Steel 110G13L. Thermomagnetic and Galvanomagnetic Effects in its Films

The article shows the ability to control magnetic properties due to modulation of phases in the film with varying temperature of growth. So, at low growth temperatures, a film is formed with an axis of easy magnetization in plane. An increase in temperature leads to a change in the phase composition of the film. It is shown that the presence of even a small component of the magnetization vector in the perpendicular direction leads to the appearance of a thermomagnetic effect of a large magnitude with respect to thermal noise

STUDY OF THE MAGNETO-RESISTANCE SILICON P-TYPE

The study of galvanomagnetic phenomena in silicon, in strong magnetic fields, is associated with great difficulties due to the high resistance of the samples and the complexity of preparing omics contacts that work well in a wide range of temperatures and magnetic fields. Therefore, until now, all existing data on galvanomagnetic effects in silicon have been obtained only in the region of weak magnetic fields. Given the growing interest in silicon due to its large potential, it seemed appropriate to study the galvanomagnetic effects in the region of strong magnetic fields, where quantum effects play the dominant role. The study of Galvano-magnetic effects (as well as tensoeffects) in silicon under extreme conditions allows not only to identify the mechanisms of these effects, but also to identify the possibility of creating gaussmeters, infrared detectors, sensitive strain gauges, amplifiers and generators of a wide frequency range. Keywords: galvano-magnetic effects, silicon, negative magnetoresistance, uniaxial pressure.

Factibilidad de integrar split-drain MAGFETs con alta sensibilidad en tecnología CMOS

Factibilidad de integrar split-drain MAGFETs con alta sensibilidad en tecnología CMOS Feasibility to integrate high-sensitivity split-drain MAGFETs in CMOS technology Gerard Franz Santillán Quiñonez, Víctor H. Champac Vilela y Roberto S. Murphy Arteaga Departamento de Engenharia Elétrica, Universidade Federal de Santa Catarina, Campus UniversitárioTrindade, Florianópolis, Santa Catarina, Brasil, C.P. 88040900, e-mail: [email protected] Departamento de Electrónica, Instituto Nacional de Astrofísica, Óptica y Electrónica, Sta. Ma. Tonantzintla, Puebla, México, C.P. 72840. DOI: https://doi.org/10.33017/RevECIPeru2011.0015/ RESUMEN La factibilidad de un Split-Drain MAGFET como sensor magnético ha sido explorada con diversas metodologías, pero sin aprovechar más de un efecto galvanomagnético simultáneamente. Unificando trabajos realizados teórica y experimentalmente, modelos analíticos continuos para la relación entre las fuerzas actuando en la dirección de deflexión y el ángulo de Hall, así como criterios de diseño para incrementar la sensibilidad de un Split-Drain MAGFET son presentados. El análisis propuesto muestra que es posible aprovechar los efectos de deflexión de las líneas de corriente y de magnetorresistencia para incrementar la sensibilidad en un Split-Drain MAGFET. Con un Split-Drain MAGFET con canal considerado como plato de Hall corto, sensibilidades de hasta 59 %/T han sido obtenidas experimentalmente midiendo densidades de flujo magnético desde 90 µT hasta 275 µT. Esto es posible debido a la contribución de los dos efectos galvanomagnéticos considerados. Adicionalmente, un macro modelo SPICE para un Split-Drain MAGFET es propuesto para facilitar su uso en circuitos de mayor complejidad. Con respecto a los resultados experimentales obtenidos, el macro modelo SPICE propuesto tiene un error <1.6 % generando el desbalance entre las corrientes de drenaje. Como un Split-Drain MAGFET es compatible con tecnología CMOS, dominante en circuitos integrados, los resultados obtenidos muestran que es factible usarlo como sensor magnético en sistemas integrados CMOS de alta complejidad, lo cual puede abrir un amplio rango de aplicaciones con bajo costo. Descriptores: MAGFET, split-drain MAGFET, efectos galvanomagnéticos, efecto Hall, magnetorresistencia, sensor magnético. ABSTRACT The feasibility of a Split-Drain MAGFET as magnetic sensor has been explored with several methodologies, but without simultaneously advantaging more than one galvanomagnetic effect. Unifying theorically and experimentally developed works, continuous analytical models for the relationship between forces acting in the deflection direction and for the Hall angle, as well as design criteria to increase the sensitivity of a Split-Drain MAGFET are presented. The proposed analysis shows that it is possible to take advantage of the current-lines deflection and magnetoresistance effects in order to increase the sensitivity of a Split-Drain MAGFET. With a Split-Drain MAGFET with a channel considered as a short Hall plate, sensitivities up to 59%/T have been experimentally obtained measuring magnetic flux densities from 90 µT to 275 µT. This is possible due to the contribution of the two considered galvanomagnetic effects. Additionally, a SPICE macro model for a SplitDrain MAGFET is proposed to facilitate its use in more complex circuits. With respect to the obtained experimental results, the proposed SPICE macro model has an error <1.6 % generating the drain current imbalance. Since a Split-Drain MAGFET is compatible with CMOS technology, dominating in integrated circuits, the obtained results show that it is feasible to use it as magnetic sensor in CMOS integrated systems of high complexity, which opens a wide range of low cost applications. Keywords: MAGFET, split-drain MAGFET, galvanomagnetic effects, Hall effect, magnetoresistance, magnetic sensor.

Anomalous Galvanomagnetic Effects due to Spontaneous Spin Polarization of Electrons in Crystal with Low Concentration of 3d-Transition Element Impurities

The results of experimental observations at room temperature of anomalous Hall effect associated with existence of a spontaneous spin polarization of conduction electrons in mercury selenide crystals doped with chromium and vanadium in the concentration range from 1·1018 to 1·1019 sm-3 are reported. Comparison of the experimental data together with the previously reported results related to crystals with iron, cobalt and nickel impurities shows that the relative contribution to the anomalous Hall effect is maximal for vanadium impurity (≈ 13%) and minimal for iron impurity (≈ 5%). Also, transverse magnetoresistance with a characteristic dependence on the magnetic field strength, on which an unusual hysteresis in the field dependence was observed, was found in investigated crystals at room temperature. Theoretical interpretation of the observed effects is developed based on the concepts of thermodynamic nature of anomalous galvanomagnetic phenomena in electron systems with spontaneous spin polarization.