Great enhancement in remnant polarisation of SrBi4Ti4O15 thin films by A-site doping of Fe3+ ions

SrBi4-xFexTi4O15 (SBFT-x) thin films (x = 0.00, 0.05, 0.08, 0.15) have been synthesized on Pt/Ti/SiO2/Si (100) substrates by sol-gel method. This paper finds that Fe-doping does not change the crystal structure of SrBi4Ti4O15 (SBTi). The coercive filed (E-c) and remnant polarisation (P-r) increase at first, then decrease with the increase of Fe doping content. At a maximum applied field of 229 kV/cm, the 2P(r) reaches a maximum value of 91.1 mu C/cm(2) at x - 0.05 and the corresponding E-c is 72 kV/cm. The 2P(r) increases by about 260% and the E-c decreases by about 6%, respectively. Obviously, the ferroelectric property of SrBi4Ti4O15 is greatly enhanced by Fe doping. The fatigue-endurance characteristic of the SBFT-0.05 is not improved. After 1.1 x 10(9) read/write cycles at a frequency of 50 kHz, the nonvolatile polarisations (P-nv = P* - P-boolean AND) decreased about 48% of its initial value.