46 research outputs found
Chiral Soliton Lattice Formation in Monoaxial Helimagnet Yb(NiCu)Al
Helical magnetic structures and its responses to external magnetic fields in
Yb(NiCu)Al, with a chiral crystal structure of the space
group , have been investigated by resonant X-ray diffraction. It is shown
that the crystal chirality is reflected to the helicity of the magnetic
structure by a one to one relationship, indicating that there exists an
antisymmetric exchange interaction mediated via the conduction electrons. When
a magnetic field is applied perpendicular to the helical axis ( axis), the
second harmonic peak of develops with increasing the field. The
third harmonic peak of has also been observed for the =0.06
sample. This result provides a strong evidence for the formation of a chiral
magnetic soliton lattice state, a periodic array of the chiral twist of spins,
which has been suggested by the characteristic magnetization curve. The helical
ordering of magnetic octupole moments, accompanying with the magnetic dipole
order, has also been detected.Comment: 13 pages, 18 figures, accepted for publication in J. Phys. Soc. Jp
Identification of microscopic spin-polarization coupling in the ferroelectric phase of a magnetoelectric multiferroic CuFe1-xAlxO2
We have performed synchrotron radiation X-ray and neutron diffraction
measurements on magnetoelectric multiferroic CuFe1-xAlxO2 (x=0.0155), which has
a proper helical magnetic structure with incommensurate propagation wave vector
in the ferroelectric phase. The present measurements revealed that the
ferroelectric phase is accompanied by lattice modulation with a wave number 2q,
where q is the magnetic modulation wave number. We have calculated the Fourier
spectrum of the spatial modulations in the local electric polarization using a
microscopic model proposed by Arima [T. Arima, J. Phys. Soc. Jpn. 76, 073702
(2007)]. Comparing the experimental results with the calculation results, we
found that the origin of the 2q-lattice modulation is not conventional
magnetostriction but the variation in the metal-ligand hybridization between
the magnetic Fe^3+ ions and ligand O^2- ions. Combining the present results
with the results of a previous polarized neutron diffraction study [Nakajima et
al., Phys. Rev. B 77 052401 (2008)], we conclude that the microscopic origin of
the ferroelectricity in CuFe1-xAlxO2 is the variation in the metal-ligand
hybridization with spin-orbit coupling.Comment: 11 pages, 9 figures, to be published in Phys. Rev.
Estimation of spin magnetic moment from x-ray magnetic circularly polarized emission
X線磁気円偏光発光を用いて、金属鉄のスピン磁気モーメントを見積もる方法を開発した。この方法では、オージェ電子分光の解析から得られた2p-3d相互作用を利用しているが、その場合にはスピン磁気モーメントが真の値よりも小さく見積もられたため、2p-3d相互作用を正しく推定する方法が重要であることがわかった。The 19th International Conference on Solid Flilms and Surface
Effect of p-d interaction on circularly polarized Kα emission
X線磁気円偏光発光を用いて、金属鉄における2p-3d相互作用を評価する方法を開発した。その結果、これまでに報告されているオージェ電子分光法の結果と対応した値が得られることがわかった。PF研究会「X線分光理論の新展開:構造・電子状態解析から磁性研究まで」 Frontier of theoretical approaches in x-ray spectroscopie