”

“…[41] The medium absorbance peak at 632.65 cm −1 indicates the deformation and vibrational mode of the OH group present in HAp. [44][45][46][47] The presence of phosphate group and hydroxyl group in FTIR spectra implies that HAp is present in the calcined powder.…”

Sol-Gel/Gel Casting Nanoarchitectonics of Hybrid Fe2O3–ZnO/PS-PEG Nanocomposites and Their Optomagnetic Properties

“…This behavior is attributed to the low concentration of the magnetic center in the sample (Fe 3+ ), and the diamagnetic polymer between the magnetic center resists the interaction between the magnetic centers. Therefore a diamagnetic behavior is observed in sample PPFe-7Zn [43][44][45][46].…”

Optimization of Magnetic Tunnel Junction Structure through Component Analysis and Deposition Parameters Adjustment

“…The magnetoresistive effect involves a change in the electrical resistance of a structure when a magnetic field is applied. This variation is quantified by the magnetoresistance ratio (MR) and can occur in non-magnetic semiconductor–metal hybrid structures [ 2 ], metals [ 3 ], and magnetic metals [ 4 ] or in multilayer systems such as magnetic tunnel junctions (MTJs) and giant-magnetoresistance, colossal-magnetoresistance, and extraordinary-magnetoresistance structures. Among magnetoresistive structures, those based on the tunnel magnetoresistance effect have a higher MR and better spatial resolution [ 5 , 6 , 7 ], which recommends them for various applications [ 8 , 9 , 10 ].…”