Time-resolved Nanosecond-Laser Recrystallization of Amorphous FeDy-O Thin Films in the (S)TEM*

Iron-Dysprosium oxide thin film can be an amorphous semiconductor with unusual magneto-optic properties. The properties of amorphous materials are often governed by local structure and recrystallization mechanism is important for the stability of the materials system as well as engineering of properties. To investigate the structure and chemical composition of this material, we employed laser processing inside the (S)TEM with simultaneous High-Resolution Transmission Electron Microscopy (HRTEM) imaging, Electron Diffraction, and Electron Energy Loss Spectroscopy (EELS) measurements. It shows that the structural change in amorphous FeDy-O can be seen as early as with 100 ns single laser pulse at the laser fluency of 1.49E6 J/cm² as indicated by the emergence of sharp diffraction rings from initial broad and diffuse diffraction ring. The pulsed laser-induced changes were studied up to 10,000 pulses where intense Brag’s spots were visible. Our results provide insight on unique way of understanding the local structure evolution and time resolution of the recrystallization process with laser pulses and allow us to conclude back onto the amorphous atomic arrangement of this material system.