Rajesh Kumar Rajagopal

By Rajesh Kumar Rajagopal

Magnetic skyrmions are small whirling topological defects in a texture magnetization state. Their stabilization and dynamics depend strongly on their topological properties. Skyrmions are induced by non-centrosymmetric crystal structure of magnetic compounds and thin films. Skyrmions are extremely small, with diameters in the nanometer range, and behave as particles that can be created, moved and annihilated. This makes them suitable for information storage and logic technologies. Skyrmions had been observed only at low temperature, and mostly under large applied magnetic fields. An intense research in this field has led to the identification of skyrmions in thin-film and multilayer structures in these heterostrutres skyrmions are able to survive at room temperature and can be manipulated by electrical currents. Utilizing interlayer magnetic exchange bias with synthetic antiferromagnet with can be used to isolated antiferromagnetic skyrmions at room temperature. The development of skyrmion-based topological spintronics holds promise for applications in the writing, processing and reading functionalities at room temperature and can be extended further to all-electrical manipulation spintronics.

Part of the book: Magnetic Skyrmions

By Subha Krishna Rao, Rajesh Kumar Rajagopal and Gopalakrishnan Chandrasekaran

Real-time gas sensors, which use chemiresistive metal oxide (MO) semiconductors, have become more important in both research and industry. Fiber optic metal oxide (MO) semiconductor sensors have so increased the utility and demand for optical sensors in a variety of military, industrial, and social applications. Fiber optic sensors’ inherent benefits of lightweight, compact size, and low attenuation were actively leveraged to overcome their primary disadvantage of expensive cost. With the growing need for quicker, more precise, and simpler gas sensing, metal oxide semiconductor gas sensors are focusing on new and novel materials at room temperature. The realization that materials with coexisting magnetic and ferroelectric orders offer up effective ways to alter magnetism using electric fields has drawn scientists from diverse areas together to research multiferroics for gas sensing applications in recent years. The chapter shall encompass a brief summary of the underlying physics related to fiber optic gas sensors and parameters involved in gas sensing, the significance of the fascinating class of metal oxide materials, and an outline of spin frustrated multiferroics for possible applications and its potential possibilities for progress in the future.

Part of the book: Metal-Oxide Gas Sensors