Integration of GMR Sensors with Different Technologies

Abstract

Less than thirty years after the giant magnetoresistance (GMR) effect was described, GMR sensors are the preferred choice in many applications demanding the measurement of low magnetic fields in small volumes. This rapid deployment from theoretical basis to market and state-of-the-art applications can be explained by the combination of excellent inherent properties with the feasibility of fabrication, allowing the real integration with many other standard technologies. In this paper, we present a review focusing on how this capability of integration has allowed the improvement of the inherent capabilities and, therefore, the range of application of GMR sensors. After briefly describing the phenomenological basis, we deal on the benefits of low temperature deposition techniques regarding the integration of GMR sensors with flexible (plastic) substrates and pre-processed CMOS chips. In this way, the limit of detection can be improved by means of bettering the sensitivity or reducing the noise. We also report on novel fields of application of GMR sensors by the recapitulation of a number of cases of success of their integration with different heterogeneous complementary elements. We finally describe three fully functional systems, two of them in the bio-technology world, as the proof of how the integrability has been instrumental in the meteoric development of GMR sensors and their applications.

Pushing down the lateral dimension of single and coupled magnetic dots to the nanometric scale: Characteristics and evolution of the spin-wave eigenmodes

“…Thanks to the advances in nanofabrication and miniaturization, magnetic devices based on single-or multi-layered constitutive elements, with lateral dimensions as small as a few tens of nanometers and with either shape or intrinsic magnetic anisotropy, are routinely produced for current or forthcoming applications. 1,2 These include giant-magnetoresistance (GMR) sensors and read heads 3 , magnetic memory cells 4,5 and bit-patterned hard-disks 6 , spin-torque nano-oscillators 7 and nanomagnetic logic circuits, 8,9 artificial spin-ices 10,11 and magnonic crystals 12 . From the quasi-static point of view, the behavior of each of these small objects can be generally accounted for by assuming a unique magnetization vector (macro-spin approximation), but this simplified picture is not suitable to describe their high-frequency properties.…”

Magnetoresistive Sensor Development Roadmap (Non-Recording Applications)

“…The global vision of new MR sensor (non-recording) applications, products and services was launched out through the next 15 years and beyond. Magnetic field detection has tremendous impact on a large variety of applications and industries [8,9,[11][12][13][148][149][150][151][152], which exploit a wide range of physical phenomena and principles [7,[153][154][155][156][157][158][159][160][161][162][163][164][165][166][167]. To obtain an overview of magnetic field sensing techniques, an analysis of statistics of common magnetic sensors from 1975 to 2017 in the selected patent databases is shown in Figure 3.…”

“…In the field of magnetic field sensing, magnetoresistive (MR) [1][2][3][4] sensors have attracted much interest owing to their high sensitivity, low cost, low power consumption, and small size [5][6][7][8][9][10][11][12][13]. The technological progress of MR sensors has resulted in a wide range of sensor applications, products, and services.…”

Disposable Sensors in Diagnostics, Food, and Environmental Monitoring

“…Thermometric sensors include but not limited to thermocouples, resistance thermometers, thermistors and diodes. In contrast, magnetic methods (such as Hall effect or magnetoresistance) are rarely used in the construction of disposable sensing devices ( Figure ); however, there is some promising ongoing research in this field . For instance, in giant magnetoresistance sensors, binding of magnetic nanoparticles (as reporters of a biological event) onto the surface of a sensor leads to a change in its electrical resistance, enabling rapid and real‐time quantification of biomolecules …”