The crystal and magnetic structures of the three-leg ladder compound ${\text{Fe}}_3{\text{BO}}_5$ have been investigated by single-crystal x-ray diffraction and neutron powder diffraction. ${\text{Fe}}_3{\text{BO}}_5$ contains two types of three-leg spin ladders. It shows a charge ordering transition at 283 K, an antiferromagnetic transition at 112 K, ferromagnetism below 70 K, and a weak ferromagnetic behavior below 40 K. The x-ray data reveal a smooth charge ordering and an incomplete charge localization down to 110 K. Below the first magnetic transition, the first type of ladders orders as ferromagnetically coupled antiferromagnetic chains, while below 70 K the second type of ladders orders as antiferromagnetically coupled ferromagnetic chains.

• Received 18 August 2008

DOI:https://doi.org/10.1103/PhysRevB.79.144408