Epitaxial growth of the CoFe_2O_4 film on SrTiO_3 and its characterization

摘要

Cobalt ferrite (CoFe_2O_4) thin film is epitaxially grown on (00 1) SrTiO_3 (STO) by laser molecular beam epitaxy (LMBE). The growth modes of CoFe_2O_4 (CFO) film are found to be sensitive to laser repetition, the transitions from layer-by-layer mode to Stranski-Krastanov (SK) mode and then to island mode occur at the laser repetition of 3 and 5 Hz at 700 ℃, respectively. The X-ray diffraction (XRD) results show that the CFO film on (001) SrTiO_3 is compressively strained by the underlying substrate and exhibits high crystallinity with a full-width at half-maximum of 0.86°. Microstructural studies indicate that the as-deposited CFO film is c-oriented island structure with rough surface morphology and the magnetic measurements reveal that the compressive strained CoFe_2O_4 film exhibits an enhanced out-of-plane magnetization (190 emu/cm3) with a large coercivity (3.8 kOe).