Rare Earth-Doped BiFeO3 Thin Films: Relationship between Structural and Magnetic Properties

الملخص EN

Rare Earth- (RE-) doped BiFeO3 (BFO) thin films were grown on LaAlO3 substrates by using pulsed laser deposition technique.

All of BFO films doped with 10% of RE show a single phase of rhombohedral structure.

The saturated magnetization in the Ho- and Sm-doped films is much larger than those reported in literature and was observed at a quite low field as of 0.2 T.

As for Pr- and Nd-doped BFO films, Fe2+ amount is not dominant; thus, ferromagnetism is not favored.

As the RE concentration goes up to 20%, all compounds have drastically gone through a structural transition.

The RE-doped BFO films have changed from rhombohedral to either pure orthorhombic phase (for Ho, Sm), or a mixed phase of orthorhombic and tetragonal (for Pr, Nd), or pure tetragonal (for Eu).

We observed magnetic properties of RE-doped BFO films have significantly changed.

While 20% Ho/Sm-doped BFO films have ferromagnetism degraded in comparison with the 10% doping case, the 20% Pr/Nd-doped BFO thin films, whose structure is a mixed phase, have magnetic ordering improved due to the fact that the Fe2+ amount has become greater.

It seems that one can control the magnetic properties of BFO films by using appropriate RE dopants and concentrations.