System of laser pump and synchrotron radiation probe microdiffraction to investigate optical recording process

Nobuhiro Yasuda; Yoshimitsu Fukuyama; Shigeru Kimura; Kiminori Ito; Yoshihito Tanaka; Hitoshi Osawa; Toshiyuki Matsunaga; Rie Kojima; Kazuya Hisada; Akio Tsuchino; Masahiro Birukawa; Noboru Yamada; Koji Sekiguchi; Kazuhiko Fujiie; Osamu Kawakubo; Masaki Takata

doi:10.1063/1.4807858

System of laser pump and synchrotron radiation probe microdiffraction to investigate optical recording process

Rev Sci Instrum. 2013 Jun;84(6):063902. doi: 10.1063/1.4807858.

Authors

Nobuhiro Yasuda¹, Yoshimitsu Fukuyama, Shigeru Kimura, Kiminori Ito, Yoshihito Tanaka, Hitoshi Osawa, Toshiyuki Matsunaga, Rie Kojima, Kazuya Hisada, Akio Tsuchino, Masahiro Birukawa, Noboru Yamada, Koji Sekiguchi, Kazuhiko Fujiie, Osamu Kawakubo, Masaki Takata

Affiliation

¹ Research and Utilization Division, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-gun, Hyogo 679-5198, Japan.

PMID: 23822352
DOI: 10.1063/1.4807858

Abstract

We have developed a system of laser-pump and synchrotron radiation probe microdiffraction to investigate the phase-change process on a nanosecond time scale of Ge2Sb2Te5 film embedded in multi-layer structures, which corresponds to real optical recording media. The measurements were achieved by combining (i) the pump-laser system with a pulse width of 300 ps, (ii) a highly brilliant focused microbeam with wide peak-energy width (ΔE∕E ~ 2%) made by focusing helical undulator radiation without monochromatization, and (iii) a precise sample rotation stage to make repetitive measurements. We successfully detected a very weak time-resolved diffraction signal by using this system from 100-nm-thick Ge2Sb2Te5 phase-change layers. This enabled us to find the dependence of the crystal-amorphous phase change process of the Ge2Sb2Te5 layers on laser power.