INVESTIGADORES
CANEIRO Alberto
artículos
Título:
Tunneling barrier in nanoparticle junctions of La2Õ3„Ca,Sr…1Õ3MnO3 : Nonlinear current–voltage characteristics
Autor/es:
D. NIEBIESKIKWIAT; D.M. SANCHEZ; A. CANEIRO; L.E. HUESO
Revista:
JOURNAL OF APPLIED PHYSICS
Editorial:
AMER INST PHYSICS
Referencias:
Lugar: New York; Año: 2003 vol. 83 p. 6305 - 6310
ISSN:
0021-8979
Resumen:
We study the nonlinear current–voltage (I –V) characteristics and analyze the voltage-dependenttunneling conductance in nanoparticles of La2/3A1/3MnO3 (A5Ca, Sr!. The powders were preparedby different wet-chemical routes and low calcination temperatures were used to obtain an averageparticle size D'30 nm. The data are comprehensively explained in terms of the tunneling picture,which allows one to estimate the height of the grain boundary insulating barrier ~w! for each sample.For constant D, our results show that the sample preparation route is mainly responsible for thevalue of w in nanoparticles, while the Coulomb gap in the Coulomb blockade regime is ;3 timeshigher for Sr- than for Ca-doping. We also show that a small fraction of the barriers contribute tothe nonlinear transport, and the current is mainly carried through low-resistive percolated paths. Inaddition, despite the different barrier strengths, the low-field magnetoresistance ~LFMR! is similarfor all samples, implying that w is not the fundamental parameter determining the LFMR.