Resistance random access memory (RRAM) consisting of stacked Al/TiO(x)/Al structure is demonstrated on a flexible and transparent substrate. To improve cell to cell uniformity, TiO(x) formed by atomic layer deposition is used for resistive switching material. The simple cross-bar structure of the RRAM and good ductility of aluminum electrode results in excellent flexibility and mechanical endurance. Particularly, bipolar and unipolar resistive switching (BRS, URS) behavior appeared simultaneously were investigated. Depending on the current compliance, BRS or URS could be selectively observed. Furthermore, the permanent transition from BRS to URS was observed with a specific current compliance. To understand this transition behavior, the gamma-ray irradiation effect into resistive switching is primarily investigated. (C) 2009 Elsevier Ltd. All rights reserved.