Chemical order-disorder nanodomains in Fe3Pt bulk alloy

Qiang Li; Yang Ren; Qinghua Zhang; Lin Gu; Qingzhen Huang; Hui Wu; Jing Sun; Yili Cao; Kun Lin; Xianran Xing

doi:10.1093/nsr/nwac053

Chemical order-disorder nanodomains in Fe₃Pt bulk alloy

Natl Sci Rev. 2022 Mar 21;9(12):nwac053. doi: 10.1093/nsr/nwac053. eCollection 2022 Dec.

Authors

Qiang Li¹, Yang Ren², Qinghua Zhang³, Lin Gu³, Qingzhen Huang⁴, Hui Wu⁴, Jing Sun¹, Yili Cao¹, Kun Lin¹, Xianran Xing¹

Affiliations

¹ Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China.
² X-Ray Science Division, Argonne National Laboratory, Argonne, IL 60439, USA.
³ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
⁴ NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102, USA.

Abstract

Chemical ordering is a common phenomenon and highly correlated with the properties of solid materials. By means of the redistribution of atoms and chemical bonds, it invokes an effective lattice adjustment and tailors corresponding physical properties. To date, however, directly probing the 3D interfacial interactions of chemical ordering remains a big challenge. In this work, we deciphered the interlaced distribution of nanosized domains with chemical order/disorder in Fe₃Pt bulk alloy. HAADF-STEM images evidence the existence of such nanodomains. The reverse Monte Carlo method with the X-ray pair distribution function data reveal the 3D distribution of local structures and the tensile effect in the disordered domains at the single-atomic level. The chemical bonding around the domain boundary changes the bonding feature in the disordered side and reduces the local magnetic moment of Fe atoms. This results in a suppressed negative thermal expansion and extended temperature range in Fe₃Pt bulk alloy with nanodomains. Our study demonstrates a local revelation for the chemical order/disorder nanodomains in bulk alloy. The understanding gained from atomic short-range interactions within the domain boundaries provides useful insights with regard to designing new functional compounds.

Keywords: Fe3Pt alloy; chemical order; local structure; nanodomain; pair distribution function.