Exploring possible ferromagnetism of the LaAlO3/SrTiO3 interface

The conducting interfaces between the insulators LaAlO${}_{3}$ and SrTiO${}_{3}$ generate a variety of phenomena that are entirely unexpected for insulators. These phenomena include two-dimensional superconductivity and ferromagnetism. A variety of models for mechanisms causing the ferromagnetism has been proposed. By applying a broad set of local and integral measurement techniques to series of samples fabricated to be virtually free of magnetic contaminations, authors' studies conclusively show that the LaAlO${}_{3}$-SrTiO${}_{3}$ interfaces do not intrinsically induce ferromagnetism. The magnetism is caused by defects such as oxygen vacancies generated at the interfaces.