Leakage mechanisms of self-assembled (BiFeO3)0.5:(Sm2O3)0.5 nanocomposite films

Nanocomposite (BiFeO3)0.5:(Sm2O3)0.5 films were deposited on (001) oriented Nb-doped SrTiO3 substrates by pulsed laser deposition. The leakage current density versus electric field characteristics were investigated and compared with those of as-deposited and annealed pure BiFeO3 (BFO) thin films. The dominant leakage mechanisms of nanocomposite films were space-charge-limited current and Poole–Frenkle emission for positive and negative biases, respectively. The leakage current density of nanocomposite films was reduced three orders of magnitude in comparison with the as-deposited pure BFO films. The less oxygen vacancies in the BFO phase in the nanocomposite is believed to contribute to the leakage reduction.