Ultraviolet–Visible Magnetic Circular Dichroism Spectroscopy and Its Application of Magnetic Materials 2018
Hua Shu Hsu1*, Huai Sheng Hsu1, Jing Ya Huang1, Ya Huei Huang1
1Department of Applied Physics, National Pingtung University, Pingtung, Taiwan
* Presenter:Hua Shu Hsu, email:hshsu@mail.nptu.edu.tw
Energy dependent magnetic circular dichroism (MCD) and spectra, from which the difference between the absorptions of left and right circularly polarized light at specific energies can be determined, can provide valuable information of the spin polarized density of states. Ultraviolet–visible (2 eV–6 eV) MCD spectroscopy has also been considered as a powerful tool especially for studying the spin-polarized band structures of a semiconductor between its conduction band and the valence band. It is an old technique but has new applications.
This talk will address some examples:
[1] We can observe a room temperature sizable magneto-absorption (MA) effect in Co-coated ZnO nanowires. The MA effect is energy dependent and its value reaches a maximum in the ultraviolet region. By taking a cue from the shape and the peak position of MCD spectra, a two-peaked density of states related to magnetic field-dependent spin splitting has been proposed to describe the MA, which is controlled by the energy and the magnetic field. The MA effect in magnetic material and semiconductor hybrid nanostructures might provide far-reaching opportunities for the development of opto-spintronics application devices.
[2] The electrical manipulation of magneto-optical properties has been achieved in Co/C heterostructures using MCD measurements. It can be associated with the C-Co reversible hybridization variation in turn affects the magnetization behavior by change in orbital occupancy in Co due to charging effect at the interface between Co and C. We expect such results would open new a perspective for carbon based spintronics.
An overview of the basic MCD ideas underlying this research and several applications will also be presented.

Keywords: MCD, magneto-absorption, Carbon, ZnO