Evidence of magnetoelectric coupling on calcium doped bismuth ferrite thin films grown by chemical solution deposition

Abstract

Magnetoelectric coupling was observed at room temperature in calcium modified bismuth ferrite BiFeO3 (BFO) thin films deposited on Pt/TiO2/SiO2/Si (100) substrates by the chemical solution deposition. Undoped and Ca-doped BiFeO3 films were coherently grown at a temperature of 500 °C for 2 h. The highest doped BFO film has a tetragonal structure with P4mm space group, while BFO has a rhombohedral structure with space group R3c, which can be treated as a special triclinic structure. Room temperature magnetic coercive field indicates that the undoped film is magnetically soft with maximum magnetoelectric coefficient in the longitudinal direction was about 12 V/cm. Adding Ca2+ ions to BFO in high concentration decreases the remnant polarization and stabilizes the charged domain walls which interact with oxygen vacancies reducing coercive field.