Control of the opto-magnetic properties of alloys by laser and ion irradiation - COLASION

• Applicants: Rantej Bali, Ph.D.; Professor Dr. Alexander Horn
• Subject Area: Synthesis and Properties of Functional Materials ; Coating and Surface Technology ; Experimental Condensed Matter Physics
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 554722570

Recently it has been observed that single-pulsed fs laser irradiation as well as penetrating ions can cause nearly identical changes to the lattice ordering of alloys resulting in the transformation of an initially disordered lattice into an ordered lattice. In certain alloys, such as the prototype Fe60V40, the atomic reordering is accompanied by the onset of ferromagnetism. This project aims to comprehensively characterize the physical limitations and individual advantages of both laser- and ion-induced atomic reordering, and to control the functional properties of initially disordered Fe60V40 for technical applications. To achieve this, we will investigate both laser and ion irradiation by varying the irradiation parameters and analyzing the results by ex situ and in situ metrology coupled with modeling. The methodology will be as follows: Fe60V40 films of varying thicknesses will be irradiated by laser radiation and ion beam with different parameters. Atomic reordering and the concomitant magnetic effects will be characterized using magneto-optic imaging as well as nanoscale structural and holographic imaging. This will allow the determination of the magnetization threshold as a function of the varying laser, ion and sample parameters, and thus find out the physical and technical limitations for achieving laser induced magnetization. In situ time-resolved metrology and modeling will provide further insights into the transient dynamic processes leading to the final reordered atomic structure, such as heating, melting, subsequent cooling, and re-solidification. Additionally, we will investigate the possibility to control the opto-magnetic properties further by applying sequential and multi-pulse irradiation. Sequential irradiation will help us investigate the effects of laser irradiation on the opto-magnetic properties of ion-pre-irradiated Fe60V40 to understand the combined influence of both treatments. By using multi-pulse laser irradiation, we will study the impact of multiple laser pulses on both laser- and ion-pre-magnetized Fe60V40, including the potential for magnetization reversal. We aim to select the appropriate reordering process to achieve desired functional properties by understanding the spatial and temporal limitations of laser- as well as ion-induced magnetization. The time-resolved measurements and modeling will shed light on the fundamental processes leading to atomic reordering and magnetization.

• DFG Programme: Research Grants