Detection of spin-resolved electronic states from a buried ferromagnetic layer

The direct observation of spin-resolved electronic states in a ferromagnetic layer that is buried in nonmagnetic material is critical for the development of devices such as hard disk heads that read data from magnetic recording media. However, it is difficult to obtain detailed information on buried ferromagnetic layers by using traditional spin-resolved photoemission spectroscopy, which is the method to measure the spin-resolved surface electronic states of materials.

In order to measure the spin-resolved electronic states in a buried ferromagnetic layer, the research team used a high-brilliant hard X-ray generated by the third generation synchrotron radiation facility, SPring-8, since hard X-ray photoemission spectroscopy is known to be able to measure the electronic states from buried layers. In addition, the researchers invented a new approach for electron spin detection method, which was combined with hard X-ray photoemission spectroscopy, greatly improving the detection efficiency. For example, the team group successfully detected the spin-resolved electronic states in a ferromagnetic layer made of FeNi (iron-nickel) alloy, which was buried under an Au (gold) thin film using this method.

This new technique enables the direct observation of spin-resolved electronic states of ferromagnetic materials near the interface between the ferromagnetic and nonmagnetic layers. This technique will contribute to improvement in the performance of devices containing ferromagnetic materials and to the development of new spintronics materials through a comparison between the performance of spintronics devices and spin-resolved electronics states in ferromagnetic materials in the vicinity of the interface between the ferromagnetic and nonmagnetic layers.

These results have been published in Applied Physics Letters, a publication of the American Institute of Physics.