Ferromagnetic behaviour from anionic complexes of carbon and boron

Abstract

Anionic element reagent complexes (AERCs) are a new chemical construct that has already shown remarkable functionality for the synthesis of challenging ferromagnetic nanoparticles (e.g. the low temperature phase of MnBi nanoparticles). The fundamental compositional characteristic of an AERC is the complexation of an element by lithium borohydride (LiBH4). Complexation by LiBH4 results in electron density being transferred from the Li ions to the complexed element. Normally, this association is brief because a reducible cationic-form of the complexed element is used, and a rapid reduction occurs (ie . Fe2+ is quickly reduced to Fe0). In the scenarios of AERCs described here, the complexed element is already zero valent, so a stable complex (at ambient temperature) is formed; creating a situation where the complexed element is the recipient of transferred electron density. Nonmetallic carbon and boron examples of AERCs (referred to as CAERC and B-AERC, respectively) have been synthesized and characterized. We report the mechanochemical combination of parent diamagnetic species (LiBH4 and either carbon or boron) that forms novel, single-phased nonmetallic compounds that present ferromagnetic qualities such as temperature dependent magnetizations, susceptibilities and coercivities (e.g. C-AERC: 160 Oe at 10 K to 20 Oe at 400 K).