Selective Synthesis of Peapodlike Ni/Ni3S2 Nanochains and Nickel Sulfide Hollow Chains and Their Magnetic Properties

✍ Scribed by Wei Zhou; Weimeng Chen; Jianwei Nai; PengGang Yin; Chinping Chen; Lin Guo

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 827 KB
• Volume: 20
• Category: Article
• ISSN: 1616-301X
• DOI: 10.1002/adfm.201001287

✦ Synopsis

Abstract

Peapodlike Ni/Ni~3~S~2~ chains of about 30 nm in outer diameter, with Ni cores of 10–15 nm, can be synthesized by a sacrificial template route. The Ni~3~S~2~ shell exhibits paramagnetic properties with a mass susceptibility of χ ≈ 5 × 10^−5^ emu (gOe)^−1^, while the ferromagnetic Ni cores show a superparamagnetic behavior with a blocking temperature of T~B~ ≈ 130 K. The shape anisotropy of the chainlike structure is determined as 5.0 × 10^4^ J·m^−3^, which is larger than the bulk magnetocrystalline anisotropy by one order of magnitude. The demagnetization factor is determined as Δ__N__ = 0.29. The sample provides an ideal structure for studying the magnetization reversal property by the chain‐of‐sphere model. The observations on the formation of the peapod structure verify a growth mechanism of the nanoscale Kirkendall effect. Based on the preparation of peapod chains, a series of nickel sulfide hollow chains with average diameters of 25, 50, and 100 nm are fabricated. In addition, the phase transition for hollow chains from Ni~3~S~2~ to NiS is studied.