Short communication Resistive hysteresis in BiFeO 3 thin films Jiagang Wu a, *, John Wang b , Dingquan Xiao a , Jianguo Zhu a a Department of Materials Science and Engineering, Sichuan University, Sichuan 610064, PR China b Department of Materials Science and Engineering, National University of Singapore, 117574, Singapore 1. Introduction Resistive switching offers a potential alternative of information storage to the charge-based storages owing to its no scaling limit [1]. Indeed, the resistive switching induced by applied electric field has been recently given to considerable attention for storage applications [1,2]. Several systems have been demonstrated for the resistive switching [3–7]. Considerable stable resistive switching has been observed with certain ferroelectric systems, which have attracted increasing attention as candidates for the resistive information storage [3], although the physical origin of resistive hysteresis is still controversial. BiFeO 3 (BFO) thin film possesses a giant remanent polarization, a room-temperature magnetization, and a high Curie temperature (T c = 1103 K), promising as a candidate material for several technologically demanding applica- tions [8]. Although the switchable ferroelectric diode-like behavior has been reported for the BFO single crystal [9], few studies have been made of the resistive hysteresis in the BFO thin film in the ‘‘metal–ferroelectrics–metal’’ structure. Therefore, it is of consid- erable interest to investigate the feasibility of realizing the resistive behavior for the BFO thin films. In this paper, we report the resistive switching of BFO thin films in capacitor like structure of 300 nm in thickness at room temperature. Based on the investigation into their I–V behavior, the dominant process responsible for the resistive switching is demonstrated. 2. Experimental procedure BFO thin films were deposited by rf sputtering from pre- fabricated BFO ceramic target. The (1 1 1)-oriented BFO thin film was deposited on the SrRuO 3 (SRO)/SrTiO 3 (STO) (1 1 1) substrate at the substrate temperature of 650 8C. The BFO thin film and SRO buffer layer were deposited under a rf power of respective 120 W and 80 W, and the rf deposition was carried out under a base pressure of 3.0  10 6 Torr and a deposition pressure of 10 mTorr with Ar and O 2 at a ratio of 4:1. Circular Au top electrodes of 0.10 mm in diameter were sputtered on the thin film surfaces by using a shadow mask. Their leakage behavior were characterized by using a Keithley meter (Keithley 6430, Cleveland, OH) in the voltage range of 1–12 V (the sweeping direction of the applied bias voltage was V max ! + V max ! V max ) at a delay time of 5 s. Its P–V loops were studied by using the Radiant Precise Workstation (Radiant Technologies, Medina, NY). 3. Results and discussion Fig. 1 plots the I–V curves of the BFO thin film, and several interested phenomena were observed. Firstly, the resistive hysteresis appears to be voltage dependent. That is, an appropriate resistive hysteresis of I–V curve is developed only at the applied bias voltage (V bias ) > 5 V, and no resistive hysteresis was observed at V bias  5 V. Secondly, the diode-like behavior is largely absent in the voltage range investigated. Indeed, a distinctive leakage change is not observed, and the rectification ratio between the high- and low-leakage is kept constant (13) in 6–12 V. The low rectification ratio is attributed to the different work–function effect asymmetric metal (Au)–ferroelectrics (BFO)–metal (SRO) structure [10]. Materials Research Bulletin 46 (2011) 2183–2186 A R T I C L E I N F O Article history: Received 18 January 2011 Received in revised form 12 July 2011 Accepted 20 July 2011 Available online 29 July 2011 Keywords: A. Thin films B. Sputtering D. Electrical properties A B S T R A C T Capacitor-like Au/BiFeO 3 /SrRuO 3 thin film with (1 1 1) orientation was grown on the SrTiO 3 (1 1 1) substrate by radio frequency magnetic sputtering. It shows a resistive switching behavior, where a stable hysteresis in current–voltage curve was well developed by applying an optimum voltage at room temperature, and it reached the saturation at a bias voltage of 8 V. The Child’s law in V max ! 0 direction and the interface-limited Fowler–Nordheim tunneling in 0 ! V max direction, together with the polarization reversal in the BiFeO 3 barrier, are shown to involve in the observed resistive hysteresis. ß 2011 Elsevier Ltd. All rights reserved. * Corresponding author. Tel.: +86 28 85412415; fax: +86 28 85415045. E-mail addresses: wujiagang0208@163.com, msewujg@scu.edu.cn (J. Wu). Contents lists available at ScienceDirect Materials Research Bulletin jo u rn al h om ep age: ww w.els evier.c o m/lo c ate/mat res b u 0025-5408/$ – see front matter ß 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.materresbull.2011.07.030