Investigating the magnetic manipulation of the terahertz emission from spintronic structures.

The emission of extremely broadband electromagnetic radiation spanning from the mid- to far-infrared spectral regime from simple bilayer ferromagnetic/heavy metal bilayer structures has opened up exciting possibilities to a new route for the generation of single-cycle pulses of terahertz (THz) radiation. The overarching aim of this research project is to optimise spin-based ferromagnetic structures for the emission of THz radiation and to reveal the physics that governs the properties of these novel systems. By understanding the fundamental emission process, this work has the potential to directly influence the development of future commercial applications for THz radiation and to establish new characterization tools for use in developing the next generation of spintronic devices.

The particular focus of this PhD is an investigation into the magnetic manipulation of the THz emission from spintronic sources, in particular the below magnetic saturation behaviour of spintronic bilayer structures, to develop our fundamental understanding of how the applied magnetic field controls the magnetization across the plane of the spintronic structure and how this in turn controls the THz emission characteristics. This is of particular relevance to novel THz emission schemes utilizing magnetic field shaping for source polarization control. The origin of the reported strong longitudinal THz component from a spintronic structure within a field shaping setup will also be a particular area of investigation, with the potential to develop THz propagation modelling to complement the experimental measurements.

This PhD will involve the use of laser spectroscopy techniques, high power laser amplifier systems and computerized data acquisition packages. Full training will be provided to the student to build competence and expertise in the use of these systems. The student will develop familiarity with spintronic-based THz emitters and THz detection systems and the design and construction of a polarization resolved electro-optic THz detection setup will be a key step in this work. The student will be fully supported in developing the skills essential to early career researchers, including preparation and submission of first author papers for publication of progress in this work in high impact journals and in the delivery of presentations at key national and international conferences (for example MMM-Intermag and IRMMW-THz), thus meeting the remit of EPSRC to train the next generation of skilled researchers.

This project relates to the following EPSRC research areas:
Condensed matter: magnetism and magnetic materials
Photonic materials
RF and microwave devices
Spintronics