Fe polarization dependent synchrotron Mssbauer spectroscopy using a diamond phase plate and an iron borate nuclear Bragg monochromator

Mitsui, Takaya; Imai, Yasuhiko*; Masuda, Ryo*; Seto, Makoto*; Mibu, Ko*

Journal of Synchrotron Radiation, 22(2), p.427 - 435, 2015/03

https://doi.org/10.1107/S1600577514028306

Grazing-incidence synchrotron-radiation Fe-Mssbauer spectroscopy using a nuclear Bragg monochromator and its application to the study of magnetic thin films

Mitsui, Takaya; Masuda, Ryo*; Seto, Makoto; Suharyadi, E.*; Mibu, Ko*

Journal of Synchrotron Radiation, 19(2), p.198 - 204, 2012/03

https://doi.org/10.1107/S0909049511049958

An energy-domain grazing-incidence Fe-Mssbauer spectroscopy(E-GIMS) with synchrotron radiation (SR) has been developed to studysurface and interface structures of thin films. A high-brilliant Fe-Mssbauer radiation, filtered from SR by a FeBO single crystal nuclear Bragg monochromator (NBM), allows us to perform the conventional Mssbauer spectroscopy (MS) for the dilute Fe in a mirror-like film in any bunch-mode operation of SR. Theoretical and experimental study of the specular reflections from isotope-enriched (Fe: 95%) and natural-abundance (Fe: 2%) iron thin films has been carried out to clarify the basic features of coherent interference between electronic and nuclear resonant scattering of Fe-Mo"ssbauer radiation in thin films. Moreover, a new surface and interface sensitive method has been developed by the combination of SR based E-GIMS and Fe-probe layer technique, which enables us to probe interfacial complex magnetic structures in thin film with atomic-scale depth resolution.

Magnetic structure of spin-density waves in Cr(001)/Sn multilayers with periodic monatomic spacer layers of nonmagnetic Sn

Takeda, Masayasu; Mibu, Ko*; Shinjo, Teruya*; Endo, Yasuo*; Suzuki, Junichi

Physical Review B, 70(10), p.104408_1 - 104408_9, 2004/09

https://doi.org/10.1103/PhysRevB.70.104408

Detailed magnetic structure of spin-density waves (SDWs) in epitaxial Cr(001)/Sn multilayer was investigated by neutron scattering combined with Mssbauer spectroscopic studies. Monatomic Sn layers were embedded in 240 nm thick Cr(001) films with varying the periodic spacing from 4.2 to 16.2 nm. All samples were revealed to be a commensurate antiferromagnetic (CAF) phase at 300 K. The CAF structures changed to incommensurate SDW states with complex waveforms whose wavelength are controlled by the artificial periodicity at low temperatures although the CAF structure in the sample with the period of 4.2 nm persisted even at 10 K. The phase transition depends on the thickness of the Cr layers intervening between Sn monatomic layers. An appreciable phase slip in the SDW was observed during the phase transition in the sample with the period of 10.2 nm. The SDW structure is discussed by taking account of the competing forces between the nesting of Fermi surface and a pinning of antinodes at the Sn monatomic layers.

Competition between interface effect and nesting effect in Cr-based multilayers with monatomic layers of X (X = Sn, Au, Ag, V, or Fe)

Mibu, Ko*; Jiko, Norihiro*; Otsuka, Yuhei*; Takeda, Masayasu

no journal, , 

Magnetic structures of epitaxial Cr(001)/X multilayers, where monatomic layers of X (X = Sn, Au, Ag, V, or Fe) are periodically embedded in Cr, have been studied by neutron diffraction measurements using a triple-axis spectrometer. The temperature dependence of neutron diffraction patterns around the Cr(100) and Cr(010) reciprocal points, where magnetic peaks due to antiferromagnetic structures appear, was compared for Cr(001)/X multilayers with the same layer thickness, e.g., for [Cr(16.0 nm)/X(0.2 nm)] multilayers. It was clearly shown that the spin structure of Cr is quite different dependent on the monatomic counter metal, even when the Cr layer thickness is the same. The results are interpreted as a consequence of a competition between the interface effect, which enhances or quenches the magnetic moment of Cr at the interface regions, and the nesting effect, which stabilizes the incommensurate SDW structure with the modulation along the [001] axis.

Spherical neutron polarization analysis of artificially confined spin-density waves and a phase slip transition in Cr/Sn multilayers

Takeda, Masayasu; Kakurai, Kazuhisa; Mibu, Ko*

no journal, , 

no abstracts in English

Polarization dependent synchrotron Mssbauer spectroscopy with diamond phase retarder and nuclear Bragg monochromator

Mitsui, Takaya; Imai, Yasuhiko*; Seto, Makoto*; Hirao, Naohisa*; Matsuoka, Takehiro*; Mibu, Ko*

no journal, , 

no abstracts in English