Search results for "Giant magnetoresistance"
showing 10 items of 29 documents
Electrical Modeling of Monolithically Integrated GMR Based Current Sensors
2018
We report on the electrical compact model, using Verilog-A, of a monolithically integrated giant magnetoresistance (GMR) based electrical current sensors. For this purpose, a specifically designed ASIC (AMS $0.35\mu \mathrm{m}$ technology) has been considered, onto which such sensors have been patterned and fabricated, following a two-steps procedure. This work is focused on the DC regime model extraction, giving evidences of its good performance and stating the bases for subsequent model improvements.
High spin polarization in Co2CrAl–Cr superlattice
2009
The electronic structure, magnetic properties and interface effects in Co2CrAl?Cr superstructures have been investigated by the use of first principle calculations. The results show that at the interface, a large magnetic moment and a high spin polarization can be induced by a strong ferromagnetic exchange interaction at the Cr?Co interface. However, at the CrAl?Cr interface, both the magnetic moment and the spin polarization of the Cr atoms are decreased due to a Cr?Cr antiferromagnetic interaction. It can also be found that the interface effect is only a short range effect. So, high spin polarization in Co2CrAl?Cr superlattice can be obtained. Based on this theoretical analysis, a large g…
Giant Magnetoresistance (GMR) Magnetometers
2016
Since its discovering in 1988, the Giant Magnetoresistance (GMR) effect has been widely studied both from the theoretical and the applications points of view. Its rapid development was initially promoted by their extensive use in the read heads of the massive data magnetic storage systems, in the digital world. Since then, novel proposals as basic solid state magnetic sensors have been continuously appearing. Due to their high sensitivity, small size and compatibility with standard CMOS technologies, they have become the preferred choice in scenarios traditionally occupied by Hall sensors. In this chapter, we analyze the main properties of GMR sensors regarding their use as magnetometers. W…
Advanced Giant Magnetoresistance (GMR) sensors for Selective-Change Driven (SCD) circuits
2021
Nowadays, bio-inspiration is driving novel sensors designs, beyond vision sensors. By taking advantage of their compatibility with standard CMOS technologies, the integration of giant magneto-resistance (GMR) based magnetic sensors within such event-driven approaches is proposed. With this aim, several topologies of such GMR sensors have been designed, fabricated and characterized. In addition, integrated circuit interfaces of a standard CMOS technology are also proposed. Their suitability for this approach is then demonstrated by means of Cadence IC simulations.
Probing giant magnetoresistance with THz spectroscopy
2014
We observe a giant magnetoresistance effect in CoFe/Cu-based multistack using THz time-domain spectroscopy. The magnetic field-dependent dc conductivity, electron scattering time, as well as spin-asymmetry parameter of the structure are successfully determined.
Magnetic Field Sensors Based on Giant Magnetoresistance (GMR) Technology: Applications in Electrical Current Sensing
2009
The 2007 Nobel Prize in Physics can be understood as a global recognition to the rapid development of the Giant Magnetoresistance (GMR), from both the physics and engineering points of view. Behind the utilization of GMR structures as read heads for massive storage magnetic hard disks, important applications as solid state magnetic sensors have emerged. Low cost, compatibility with standard CMOS technologies and high sensitivity are common advantages of these sensors. This way, they have been successfully applied in a lot different environments. In this work, we are trying to collect the Spanish contributions to the progress of the research related to the GMR based sensors covering, among o…
Analytical compact modeling of GMR based current sensors: Application to power measurement at the IC level
2010
An analytical compact model for giant magnetoresistance (GMR) based current sensors has been developed. Different spin-valve based full Wheatstone bridge sensors, with the current straps integrated in the chip, have been considered. These devices have been experimentally characterized in order to extract the model parameters. In this respect, we have focused on the sensors linear operation regime. The model, which allows the individual description of the magnetoresistive elements, has been implemented in a circuit simulator by means of a behavioral description language: Verilog-A. We also propose the use of the devices in a direct power measurement application at the integrated circuit (IC)…
Sub-mA current measurement by means of GMR sensors and state of the art lock-in amplifiers
2015
Electric current measurement at the range of μA in integrated circuit has been traditionally carried out by micro-electronically engineered systems, such as current mirrors or charging capacitors. However, off-line, i.e., non-intrusive methods provide advantages related to size and power consumption. In this sense, giant magnetoresistance (GMR) magnetic sensors are optimal due to their sensitivity and CMOS compatibility. In this work, we make use of specifically designed CMOS GMR-based current sensors in combination with a custom electronic interface based on a low-voltage low-power lock-in amplifier, demonstrating the capability of this combination for current measurement in the range of μ…
Giant Magnetoresistance (GMR) sensors for 0.35µm CMOS technology sub-mA current sensing
2014
This paper reports on the design and fabrication of microelectronic structures for non-invasive indirect electric current sensing at the IC level. A 0.35 ?m CMOS ASIC has been specifically developed for this purpose. Then, a low temperature post-process, fully compatible with the CMOS technology, has been applied for depositing Giant Magnetoresistive (GMR) sensors. Preliminary experimental results for obtaining the sensitivity of the devices are presented. The detection limit is estimated to be about 5 ?A.