JSAP is a “conduit” for the transfer of fundamental concepts to the industry for development and technological applications. As shown in Fig. To this end, the JSAP holds annual conferences; publishes scientific journals; actively sponsors events, symposia, and festivals related to science education; and compiles information related to state-of-the-art technology for the public. The red arrow denotes the 2 p to 6 s transition 46 , which indicates electron doping at 6 s. First-principles electronic structure calculations were carried out using the projector augmented-wave method, implemented in the Vienna ab initio simulation package We also find that a voltage induction of the magnetic dipole moment, originating from spin-flip excitation between the exchange-split majority and minority spin bands, dominates the voltage-induced MAE change.
Then, conventional sum-rule analysis can characterize the magnetic moments 47 , 48 , Voltage dependence of the magnetic moments Figure 3 shows the voltage dependence of the magnetic moments and the hole number of the Pt. The coercive field was large at negative voltages, corresponding to the enhanced perpendicular magnetic anisotropy. Express 7 , The microscopic origin of the strong perpendicular magnetic anisotropy of L 1 0 -ordered FePt, however, has not been fully understood yet despite its importance and extensive studies. The importance of the spin-flip term for FePt arises from the large spin-orbit interaction and the small spin splitting of the Pt 5 d electrons.
Published online Jun Such electric quadrupole induction couples with the induction of the magnetic dipole moment and changes the MAE, which will be reviewed later. Fe L 23 -edge XMCD studies have shown the existence of large anisotropy of the orbital magnetic moment, that is, the orbital magnetic moment is larger for magnetic fields perpendicular to the plane, which is enhanced with increasing S. Figure 1c shows a high-angle annular dark-field scanning transmission electron microscopy image of the sample see Method 2, Supplementary Note 2 and Supplementary Fig.
We thinn one potentially unique situation in a metal—dielectric interface in which the electric field is atomically inhomogeneous because of the strong electrostatic screening effect in metals.
Then, we qualitatively discuss the origin for the MAE in FePt MgO system, treating the second-order perturbation of the spin—orbit interaction. The present result demonstrates that theoretical treatment including spin-flip processes is necessary when designing magnetic materials with large MAE utilizing heavy elements.
Adsorbate-substrate and adsorbate-adsorbate interactions of Na and K adlayers on Al As the spin-conserved terms in do not possess orbital angular momenta, they are independent of magnetization direction. In contrast to the magnetic dipole moment, the spin magnetic moment is insensitive to the magnetization direction 4551 We have employed the following equation as the perpendicular MAE From equation 4the magnetic dipole moments projected in the directions perpendicular and in-plane to the film are given by andrespectively.
Bruno has derived a simplified relation between the MAE and the anisotropy of the orbital magnetic moment by ignoring the second term of Eq. In a manner similar to the one exhibited by the perpendicular MAE in Fig.
X-ray circular dichroism and local magnetic fields. Table 1 Experimentally determined magnetic moments and hole numbers of FePt.
Voltage controlled interfacial magnetism through platinum orbits. Because an electric field applied to the metal—dielectric is inhomogeneous because of the strong electrostatic screening effect in metals, such an electric field, including higher-order lrbital components, can couple with the electric quadrupole correlating to the magnetic dipole moment in an electron shell in a metal layer as shown in Fig.
In this configuration, positive external voltages induce electron accumulations at the Pt—MgO interface. In our chemically ordered FePt alloy, one monatomic layer of coverage by the Pt was the best condition for VCMA; however, less than one monatomic layer of coverage may exhibit their VCMA maximum in the case of chemically disordered alloys, which should show different orbital and dipole contributions Voltage dependence of the magnetic moments and hole numbers of Pt.
The data that support these findings are available from the corresponding author S. Electric field-induced modification of magnetism in thin-film ferromagnets. Support Center Support Center.
Although the Bruno relationship [Eq. Electrons and Holes in Semiconductors D. The blue and red areas represent the hole accumulation and depletion, respectively. For the Fe L -edge XMCD measurements, four x-ray absorption spectroscopy XAS mahnetic were taken by inverting the external magnetic field and the helicity of x rays independently, and then were averaged.
For a system with C 4 v symmetry, as is the case with our system, the above-described equation for T can be simplified as. Additional information How to cite this article: All of these phenomena are attributable to one or both of two factors: Even in the averaged results, voltage applications mmagnetic not contribute significant differences to the orbital magnetic moment. These physical parameters were obtained by performing the X-ray absorption spectroscopy experiment.
All the measurements were performed at room temperature. B 59— The authors declare no competing financial interests. Magneto-ionic control of interfacial magnetism.