A. Alberca

Crystal symmetry lowering in chiral multiferroic Ba3TaFe3Si2O14 observed by x-ray magnetic scattering

Chiral multiferroic langasites have attracted attention due to their doubly chiral magnetic ground state within an enantiomorphic crystal. We report on a detailed resonant soft x-ray diffraction study of the multiferroic Ba3TaFe3Si2O14 at the FeL2,3 and oxygenK edges. BelowTN (≈27K)we observe the satellite reflections (0,0,τ ), (0,0,2τ ), (0,0,3τ ), and (0,0,1 − 3τ) where τ ≈ 0.140 ± 0.001. The dependence of the scattering intensity on x-ray polarization and azimuthal angle indicate that the odd harmonics are dominated by the out-of-plane (ˆc axis) magnetic dipole while the (0,0,2τ ) originates from the electron density distortions accompanying magnetic order.We observe dissimilar energy dependencies of the diffraction intensity of the purelymagnetic odd-harmonic satellites at the Fe L3 edge. Utilizing first-principles calculations, we show that this is a consequence of the loss of threefold crystal symmetry in the multiferroic phase.

X-ray absorption study of the ferromagnetic Cu moment at the YBa2Cu3O7/La2/3Ca1/3MnO3 interface and variation of its exchange interaction with the Mn moment

With x-ray absorption spectroscopy and polarized neutron reflectometry we studied how the magnetic proximity effect at the interface between the cuprate high-TC superconductor YBa2Cu3O7 (YBCO) and the ferromagnet La2/3Ca1/3MnO3 (LCMO) is related to the electronic and magnetic properties of the LCMO layers. In particular, we explored how the magnitude of the ferromagnetic Cu moment on the YBCO side depends on the strength of the antiferromagnetic (AF) exchange coupling with the Mn moment on the LCMO side. We found that the Cu moment remains sizable if the AF coupling with the Mn moments is strongly reduced or even entirely suppressed. The ferromagnetic order of the Cu moments thus seems to be intrinsic to the interfacial CuO2 planes and related to a weakly ferromagnetic intraplanar exchange interaction. The latter is discussed in terms of the partial occupation of the Cu 3d3z2 - r2 orbitals, which occurs in the context of the so-called orbital reconstruction of the interfacial Cu ions.

X-ray absorption spectroscopy study of the electronic and magnetic proximity effects inYBa2Cu3O7/La2/3Ca1/3MnO3andLa2−xSrxCuO4/La2/3Ca1/3MnO3multilayers

With x-ray absorption spectroscopy we investigated the orbital reconstruction and the induced ferromagnetic moment of the interfacial Cu atoms in YBa

Interplay between magnetic order at Mn and Tm sites alongside the structural distortion in multiferroic films ofo−TmMnO3

_2

YBa2Cu3O7/La2/3Ca1/3MnO3およびLa2-xSrxCuO4/La2/3Ca1/3MnO3多層膜における電子的,磁気的近接効果のX線吸収分光研究

Cu

Crystal symmetry lowering in chiral multiferroic

_3

{\mathrm{Ba}}_{3}{\mathrm{TaFe}}_{3}{\mathrm{Si}}_{2}{\mathrm{O}}_{14}

O

observed by x-ray magnetic scattering

_{7}

X-ray absorption study of the ferromagnetic Cu moment at the

/La

{\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7}/{\mathrm{La}}_{2/3}{\mathrm{Ca}}_{1/3}{\mathrm{MnO}}_{3}

_{2/3}