Impedance study of reproducible switching memory effect

The reproducible switching and memory effect in thin film colossal magnetoresistive (CMR) materials has been further studied. A resistive memory device was made in a sandwich structure comprised of Au or Pt top electrode on Pr/sub 0.17/Ca/sub 0.3/MnO/sub 3/ (PCMO) on Pt/LaAIO/sub 3/(100) (LAO), on Pt/TiN/SiO/sub 2//Si, and on YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// (YBCO) on LaAIO3 (100) substrates. In these samples, polycrystalline PCMO films were deposited on polycrystalline Pt films, and (101) ordered PCMO films were epitaxially grown on c-oriented YBCO crystalline films. Both PCMO and YBCO films were deposited by pulse laser deposition (PLD). The top Au electrode was made by dc-sputtering, and in the case of Pt top and bottom electrodes they were deposited by e-beam evaporation. We have characterized the temperature dependence of the device resistance change R(T) upon electric pulse switching. We have also measured the impedance spectroscopy Z(T,/spl Omega/) of the device in the temperature range of 77K to 300K and the frequency range from 10 to I06 Hz for both the low- resistance and high-resistance states of the resistive memory device. The influence of intrinsic film defects on switching and fatigue properties of the non-volatile resistive memory device, and the switching mechanism itself are discussed.