Non-linear conduction due to depinning of charge order domains in Fe₃O₂BO₃

The oxyborate Fe₃O₂BO₃ presents a charge density wave (CDW) transition close to room temperature. As we show here, this is associated with a well defined anomaly in the specific heat. Below this transition, when applying in a single crystal of Fe₃O₂BO₃ a DC voltage above a temperature dependent threshold, a high current is liberated in this material. We study the conduction in single crystals of Fe₃O₂BO₃ with voltage applied parallel and perpendicular to the crystallographic c axis direction. The observed currents are attributed to the depinning of charge ordered domains above a threshold voltage V_T2 that gives rise to a collective conduction due to coherent domains. Compliance limited DC data shows that above a lower threshold voltage depinning is smooth and follows a power law scaling. Similar depinning with power law scaling is also revealed in the AC conductivity. (paper)