Transmission Electron Microscopy in Micro-nanoelectronics

Chapter 5

Magnetic Mapping Using Electron Holography

5.1. Introduction

The recent know-how in manipulating the spin of electrons combined with their charge to transfer information has opened new routes in so-called “spintronic” devices that already have found applications in data storage and magnetic sensors hyper-frequency generators and have high potentialities in logics devices [CHA 07]. Similar to microelectronic compounds in which the size reduction induces remarkable properties, magnetic nanosystems exhibit various potential opportunities. Magnetic materials (3D types and magnetic semiconductors) are, therefore, largely used in the microelectronic industries in hybrid systems combined with “normal” silicon devices. Likewise, microelectronic devices that require the knowledge of their structural and chemical properties and also of the local electrical potential, strain field, etc., the local magnetic properties of spintronic systems need to be determined to optimize their use as well. Electron microscopy has proved to be an efficient tool for such goals and transmission electron microscopy (TEM) has been used by several groups worldwide in the analysis of magnetic nanomaterials and systems [TON 92, RAF 98, RAF 00, RAF 02, McC 97, McC 98, BEL 03, SNO 03, SNO 08].

As presented in Chapter 1, the phase of an electron wave interacting with a sample is sensitive to the electrostatic, magnetic and strain fields within the specimen and possibly around it. However, in a conventional ...