Magnetic Structures of Metallic Multilayers by Resonant X-ray Magnetic Scattering of Circularly Polarized Synchroton X-rays

点击翻译按钮获取中文摘要

1. Magnetic structures of Gd layers in Fe/Gd metallic multilayers were determined by resonant x-ray magnetic diffraction (RXMD) at the Gd L3 absorption edge. The determined magnetic structures above the compensation temperature (ca. 120 K) are consistent with those derived from a simple theoretical method. The measured M-H curves are reproduced from the determined magnetic structures. The magnetic structures below the compensation temperature cannot be derived from the simple theoretical method, indicating the significant effect of the magnetic anisotropy of the Gd layers on the magnetic structures.2. Magnetic structures of Dy layers in Fe/Dy metallic multilayers were determined by RXMD at the Dy L3 absorption edge. The magnetic structures of the Dy layers between 50 and 300 K are similar to those of the Gd layers in the twisted state of the Fe/Gd metallic multilayers. The origin of the Dy magnetic structures, however, is thought to be different from the Gd case. It is thought to be sc … More rew-type magnetic interaction that the bulk Dy metal inherently has.3. The x-ray magnetic circular dichroism (XMCD) spectra of the Gd/Cu metallic multilayers at the Gd L3 and Cu K absorption edges were measured from low temperature up to the Curie temperature of the Gd layer in order to investigate the basic behavior of the magnetic polarization induced in the nonmagnetic layers in constant with the ferromagnetic layers. Both the (5d) magnetic polarization of the Gd layers and the (4p) polarization of the Cu layers, which are relevant to the XMCD spectra, are proportional to the bulk magnetization (mainly Gd 4f). However, the proportional constant for Cu depends on the Cu layer thickness. This indicates that even if the Gd layer magnetization is the same, the total magnetic moment induced in the Cu layer is different when the Cu layer thickness changes.4. The magnetic field dependence of the Co and Cu XMCD spectra was measured for two Co/Cu samples; one (AF sample) showed the giant magnetoresistance (GMR) effect and the other (F sample) did not. The total magnetic polarization of the Cu layer in the F sample is larger than that in the AF sample if we compare them under the same Co XMCD intensities. A tendency is suggested that the AF sample suppresses the ferromagnetic polarization of the Cu layer.5. In order to measure a distribution of a very small magnetic polarization induced in the nonmagnetic Cu layer by RXMD, we are developing a new system using a high counting rate detector. We successfully observed magnetic Bragg peaks of the magnitude of (I(+)-I(-))/(I(+)+I(-)~ 0.001. Less