Subnanosecond phase transition dynamics in laser-shocked iron

H Hwang; E Galtier; H Cynn; I Eom; S H Chun; Y Bang; G C Hwang; J Choi; T Kim; M Kong; S Kwon; K Kang; H J Lee; C Park; J I Lee; Yongmoon Lee; W Yang; S-H Shim; T Vogt; Sangsoo Kim; J Park; Sunam Kim; D Nam; J H Lee; H Hyun; M Kim; T-Y Koo; C-C Kao; T Sekine; Yongjae Lee

doi:10.1126/sciadv.aaz5132

Subnanosecond phase transition dynamics in laser-shocked iron

Sci Adv. 2020 Jun 5;6(23):eaaz5132. doi: 10.1126/sciadv.aaz5132. eCollection 2020 Jun.

Authors

H Hwang¹, E Galtier², H Cynn³, I Eom⁴, S H Chun⁴, Y Bang¹, G C Hwang¹, J Choi¹, T Kim¹, M Kong¹, S Kwon¹, K Kang¹, H J Lee², C Park⁵, J I Lee⁵, Yongmoon Lee⁶, W Yang⁶, S-H Shim⁷, T Vogt⁸, Sangsoo Kim⁴, J Park⁴, Sunam Kim⁴, D Nam⁴, J H Lee⁴, H Hyun⁴, M Kim⁴, T-Y Koo⁴, C-C Kao², T Sekine^{6

9}, Yongjae Lee^{1

6}

Affiliations

¹ Department of Earth System Sciences, Yonsei University, Seoul 03722, Republic of Korea.
² Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
³ High Pressure Physics Group, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
⁴ Pohang Accelerator Laboratory, Pohang, Gyeongbuk 37673, Republic of Korea.
⁵ Korea Polar Research Institute, Incheon 21990, Republic of Korea.
⁶ Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China.
⁷ School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, USA.
⁸ NanoCenter and Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA.
⁹ Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan.

Abstract

Iron is one of the most studied chemical elements due to its sociotechnological and planetary importance; hence, understanding its structural transition dynamics is of vital interest. By combining a short pulse optical laser and an ultrashort free electron laser pulse, we have observed the subnanosecond structural dynamics of iron from high-quality x-ray diffraction data measured at 50-ps intervals up to 2500 ps. We unequivocally identify a three-wave structure during the initial compression and a two-wave structure during the decaying shock, involving all of the known structural types of iron (α-, γ-, and ε-phase). In the final stage, negative lattice pressures are generated by the propagation of rarefaction waves, leading to the formation of expanded phases and the recovery of γ-phase. Our observations demonstrate the unique capability of measuring the atomistic evolution during the entire lattice compression and release processes at unprecedented time and strain rate.

Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).