title: Broad Negative Thermal Expansion Operation-Temperature Window Achieved by Adjusting Fe-Fe Magnetic Exchange Coupling in La(Fe,Si)13 Compounds.
abstract: Cubic La(Fe,Si)13-based compounds have been recently developed as promising negative thermal expansion(NTE) materials, but the narrow NTE operation-temperature window(∼110 K) restricts their actual applications. In this work, we demonstrate that the NTE operation-temperature window of LaFe(13-x)Si(x) can be significantly broadened by adjusting Fe-Fe magnetic exchange coupling as x ranges from 2.8 to 3.1. In particular, the NTE operation-temperature window of LaFe10.1Si2.9 is extended to 220 K. More attractively, the coefficients of thermal expansion of LaFe10.0Si3.0 and LaFe9.9Si3.1 are homogeneous in the NTE operation-temperature range of about 200 K, which is much valuable for the stability of fabricating devices. The further experimental characterizations combined with first-principles studies reveal that the tetragonal phase is gradually introduced into the cubic phase as the Si content increases, hence modifies the Fe-Fe interatomic distance. The reduction of the overall Fe-Fe magnetic exchange interactions contributes to the broadness of NTE operation-temperature window for LaFe(13-x)Si(x).
authors.affiliation: †State Key Laboratory of Technologies in Space Cryogenic Propellants, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. China.|§University of Chinese Academy of Sciences, Beijing 100049, P.R. China.
authors.forename: Shaopeng
authors.initials: S
authors.lastname: Li
authors.affiliation: †State Key Laboratory of Technologies in Space Cryogenic Propellants, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. China.
authors.forename: Rongjin
authors.initials: R
authors.lastname: Huang
authors.affiliation: †State Key Laboratory of Technologies in Space Cryogenic Propellants, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. China.|§University of Chinese Academy of Sciences, Beijing 100049, P.R. China.
authors.forename: Yuqiang
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: †State Key Laboratory of Technologies in Space Cryogenic Propellants, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. China.|§University of Chinese Academy of Sciences, Beijing 100049, P.R. China.
authors.forename: Wen
authors.initials: W
authors.lastname: Li
authors.affiliation: †State Key Laboratory of Technologies in Space Cryogenic Propellants, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: †State Key Laboratory of Technologies in Space Cryogenic Propellants, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. China.
authors.forename: Chuanjun
authors.initials: C
authors.lastname: Huang
authors.affiliation: §University of Chinese Academy of Sciences, Beijing 100049, P.R. China.
authors.forename: Pifu
authors.initials: P
authors.lastname: Gong
authors.forename: Zheshuai
authors.initials: Z
authors.lastname: Lin
authors.affiliation: †State Key Laboratory of Technologies in Space Cryogenic Propellants, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. China.
authors.forename: Laifeng
authors.initials: L
authors.lastname: Li