Highly c-axis oriented sol-gel (Zn1-xMgx)O films were deposited on Pt/Ti/SiO2/Si substrates. Resistive switching behaviors with stable switching and high resistance ratio were demonstrated for the Pt/(Zn0.9Mg0.1)O/Pt stacks. The effect of the film thickness and the annealing temperature on resistive switching was discussed. Higher substitution of Mg for Zn results in higher resistance of (Zn1-xMgx)O films, which is beneficial for resistive switching to occur at thinner film thickness. The mechanisms dominating the low and the high resistance states are Ohmic conduction and Poole-Frenkel emission, respectively. The resistance ratio varies from 140 to 1000, which is much higher than the value 25 reported recently for sol-gel (Zn0.8Mg0.2)O films. Films annealed at higher annealing temperatures possess higher resistance ratio. (C) 2011 Elsevier B.V. All rights reserved.