Current technology seeks to develop nanoscale devices capable of storing and processing information. These devices would be difficult to make in the area of electronics, which is based on the manipulation of electric charge. However, thanks to advances in experimental and theoretical physics in the field of condensed matter, these devices are already a reality, belonging to the field of what we now call spintronics, which bases its functionality on the control of the electron’s spin, a property that can only be conceived at the quantum level. In this article we review this new perspective, describing giant- and tunneling- magnetoresistance, the spin transfer torque, and their applications such as MRAM memories, nano-oscillators and lateral spin valves. 

En la actualidad el desarrollo de la tecnología nos ha conducido a elaborar dispositivos nanométricos capaces de almacenar y procesar información. Estos dispositivos serían difíciles de imaginar en la electrónica, la cual se basa en la manipulación de la carga eléctrica del electrón. Sin embargo, gracias a los avances en la física teórica y experimental en el campo de la materia condensada, estos dispositivos ya son una realidad, perteneciendo a lo que actualmente se denomina la electrónica del espín o espintrónica, la cual basa su funcionalidad en el control del espín del electrón, una propiedad que sólo puede ser concebida a nivel cuántico. En el presente artículo revisaremos esta nueva perspectiva, describiendo la Magnetorresistencia Gigante y de Efecto Túnel, la transferencia de momento de espín y sus respectivas aplicaciones como son las memorias MRAM, nano-osci...

Current technology seeks to develop nanoscale devices capable of storing and processing information. These devices would be difficult to make in the area of electronics, which is based on the manipulation of electric charge. However, thanks to advances in experimental and theoretical physics in the field of condensed matter, these devices are already a reality, belonging to the field of what we now call spintronics, which bases its functionality on the control of the electron’s spin, a property that can only be conceived at the quantum level. In this article we review this new perspective, describing giant- and tunneling- magnetoresistance, the spin transfer torque, and their applications such as MRAM memories, nano-oscillators and lateral spin valves. 

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Se construyó un magnetómetro de efecto Kerr superficial (MEKS) para medir las propiedades magnéticas de películas delgadas de Permalloy (Ni81Fe19) de 20 nm de espesor. Se encontró que el campo coercitivo de las muestras tiene valores entre 2-6 Oe. Las películas mostraron anisotropía uniaxial en el plano y se identificaron los ejes de fácil y difícil magnetización. Se midió el ángulo de Kerr para las configuraciones longitudinal y polar y la saturación magnética para diferentes ángulos de incidencia de haz de luz. Los resultados fueron comparados satisfactoriamente con los obtenidos con un Magnetómetro de Muestra Vibrante (MMV).

A surface Kerr effect magnetometer (MEKS) was built to measure the magnetic properties of Permalloy (Ni81Fe19) thin films of 20 nm thickness. It was found that the coercive field of the samples has values between 2-6 Oe. The films showed in-plane uniaxial anisotropy and axes of easy and difficult magnetization were identified. The Kerr angle was measured for the longitudinal and polar configurations and the magnetic saturation for different angles of incidence of the light beam. The results were satisfactorily compared with those obtained with a Vibrating Sample Magnetometer (VSM).

This paper describes the implementation and a detailed optimization of a Vibrating Sample Magnetometer (VSM) for an undergraduate physics course laboratory. The VSM operation parameters were extensively discussed using Foner and Mallison coils configuration. The influence of the involved parameters (e.g. oscillation frequency, oscillation amplitude, rate change of the external magnetic field, coils configuration, etc.) on the induced voltage in the pick-up coils were discussed. A disk of nickel of 6-mm diameter was used for the calibration of the magnetometer, comparing the hysteresis loop measured with our magnetometer with the one obtained using a commercial VSM. Magnetization curves of two different samples were obtained in order to test the sensitivity of the magnetometer. The vibrating sample magnetometer implemented in the present work is able to detect changes in the total magneti...

Este artículo describe la implementación y una optimización detallada de un magnetómetro de muestra vibrante (VSM) para un laboratorio de licenciatura en física. Los parámetros de operación de VSM se discutieron ampliamente usando la configuración de bobinas de Foner y Mallison. Se discutió la influencia de los parámetros implicados (por ejemplo, frecuencia de oscilación, amplitud de oscilación, cambio de velocidad del campo magnético externo, configuración de bobinas, etc.) sobre la tensión inducida en las bobinas de captación. Se utilizó un disco de níquel de 6 mm de diámetro para la calibración del magnetómetro, comparando el bucle de histéresis medido con nuestro magnetómetro con el obtenido utilizando un VSM comercial. Se obtuvieron curvas de magnetización de dos muestras diferentes para probar la sensibilidad del magnetómetro. El magnetómetro de muestra vi...

This paper describes the implementation and a detailed optimization of a Vibrating Sample Magnetometer (VSM) for an undergraduate physics course laboratory. The VSM operation parameters were extensively discussed using Foner and Mallison coils configuration. The influence of the involved parameters (e.g. oscillation frequency, oscillation amplitude, rate change of the external magnetic field, coils configuration, etc.) on the induced voltage in the pick-up coils were discussed. A disk of nickel of 6-mm diameter was used for the calibration of the magnetometer, comparing the hysteresis loop measured with our magnetometer with the one obtained using a commercial VSM. Magnetization curves of two different samples were obtained in order to test the sensitivity of the magnetometer. The vibrating sample magnetometer implemented in the present work is able to detect changes in the total magneti...

In this article we present the results of applying the technique of electrostatic separation to minerals containing rare earths. The presence of La, Ce, Sm, Pr and Nd in the initial sample was verified by ICP-MS analysis. Hematite and non-conductive minerals such as dolomite and feldspar-K were concentrated by electrostatic separation. On the other hand, through SEM-EDS it was proved that the rare earth elements belong to the monazite mineral (La, Ce, Nd) PO4 and that this is associated to Feldspar-K.

In this article we present the results of applying the technique of electrostatic separation to minerals containing rare earths. The presence of La, Ce, Sm, Pr and Nd in the initial sample was verified by ICP-MS analysis. Hematite and non-conductive minerals such as dolomite and feldspar-K were concentrated by electrostatic separation. On the other hand, through SEM-EDS it was proved that the rare earth elements belong to the monazite mineral (La, Ce, Nd) PO4 and that this is associated to Feldspar-K.

En este artículo se presentan los resultados de aplicar la técnica de separación electrostática a minerales que contienen tierras raras. Se verificó la presencia de La, Ce, Sm, Pr y Nd en la muestra inicial mediante análisis de ICP-MS. Por medio de la separación electrostática se concentraron minerales conductores la hematita y no conductores como dolomita y feldespato-K. Por otro lado, mediante SEM-EDS se comprobó que los elementos de tierras raras pertenecen al mineral monacita (La, Ce, Nd)PO4 y que éste se encuentra asociado al Feldespato-K.