Nernst effect measurements on LaNiO₃ grown by molecular beam epitaxy

Perovskite LaNiO₃ is a correlated metal, the only member in the ReNiO₃ (Re = Rare earth) series showing metallic behavior down to the lowest temperatures. Recently, LaNiO₃ has received renewed attention due to advancements in growth techniques for producing high quality bulk single crystal samples with very low resistivities, leading also to a re-examination of the magnetic properties of LaNiO₃. In this work, we report on Nernst effect measurements on LaNiO₃ thin films grown by ozone-assisted molecular beam epitaxy. The films have a resistivity of ~ 16 µΩ cm at T = 2 K with a residual resistivity ratio (R(300 K)/R(2 K)) > 8. Hall measurements indicate that the majority charge carriers are hole like, with an increasing Hall slope as temperature decreases. In the Nernst signal, there is a sign change at low temperatures, which is unusual. This phenomenon combined with other transport measurements will be discussed in the context of what is known about the electronic and magnetic properties of this correlated metal.