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We report the resistive switching (RS) characteristics of Al/TiO2/Au memristive cells fabricated in a crossbar array. The measured R–V curves suggest that RS takes place essentially at the Au/TiO2 interface. We propose a model based on the electric field enhanced migration of oxygen vacancies at that interface which reproduces the main features of the experimental data, namely the remnant resistance states and the degradation process. Obtained vacancy profiles at the active region of the junction give insight for the design of improved devices. Fil: Ghenzi, Néstor. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche); Argentina Fil: Sánchez, María José. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Levy, Pablo Eduardo. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

We study electroforming on the resistive switching (RS) behavior of silver-manganite interfaces. Using the technique of hysteresis switching loops we define an electroforming procedure that enables us to study its influence on the RS behavior in a systematic manner. We show that two similar electroforming procedures may lead to either RS or no RS at all. We explain the observed behavior by associating the forming procedure and the memory switching operation to major and minor hysteresis loops, respectively. With the obtained insight we propose a simple and nearly optimal electroforming procedure.

We present experimental evidence on the physical origin of a magnetic dead layer (MDL) in manganite nanoparticles. The studied nanoparticles constitute the wall of La0.67Sr0.33MnO3 and La0.67Ca0.33MnO3 manganite nanotubes. Magnetic properties analysis and high resolution transmission electron microscopy show a shell of approximately 2 nm thickness with different properties from the core. In this shell the atoms are in a noncrystalline array that perfectly explains the 50% reduction of the magnetization compared to the bulk. Moreover, we present experimental evidence that the internal magnetic structure of the MDL is constituted by small ferromagnetic clusters in a frustrated configuration.

We investigate the electric field induced resistive switching effect and magnetic field induced fraction enlargement on a polycrystalline sample of a colossal magnetoresistive compound displaying intrinsic phase coexistence. Our data show that the electric effect (presumably related to the presence of inhomogeinities) is present in a broad temperature range(300 to 20 K), being observable even in a mostly homogeneous ferromagnetic state. In the temperature range in which low magnetic field determines the phase coexistence fraction, both effects, though related to different mechanisms, are found to determine multilevel nonvolatile memory capabilities simultaneously., Submited to APL

A new etching method for single-crystal Al 2 O 3 is proposed using Ar + implantation and H 3 PO 4 chemical etching. Photolitographically defined patterns are transferred into sharp structures on the wafer surface by selectively removing the damaged material. A double implantation of Ar + at 50 keV followed by 180 keV was performed on all samples, using a dose of 2 x 10 15 ions/cm 2 for the low-energy implant. Doses of 2 x 10 15 , 2 x 10 16 , and 4 x 10 16 ions/cm 2 were used for the 180 keV implant. Scanning electron microscopy and atomic force microscopy were used to characterize the pattern obtained, while transmission electron microscopy and Rutherford backscattering channeling analysis were employed to study the implanted layer. Under the conditions investigated, both the etchable range (90 to 160 nm) and the etching rate (1 to 7 nm/min) were found to be strongly correlated with the implanted dose. Sharp and uniform interfaces between etched and unetched regions were obtained, forming steps with an average slope of 30 to 45°. The proposed method offers high selectivity, lack of contamination of the substrate, and compatibility with standard processing.