126 research outputs found
Metal-insulator transition and electrically-driven memristive characteristics of SmNiO3 thin films
The correlated oxide SmNiO3 (SNO) exhibits an insulator to metal transition
(MIT) at 130 {\deg}C in bulk form. We report on synthesis and electron
transport in SNO films deposited on LaAlO3 (LAO) and Si single crystals. X-ray
diffraction studies show that compressively strained single-phase SNO grows
epitaxially on LAO while on Si, mixed oxide phases are observed. MIT is
observed in resistance-temperature measurements in films grown on both
substrates, with charge transport in-plane for LAO/SNO films and out-of-plane
for Si/SNO films. Electrically-driven memristive behavior is realized in
LAO/SNO films, suggesting that SNO may be relevant for neuromorphic devices
Conductivity noise study of the insulator-metal transition and phase co-existence in epitaxial samarium nickelate thin films
Interaction between the lattice and the orbital degrees of freedom not only
makes rare-earth nickelates unusually "bad metal", but also introduces a
temperature driven insulator-metal phase transition. Here we investigate this
insulator-metal phase transition in thin films of using the
slow time dependent fluctuations (noise) in resistivity. The normalized
magnitude of noise is found to be extremely large, being nearly eight orders of
magnitude higher than thin films of common disordered metallic systems, and
indicates electrical conduction via classical percolation in a spatially
inhomogeneous medium. The higher order statistics of the fluctuations indicate
a strong non-Gaussian component of noise close to the transition, attributing
the inhomogeneity to co-existence of the metallic and insulating phases. Our
experiment offers a new insight on the impact of lattice-orbital coupling on
the microscopic mechanism of electron transport in the rare-earth nickelates.Comment: 5 pages, 4 figure
- …