Magnetic Structure of Iron Monophosphide

Abstract

Neutron-diffraction measurements have shown that FeP is magnetically ordered below 125 \ifmmode^\circ\else\textdegree\fi{}K. The magnetic structure is a double helix, propagating along the $c$ axis of the Pnma crystal structure with a period of 29.2 \AA{}. The magnetic structure allows two different sites for the iron atoms, with magnetic moments ${\ensuremath{\mu}}_{1}=0.46{\ensuremath{\mu}}_{B}$, ${\ensuremath{\mu}}_{2}=0.37{\ensuremath{\mu}}_{B}$. The form factor for iron is considerably more expanded than the calculated $3d$ free-atom form factor.