Dear Myriam Lachheb , you could try with gold deposition followed by lithography to define your contacts by etching the unwanted gold area. Another option would be to coat your sample with a photoresist, applying a mask with the contacts you want, develop, coat with gold and then remove the resist and the gold over it, leaving just the gold contacts. It could be gold or any other metal available. This technique can be applied even in small substrates.

Hope it helps!

Ok

Dear Manuel Gómez thank you very much for your answer.

From my experience, the contact needed here is covering the whole sample surface (bottom and top). The electric field cannot be applied only in a small region because the poling would be unstable.

Do you think I could pole (apply a large voltage 150-300 V at the Curie temperature 120-130°C, and cool the sample through the phase transition to room temperature under an electric field) my ferroelectric sample while keeping the photoresist material under the gold thin film (top and bottom electrode)? that way, I could protect my sample from getting damaged/dirty during the poling and remove the gold thin film easily (acetone ultrasonic bath ?). Would the poling be effective in this circumstances ?

Thank you very much