arXiv subjects

F. Kuroda

Publications and source records attributed to F. Kuroda.

3 recordsLinked to original sources

arXiv2018

Half-metallicity of Mn2VAl ferrimagnet revealed by resonant inelastic soft x-ray scattering under magnetic field

Detailed information on the electronic states of both V and Mn 3d electrons in the ferrimagnet Mn2VAl is obtained by the bulk sensitive resonant inelastic soft x-ray scattering (SX-RIXS) excited with the circularly polarized light under an external magnetic field for the first time. The results under the V L-edge excitation have revealed the negligible partial density of states (PDOS) of the V 3d states around the Fermi energy as well as their rather localized character. Under the Mn L-edge excitation, on the other hand, the spectra are dominated by fluorescence with clear magnetic circular dichroism with noticeable excitation photon energy dependence. Compared with the theoretical prediction of the RIXS spectra based on the density-functional-theory band structure calculation, an itinerant, spin-dependent character of the Mn 3d states and decays of the Mn 2p core states are confirmed in consistence with the half-metallicity of the Mn 3d states.

cond-mat.mtrl-sci↗

arXiv2018

Anomalous Hall conductivity and electronic structures of Si-substituted Mn$_{2}$CoAl epitaxial films

We study anomalous Hall conductivity ($σ$$_{\rm AHC}$) and electronic band structures of Si-substituted Mn$_{2}$CoAl (Mn$_{2}$CoAl$_{1-x}$Si$_{x}$). First-principles calculations reveal that the electronic band structure is like a spin-gapless system even after substituting a quaternary element of Si for Al up to $x = $0.2 in Mn$_{2}$CoAl$_{1-x}$Si$_{x}$. This means that the Si substitution enables the Fermi level shift without largely changing the electronic structures in Mn$_{2}$CoAl. By using molecular beam epitaxy (MBE) techniques, Mn$_{2}$CoAl$_{1-x}$Si$_{x}$ epitaxial films can be grown, leading to the systematic control of $x$ (0 $\le$ $x$ $\le$ 0.3). In addition to the electrical conductivity, the values of $σ$$_{\rm AHC}$ for the Mn$_{2}$CoAl$_{1-x}$Si$_{x}$ films are similar to those in Mn$_{2}$CoAl films shown in previous reports. We note that a very small $σ$$_{\rm AHC}$ of $\sim$ 1.1 S/cm is obtained for $x =$ 0.225 and the sign of $σ$$_{\rm AHC}$ is changed from positive to negative at around $x =$ 0.25. We discuss the origin of the sign reversal of $σ$$_{\rm AHC}$ as a consequence of the Fermi level shift in MCA. Considering the presence of the structural disorder in the Mn$_{2}$CoAl$_{1-x}$Si$_{x}$ films, we can conclude that the small value and sign reversal of $σ$$_{\rm AHC}$ are not related to the characteristics of spin-gapless semiconductors.

cond-mat.mtrl-sci↗

arXiv2017

Electronic Structure and Magnetic Properties of Half-metallic Ferrimagnet Mn$_{2}$VAl Probed by Soft X-ray Spectroscopies

We have studied the electronic structure of ferrimagnetic Mn2VAl single crystal by means of soft X-ray absorption spectroscopy (XAS), X-ray absorption magnetic circular dichroism (XMCD) and resonant soft X-ray inelastic scattering (RIXS). We have successfully observed the XMCD signals for all constitute elements, supporting the spin polarized states at the Fermi level. The Mn $L_{2,3}$ XAS and XMCD spectra are reproduced by the spectral simulation based on density-functional theory (DFT), indicating itinerant character of the Mn 3d states. On the other hand, V $3d$ electrons are rather localized since the ionic model can qualitatively explain the V $L_{2,3}$ XAS and XMCD spectra as well as the local dd excitation revealed by V $L_3$ RIXS.

cond-mat.str-el↗