SPring-8, the large synchrotron radiation facility

Release Date

02 Apr, 2014

April 2, 2014
National Institute for Materials Science (NIMS)
Institute for Materials Research (IMR), Tohoku University
Research Institute of Electrical Communication (RIEC), Tohoku University

Abstract

1. The joint research group led by Shigenori Ueda, NIMS (Sukekatsu Ushioda, executive president) senior researcher of Synchrotron X-ray Group, Quantum Beam Unit, Masaki Mizuguchi, associate professor at IMR, Tohoku University, and Masafumi Shirai, professor at RIEC, Tohoku University, successfully detected spin-resolved electronic states from a buried ferromagnetic layer, which had been difficult to detect using conventional spin-resolved photoemission spectroscopy.
2. 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.
3. In order to measure the spin-resolved electronic states in a buried ferromagnetic layer, the research group 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 research group 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 research 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.
4. 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.
5. These results has been published in Applied Physics Letters, the American Institute of Physics.