Dielectric tunability and magnetoelectric coupling in LuFe_2O_4 epitaxial thin film deposited by pulsed-laser deposition

摘要

C-axis orientated LuFe_2O_4 thin films on (001) sapphire substrates are epitaxially deposited by pulsed-laser deposition. Temperature-dependent resistance characterization reveals the ferrimagnetic transition at 237 K and charge-ordering transition at 340 K in the film. Importantly, the dielectric constant of the film can be significantly changed by both electric and magnetic fields. The dielectric tunability reaches 35% when an electric field of 5 V is applied, while this value reduces to 20% and 15%, respectively, when a magnetic field of 0.83 T is applied perpendicular and parallel to the film normal direction. This suggests a magnetically controlled dielectric tunability and strong magnetoelectric coupling, and is therefore promising for tunable device applications in film form.