title: Giant negative thermal expansion in NaZn13-type La(Fe, Si, Co)13 compounds.
abstract: La(Fe, Si)13-based compounds are well-known magnetocaloric materials, which show a pronounced negative thermal expansion (NTE) around the Curie temperature but have not been considered as NTE materials for industrial applications. The NaZn13-type LaFe13-xSix and LaFe11.5-xCoxSi1.5 compounds were synthesized, and their linear NTE properties were investigated. By optimizing the chemical composition, the sharp volume change in La(Fe, Si)13-based compounds was successfully modified into continuous expansion. By increasing the amount of Co dopant in LaFe11.5-xCoxSi1.5, the NTE shifts toward a higher temperature region, and also the NTE operation-temperature window becomes broader. Typically, the linear NTE coefficient identified in the LaFe10.5Co1.0Si1.5 compound reaches as much as -26.1 × 10(-6) K(-1), with an operation-temperature window of 110 K from 240 to 350 K, which includes room temperature. Such control of the specific composition and the NTE properties of La(Fe, Si)13-based compounds suggests their potential application as NTE materials.
authors.affiliation: Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China.
authors.forename: Rongjin
authors.initials: R
authors.lastname: Huang
authors.forename: Yanying
authors.initials: Y
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Fan
authors.forename: Jie
authors.initials: J
authors.lastname: Tan
authors.forename: Furen
authors.initials: F
authors.lastname: Xiao
authors.forename: Lihe
authors.initials: L
authors.lastname: Qian
authors.forename: Laifeng
authors.initials: L
authors.lastname: Li