title: Nanospheres of a new intermetallic FeSn5 phase: synthesis, magnetic properties and anode performance in Li-ion batteries.
abstract: We synthesized monodisperse nanospheres of an intermetallic FeSn(5) phase via a nanocrystal-conversion protocol using preformed Sn nanospheres as templates. This tetragonal phase in P4/mcc space group, along with the defect structure Fe(0.74)Sn(5) of our nanospheres, has been resolved by synchrotron X-ray diffraction and Rietveld refinement. Importantly, FeSn(5), which is not yet established in the Fe-Sn phase diagram, exhibits a quasi-one dimensional crystal structure along the c-axis, thus leading to interesting anisotropic thermal expansion and magnetic properties. Magnetization measurements indicate that nanospheres are superparamagnetic above the blocking temperature T(B) = 300 K, which is associated with the higher magnetocrystalline anisotropy constant K = 3.33 kJ m(-3). The combination of the magnetization measurements and first-principles density functional theory calculations reveals the canted antiferromagnetic nature with significant spin fluctuation in lattice a-b plane. The low Fe concentration also leads Fe(0.74)Sn(5) to enhanced capacity as an anode in Li ion batteries.
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Xiao-Liang
authors.initials: XL
authors.lastname: Wang
authors.forename: Mikhail
authors.initials: M
authors.lastname: Feygenson
authors.forename: Haiyan
authors.initials: H
authors.lastname: Chen
authors.forename: Chia-Hui
authors.initials: CH
authors.lastname: Lin
authors.forename: Wei
authors.initials: W
authors.lastname: Ku
authors.forename: Jianming
authors.initials: J
authors.lastname: Bai
authors.forename: Meigan C
authors.initials: MC
authors.lastname: Aronson
authors.forename: Trevor A
authors.initials: TA
authors.lastname: Tyson
authors.forename: Wei-Qiang
authors.initials: WQ
authors.lastname: Han