Room-temperature ferromagnetism and hydrogen shallow donors in rare-earth Eu-doped ZnO nanorods

Abstract

Prominent room-temperature ferromagnetism in rare-earth Eu-doped ZnO nanorods has been investigated by means of magnetization and electron paramagnetic resonance (EPR) measurements. The magnetism of the unhydrogenated Eu-doped ZnO nanorods is explained by a spin-1/2 species, attributed to the Zn vacancies. In the hydrogenated Eu-doped ZnO nanorods, a spin-1 species, attributed to the Zn vacancies coupled to the hydrogen shallow donors, would give rise to a slightly enhanced magnetization. The hydrogen shallow donors, identified by the electron paramagnetic resonance (EPR) measurements, can be taken to be responsible for the changes in the spin states and magnetization of the Eu-doped ZnO nanorods.