Exchange bias in GeMn nanocolumns: the role of surface oxidation

Abstract

We report on the exchange biasing of self-assembled ferromagnetic GeMn nanocolumns by GeMn-oxide caps. The x-ray absorption spectroscopy analysis of this surface oxide shows a multiplet fine structure that is typical of the Mn2+ valence state in MnO. A magnetization hysteresis shift |HE|~100 Oe and a coercivity enhancement of about 70 Oe have been obtained upon cooling (300-5 K) in a magnetic field as low as 0.25 T. This exchange bias is attributed to the interface coupling between the ferromagnetic nanocolumns and the antiferromagnetic MnO-like caps. The effect enhancement is achieved by depositing a MnO layer on the GeMn nanocolumns.

7 pages, 5 figures

References in corpus (3)

• Electric field control of exchange bias in multiferroic epitaxial heterostructures
• Spin transfer in an antiferromagnet
• Structure and magnetism of self-organized Ge(1-x)Mn(x) nano-columns

Cited by in corpus (5)

• Resonant Elastic Soft X-Ray Scattering
• Interface-driven phase separation in multifunctional materials: the case of GeMn ferromagnetic semiconductor
• Strain and correlation of self-organized Ge_(1-x)Mn_x nanocolumns embedded in Ge (001)
• Magnetic Mn5Ge3 nanocrystals embedded in crystalline Ge: a magnet/semiconductor hybrid synthesized by ion implantation
• Core-shell nanostructure in a Ge_0.9Mn_0.1 film from structural and magnetic measurements