Evidence for the onset of Fröhlich-mode conductivity in K0.30MoO

The current-voltage measurements under flat-top pulsed magnetic fields for non-ohmic transport study

Investigation of the non-ohmic transport behaviors under high magnetic fields can provide a new way to explore novel field-induced phenomena. We present the current-voltage measurements under high magnetic fields based on the flat-top pulsed magnetic field system. Two different measurement strategies were compared, given that the excitation current swept continuously or increased by a series of pulses. For the short duration of the flat-top pulsed field, the continuous current method was adopted and well optimized to reduce the Joule heating and achieve the quasi-static measurements. Finally, the non-ohmic behaviors of a quasi-one-dimensional charge density wave Li_0.9Mo₆O₁₇ were successfully studied under the magnetic field up to 30 T at 4.2 K, which was the first current-voltage measurements carried out in pulsed magnetic fields.

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.