Seeing magnons at spin-to-charge conversion interfaces

在过去的几十年里，半导体器件已经彻底改变了科学和技术。它们基于在微米上控制电子电荷传输的能力，并且越来越多地是纳米级的。晶体管（逻辑器件的构建块）的持续尺寸缩放正在达到瓶颈，热管理和速度达到物理极限。自旋电子器件是一类利用电子自旋和电荷的器件，被认为具有克服电子学当前挑战的潜力。实现自旋输运的一种方法是基于磁振子的产生和传播，磁振子是携带自旋动量的自旋波。这些自旋电流可以在磁振子产生磁性材料的界面处转换为电荷电流，其中重金属如铂，在那里它们由温度梯度驱动。理解在这个界面上的电荷-自旋和自旋-电荷转换现象对于新兴的热自旋电子学和自旋热电子学领域以及新电子器件的设计是基础。在这个项目中，我们提出了一种方法来检测和映射磁振子，通过利用现代最先进的电子显微镜的突破性能力。本计画将提供一种新的方法来研究各种材料与元件结构中的磁序与自旋波激发的基本原理。结合分析电子显微镜可以提供的额外丰富的信息，如局部原子结构和化学，这种方法将提供材料和设备的磁性和电子特性的完整图片。

Semiconductor devices have revolutionised science and technology in the past decades. They are based on the ability to control the transport of electron charges on the micrometer, and increasingly the nanoscale. The continuous size scaling of transistors - the building blocks of logic devices - is reaching a bottleneck, with heat management and speed reaching physical limits. Spintronic devices is a class of devices which utilises the spin of the electron in addition to its charge, which are believed to have the potential to overcome current challenges in electronics. A way to achieve spin transport is based on the generation and propagation of magnons, spin waves which carry spin momentum. These spin currents can be converted to charge currents at interfaces of magnon generating magnetic materials, with heavy metals such as platinum, where they are driven by temperature gradients. Understanding the phenomena at the charge-to-spin and spin-to-charge conversion at this interface is fundamental for the newly emerging fields of thermal spintronics and spin caloritronics and the design of new electronic devices. In this project we propose a method to detect and map magnons, by exploiting the ground-breaking capabilities of modern state-of-the-art electron microscopes. This project will provide a new way of studying the fundamentals of magnetic ordering and spin wave excitations in a variety of materials and device structures. Combined with the added wealth of information that analytical electron microscopy can provide such as local atomic structure and chemistry this methodology will provide a complete picture of magnetic and electronic properties of materials and devices.