Room temperature threshold switching behaviors of Bi_0.9Nd_0.1Fe_1−xCo_xO₃ nanoparticles

Abstract

Many investigations have reported threshold switching (TS) effects in amorphous semiconductors, but it is rarely observed in BiFeO 3 nanoparticles. Here, the effects of cobalt doping on the electrical conductivity of Bi 0.9 Nd 0.1 Fe 1Àx Co x O 3 (x = 0, 0.01, 0.03, 0.05) nanoparticles were investigated. Leakage current density (J) versus applied voltage (V) curves were measured and it was found that the leakage current increases with increases of the cobalt dopant concentration. With the increase of the maximal applied voltage, the samples with cobalt doping exhibit nearly symmetric TS behaviors at room temperature. With the increase of cobalt dopant concentration, the optical band gap is decreased, and the smallest optical band gap value (B2.01 eV) is observed for the 3% Co doped BiFeO 3 sample. X-ray photoelectron spectroscopy of the samples shows that the cobalt dopant induces an enhancement of the oxygen vacancy concentration. Possible mechanisms for the threshold switching effects are discussed on the basis of a conductive filament model. The mobile charge carriers align to form conducting filaments when the threshold voltage (V TH ) is achieved, corresponding to the transition from a high-resistance state to a low-resistance state, and the rupture of the conductive path takes place when the applied voltage is decreased. The leakage current decreases dramatically and eventually returns to the initial high-resistance state.

Abnormal variation of band gap in Zn doped Bi0.9La0.1FeO3 nanoparticles: Role of Fe-O-Fe bond angle and Fe-O bond anisotropy

“…These defects can reduce the band gap since the densities of oxygen vacancy donor and hole acceptor are increased in acceptor-cation doped BFO. 14 In our case, however, the band gap is increased with the substitution of divalent Zn, which seems against the general acceptor-cation doping. Moreover, the samples' particle size observed by SEM (supplementary material (Fig.…”

“…Cation substitutions for both A and B sites in BFO have been shown to modulate the density of defects, [12][13][14] where the effects of doping on the optical and electrical properties can be utilized. Nonmagnetic ion Zn 2þ has a stable ionic charge.…”

Substitution driven structural and magnetic properties and evidence of spin phonon coupling in Sr-doped BiFeO3 nanoparticles

“…9). 49 The position of the valence band maxima (E VBM ) has been determined from the extrapolation of two linear ts of leading edge and base line. It can be seen that the position of E VBM is slightly shied away from the Fermi level with increasing Sr ion content.…”

Study results of the on-board weight control system as exemplified by feed mixture preparation using a trailed feed mixer-and-distributor

“…The research process of the weighing system included sequential supply of materials with remote monitoring of strain-gauge elements using wireless communications and software with neural network algorithms of process monitoring [9,10,12]. To ensure a reliable evaluation, the metered materials were evaluated by groups of components (concentrated and bulk ones) [13]. Taking into account the fact that the use of robotic platforms for the feed mixture distribution is gaining popularity every year [14], the dynamic monitoring of feed mixture distribution also increases the relevance of studies of the effectiveness of weight control systems (metering) [15,16].…”