Bulk conduction and nonlinear behaviour in multiferroic YMnO₃

Electrical conductivity of YMnO₃ in O₂, air, and N₂ has been investigated by impedance spectroscopy. Within the investigated temperature range, three types of electrical conductivity were distinguished. Below 300 °C, the conductivity is dominated by p-type conductivity, while between 300 and 500 °C, the conductivity is in the so called saturation region. Above 500 °C, n-type conductivity occurred, probably due to the loss of oxygen. The air-processed YMnO₃ is characterized by the presence of mixed Mn³⁺/Mn⁴⁺ and electrical heterogeneous structure, which are responsible for both, dielectric anomaly observed between 200 and 300 °C and nonlinear behavior under high electric field.