Tuning oxygen vacancy in LiNbO3 single crystals for prominent memristive and dielectric behaviors
Understanding and manipulating the behavior of oxygen vacancy in oxide materials are of vital importance for rejuvenating materials with novel functionalities. We herein report a exciting phenomenon of oxygen vacancies changing from an isolated state to a clustered state in LiNbO 3 single crystals. The clustering of the oxygen vacancies induces a relaxor-like dielectric anomaly and a first-order phase transition. The relaxor-like dielectric anomaly was argued to be a pseudo-relaxor behavior resulting from the combined contributions of a dipolar relaxation and a Maxwell-Wagner relaxation. The first-order phase transition was ascribed to be an electric-ferroelectric phase transition. Interestingly, a well-defined melting point of the oxygen-vacancy clusters was observed. At temperatures near the point, a small dc field can lead to resistance switching from a high resistance state to a low resistance state, yielding a prominent memristive effect with the OFF/ON ratio of 10 2 . Our results underscore that controlling the oxygen vacancy state is a promising strategy to tailor the properties of oxides for novel device applications.