Leakage mechanisms in bismuth ferrite-lead titanate thin films on Pt∕Si substrates

Abstract

( 1 − x ) Bi Fe O 3 – x Pb Ti O 3 (0.5<x<0.3) thin films have been reported to exhibit high remanent polarizations but device integration is hindered by the presence of leakage currents. An insight into the nature of leakage mechanisms in the films is presented. Films with x=0.4 and 0.5 exhibit lower leakage currents as compared to x=0.3 films. At applied fields above 190kVcm−1, in the region of the coercive field of these films, x=0.4 and 0.5 exhibit a Poole–Frenkel mechanism while films with x=0.3 exhibit a combination of space charge limited current and the Schottky effect.

Multiferroicity: the coupling between magnetic and polarization orders

“…While practical applications prefer high quality BiFeO 3 thin films in heteroepitaxial form, a large amount of effort was devoted to thin films of BiFeO 3 [74][75][76][77][78][79][80] where the crystal structure is monoclinic rather than rhombohedral as seen in bulk ceramic samples, due to the strain of substrates. Nowadays, high quality BiFeO 3 epitaxial films with room-temperature polarization as high as 60~80 μC/cm 2 which approaches the theoretical value, are available [74,81].…”

Analysis of Leakage Current Mechanisms in BiFeO3Thin Films

“…2 the PhAT model describes the lnJ against 1/T curves well. As noted above, the presence of a Poole-Frenkel conduction mechanism has been reported for (1−x)BiFeO 3 -xPbTiO 3 (0.5 < x < 0.3) thin films with x = 0.4 and x = 0.5 Khan et al [7]. The fit of that data to the PhAT model is displayed in Fig.…”

“…Despite the fact that electronic conduction properties of those structures have been studied in some works [3][4][5][6][7], the current nonlinear behavior and its temperature variation are not fully understood yet. For instance, Qi et al [3] asserted that the main conduction mechanism for pure and Ni 2+ doped BFO was a space charge limited current (SCLC), while Pabst et al [5] affirmed that the Poole-Frenkel (PF) emission was the predominant mechanism in the high quality epitaxial BFO film formed by pulsed laser deposition (PLD) symmetric SrRuO 3 /BFO/SrRuO 3 capacitors and no clear dominant current mechanism can be attributed for the asymmetric Pt/BFO/SrRuO 3 structures.…”

“…3in[7] (symbols) fitted to the theoretical ln W 1 against 1/T dependences (solid lines), computed for parameters: a = 3.2, m * = 0.2 m e , ε T = 1.05 eV, ω = 50 meV.…”

Effects of ultraviolet irradiation and soak time on the leakage current of Bi3.25La0.75Ti3O12 thin films

“…It is reported that [9,13,14], in low voltage (or electric field) region, the leakage current behaviour introduced by thermal generated carriers would follow the Ohmic conduction mechanism. In detail, in low voltage region, the leakage current mainly comes from the thermal excitation of trapped electrons in films from one trap site to another.…”