Fe delta-doped (In,Fe)Sb ferromagnetic semiconductor thin films for magnetic-field sensors with ultrahigh Hall sensitivity.

Highlights • Epitaxial growth of Fe delta-doped (In,Fe)Sb thin films. • Intrinsic ferromagnetism confirmed by MCD spectroscopy measurements. • T C lower than the uniformly-doped (ln,Fe)Sb with the same average Fe concentration. • Much higher Hall sensitivity of the δ-doped samples than those of uniformly-doped. • Very promising for highly sensitive anomalous Hall effect sensors. Abstract We have grown Fe δ-doped (In,Fe)Sb thin films by low-temperature molecular beam epitaxy for magnetic-field sensors with ultrahigh Hall sensitivity. Magnetic circular dichroism spectroscopy measurements indicate intrinsic ferromagnetism in the Fe δ-doped (In,Fe)Sb layers. Although the Fe δ-doped (In,Fe)Sb thin films have lower Curie temperature than the Fe uniformly-doped (ln,Fe)Sb with the same average Fe concentration, their anomalous Hall effect is much stronger. The Hall sensitivity of the Fe δ-doped (In 1−〈 x 〉 ,Fe 〈 x 〉)Sb sample with an average Fe concentration 〈 x 〉 = 17% reaches 1522 Ω/T at room temperature, which is much higher than those of Fe uniformly-doped (In,Fe)Sb, (Ga,Fe)Sb, and commercial InSb Hall sensors. [ABSTRACT FROM AUTHOR]