Estudio de dispositivos magnetométricos : aplicación al Proyecto NANOSAT

Se han estudiado, diseñado y desarrollado, con éxito, varios tipos de sensores magnéticos basados en distintos principios: método de fuerzas, efectos cruzados, magnetorresistencia anisotrópica, efectos magneto-ópticos y optoelectrónica, con aplicaciones magnetométricas diferentes: fundamentalmente medidas de momento y de campo magnético. Estos sensores constituyen una aportación a los dispositivos microtecnológicos de caracterización magnética. Dentro de este ámbito se ha trabajado en tres líneas de investigación: · Diseño y desarrollo de un magnetómetro de gradiente alterno y detección óptica para la medida de momento magnético de películas delgadas que son candidatas a ser integradas en MEMS. · Desarrollo de un conjunto de sensores magnéticos híbridos piezoeléctrico-magnetostrictivo orientado a la miniaturización de los mismos. En este campo se ha trabajado tanto en sensores en los cuales el material piezoeléctrico es el inductor de las tensiones mecánicas como en los sensores en los cuales el magnetostrictivo es el inductor de las tensiones mecánicas. Los sensores desarrollados tienen gran sensibilidad, buen coeficiente señal-ruido, y son repetitivos, robustos y económicos para la medida de campo magnético en el rango de 100mT a 100pT. · Como aplicación se ha trabajado en el diseño de la electrónica de acondicionamiento de dos sensores magnéticos embarcados en un nanosatélite español, NANOSAT: un sensor magnético basado en magnetorresistencia anisotrópica (AMR) para el Sistema de Control de Actitud del satélite y un nanosensor magnético basado en el Efecto Faraday de un material nanoestructurado como experimento

Lock-in amplifiers for AMR sensors

Anisotropic magnetoresistive (AMR) magnetic sensors are often chosen as the magnetic transducer for magnetic field sensing in applications with low to moderate magnetic field resolution because of the relative low mass of the sensor and their ease of use. They measure magnetic fields in the order of the Earth magnetic field (with typical sensitivities of 1‰/G or 10−2‰/μT), have typical minimum detectable fields in order of nT and even 0.1 nT but they are seriously limited by the thermal drifts due to the variation of the resistivity with temperature (∼2.5‰/°C) and the variation of the magnetoresistive effect with temperature (which affects both the sensitivity of the sensors: ∼2.7‰/°C, and the offset: ±0.5‰/°C). Therefore, for lower magnetic fields, fluxgate vector sensors are generally preferred. In the present work these limitations of AMR sensors are outlined and studied. Three methods based on lock-in amplifiers are proposed as low noise techniques. Their performance has been simulated, experimentally tested and comparatively discussed. The developed model has been also used to derive a technique for temperature compensation of AMR response. The final goal to implement these techniques in a space qualified applied specific integrated circuit (ASIC) for Mars in situ exploration with compact miniaturized magnetometers

Small Fluxgate Magnetometers: Development and Future Trends in Spain

In this paper, we give an overview of the research on fluxgate magnetometers carried out in Spain. In particular we focus in the development of the planar-type instruments. We summarize the fabrication processes and signal processing developments as well as their use in complex systems and space

Improved understanding of magnetic signatures of basaltic lava flows and cones with implication for extraterrestrial exploration

This work internds to understand the extremely variable and partly very pronounced magnetic anomalies of basaltic cone as a terrestrial analogue of Mars, where very high remanent anomalies have been observed

Effects of gamma-Ray radiation on magnetic properties of NdFeB and SmCo permanent magnets for space applications

Several samples of NdFeB and SmCo permanent magnets have been irradiated with gamma rays up to different total irradiation doses until 1Mrad(Si). Magnetic properties of the samples have been measured at different temperatures before and after irradiation. The modifications of the magnetic parameters are presented. From these results it is highlighted which permanent magnets show more resistance to radiation and are more suitable to be included in devices for space applications or high radiation environments

Small Magnetic Sensors for Space Applications

Small magnetic sensors are widely used integrated in vehicles, mobile phones, medical devices, etc for navigation, speed, position and angular sensing. These magnetic sensors are potential candidates for space sector applications in which mass, volume and power savings are important issues. This work covers the magnetic technologies available in the marketplace and the steps towards their implementation in space applications, the actual trend of miniaturization the front-end technologies, and the convergence of the mature and miniaturized magnetic sensor to the space sector through the small satellite concept

MOURA magnetometer for Mars MetNet Precursor Mission. Its potential for an in situ magnetic environment and surface characterization

MOURA magnetometer and gradiometer is part of the scientific instrumentation for Mars MetNet Precursor mission. This work describes the objective of the investigation, summarizes the work done in the design and development of the sensor as well as its calibration, and shows the demonstration campaigns to show the potential of such instrument for planetary landers and rovers

Constraints on the Spatial Distribution of Lunar Crustal Magnetic Sources From Orbital Magnetic Field Data

International audienceSpacecraft measurements show that the crust of the Moon is heterogeneously magnetized. The sources of these magnetic anomalies are yet not fully understood, with most not being related to known geological structures or processes. Here, we use an inversion methodology that relies on the assumption of unidirectional magnetization, commonly referred to as Parker's method, to elucidate the origin of the magnetic sources by constraining the location and geometry of the underlying magnetization. This method has been used previously to infer the direction of the underlying magnetization but it has not been tested as to whether it can infer the geometry of the source. The performance of the method is here assessed by conducting a variety of tests, using synthetic magnetized bodies of different geometries mimicking the main geological structures potentially magnetized within the lunar crust. Results from our tests show that this method successfully localizes and delineates the two-dimensional surface projection of subsurface three-dimensional magnetized bodies, provided their magnetization is close to unidirectional and the magnetic field data are of sufficient spatial resolution and reasonable signal-to-noise ratio. We applied this inversion method to two different lunar magnetic anomalies, the Mendel-Rydberg impact basin and the Reiner Gamma swirl. For Mendel-Rydberg, our analysis shows that the strongest magnetic sources are located within the basin's inner ring, whereas for Reiner Gamma, the strongest magnetic sources form a narrow dike-like body that emanates from the center of the Marius Hills volcanic complex. Plain Language Summary Magnetometers onboard spacecraft have detected magnetic field signals originating from the lunar crust. These signals are known as magnetic anomalies and are generated by rocks that are permanently magnetized. Lunar magnetic anomalies are distributed heterogeneously over the lunar surface and the geological processes that gave rise to them is under debate. By inferring the shape of the underlying magnetized material, we can constrain these processes and shed light on the Moon's geological history. In this study, we evaluate the ability of a methodology up to now used to infer the direction of the magnetization, to recover the location and shape of the magnetized material. Through a series of tests, we show that this method can constrain the shape of the source of a magnetic anomaly, provided that the respective part of the crust is magnetized along a common direction. We then apply the method to two lunar magnetic anomalies. The inferred shape and location are in good agreement with the associated geological features and suggest that one originated by an impact event and the other by volcanic activity. Future applications can focus on constraining the origin of the many lunar magnetic anomalies that are not associated with visible geological features

Una visión personal sobre la Óptica & Fotónica

Participación en la mesa redonda del I Workshop mujeres en Óptica & Fotónica @SEDOPTICA, 6 de septiembre de 201