Title

Application of De-silylation Strategies to The Preparation of Transition Metal Pnictide Nanocrystals: The Case of FeP

Document Type

Article

Publication Date

9-24-2003

Publication Title

Chemistry of Materials

Abstract

Phase-pure FeP nanoparticles have been synthesized by the reaction of iron(III) acetylacetonate with tris(trimethylsilyl)phosphine at temperatures of 240−320 °C using trioctylphosphine oxide as a solvent and dodecylamine (DA), myristic acid (MA), or hexylphosphonic acid (HPA) as additional capping groups (ligands). The DA-capped particles prepared at 260 °C have an average diameter of 4.65 ± 0.74 nm with FeP being the only observed crystalline phase. Elemental analyses indicate a high percentage yield of FeP (85%) and are consistent with 12% TOPO incorporation in the product. The addition of MA has results similar to those of the addition of DA, whereas addition of HPA seems to inhibit crystallite growth, resulting in very small (ca. 1 nm) or amorphous particles that are difficult to isolate. Magnetic susceptibility data on DA-capped FeP suggest that the moments within each particle are coupled antiferromagnetically, at least over a short range; however, there is no evidence of a Néel transition, in contrast to bulk FeP. It is likely that the FeP particles produced by this route are too small (ca. 5 nm) relative to the magnetic cell (2.9 nm) for the onset of long-range helical antiferromagnetic order, even at low temperatures (5 K) and fields (0.010 T).

Comments

This work is supported by an NSF-CAREER award (DMR-0094273) and the Institute for Manufacturing Research at Wayne State University. The microscopy was performed at the University of Michigan EMAL on the JEOL 2010F, which was pur-chased under NSF grant DMR-9871177.

DOI

10.1021/cm034443o

Volume

15

Issue

21