Spintronics

Gas detection sensor

This team of researchers in Cimav developed a gas emission control device. This technology detects toxic gases such as carbon monoxide and carbon dioxide, as well as nitrogen-based gases. In this work the researchers used ethanol as the testing gas to evaluate the sensitivity of the sensor device.

The device may be implemented in laboratories or in industries requiring the control of the emanation of toxic gases, it could be even possible to use sensors in vehicles to prevent them from starting if they detect that the driver has ingested and surpassed a specific alcohol level.

This device allows the detection of gas emanation concentrations in the order of parts per million (ppm). It is elaborated from tin oxide (SnO2) nanowires with diameters of a few teens of nanometers. Tin oxide is selected due to its thermodynamic and chemical stability. The technique used by the researchers in Cimav enables the production of more sensitive and cheaper devices.

The use of nanowires increases the surface area, and thus the device’s sensitivity. Taking advantage of the benefits of nanotechnology allows the manipulation of the material properties to elaborate enhanced performance devices. In this sense the detector developed by the team in Cimav shows a significant increase of sensibility respect other previously manufactured devices.

This project is currently in the process of obtaining two patents. The first corresponds to the method for the low-cost and and simple route fabrication of the sensor.

The second patent is related to a chemical process, which produces an enhancement of the device’s sensibility by five times. This process enables an increase in sensibility in semiconductor oxide-based sensors synthetized in form of nanoparticles, nanowires, microparticles or even porous films.

In this same research topic, on other objective of Cimav’s specialists is to study the magnetic properties of SnO2 nanowires through cobalt doping, which is a ferromagnetic metal. The researchers try to introduce ferromagnetism in the nanowires in such a way they may have applications in microelectronics for the fabrication of devices such as non-volatile Magnetic Random Access Memories (MRAM) and spin-transistors.

Thin Films: Spintronics

A different project conducted by this team of specialists is related to the development of thin films of nanometric thickness with magnetic properties elaborated through sputtering technique. The main objective is to develop new functional materials for their application in electronic devices, especially non-volatile MRAM, which allows non-volatile data storage even in the absence of power supply.

The team of researchers in Cimav seeks to develop ultra-thin films where the electron charge and its spin freedom are exploited. This branch of electronics is called spin electronics or spintronics and allows the fabrication of innovative devices with the capacity of storing and processing data simultaneously. There lies the relevance of thin films with magnetic properties. Computer integrated circuits and processors are fabricated from stacking thin films and using advanced lithography techniques.

Throughout the research projects, the team of specialists in Cimav has subjected the magnetic materials to compressive and tensile deformations and doping with small amounts of non magnetic materials in order to manipulate the thin film properties as needed. In the case of Mn-Ga alloys they tried to reduce magnetization while in Mn-Ge alloys they tried to raise the temperature at which a material is still magnetic (Curie temperature), this aimed at the application of materials to the fabrication of non-volatile MRAM. The results from these projects will contribute knowledge for the microelectronics industry through the production of patents.

This project has been conducted in collaboration with scientists from national and international institutions. Researchers at the Massachusetts Institute of Technology (MIT) in the United States are characterizing the film magnetic domain shape using magnetic force microscopy techniques and at the Universidad de Castilla-La Mancha, in Spain, a team is measuring magnetic properties with a high-resolution equipment.

The general outcomes of this team’s projects have managed to generate publications in international journals and to train highly-specialized human resources.