Photon Factory Activity Report 2005 #23 Part B (2006)
Crystallography

3A, 10A/2005G131

Magnetic ordering in BaTiCoFe10O19 observed byresonant x-ray magnetic scattering
Seiji OHSAWA 1, Maki OKUBE 1, Norio SHIMIZU1, Koichi OHKUBO1,2
3
1
Takeharu MORI , Takeshi TOYODA , Satoshi SASAKI*
1
Materials and Structures Lab., Tokyo Inst. Tech., Nagatsuta, Yokohama 226-0803, Japan
2
KEK-PF, Tsukuba, Ibaraki 305-0801, Japan3
Industrial Research Institute of Ishikawa, Kuratsuki, Kanazawa 920-8203, Japan
Introduction
Resonant x-ray magnetic scattering (RXMS) has
attracted much interest as a useful tool to determine themagnetic structures associated with specific electronic
states such as 3d-4p interactions. The RXMS experimentin ferromagnetic Ni was first made at the Ni K edge [1].
Large resonant exchange scattering was predicted in Land M absorption edges to dominate the magnetic
scattering [2]. The Bragg intensity was estimated withthe resonant enhancement between charge and magnetic
scatterings at the L edge of the rare-earth systems [3].
Various resonant experiments have been carried out forthe x-ray energies near the MIV edges of actinides and near
the LIII edges of rare-earth and transition-metalcompounds [4]. There are not so many reports on the Kedge of 3d transition metal because of relatively weakenhanced intensity. It is now known that magnetic
resonance arises from the spin-orbit coupling at the Kedge through the process of either strongly polarized 3dband or interatomic exchange between 4p and 3d sates[5,6].
In this study, the magnetic structure of M-type
BaTiCoFe10O19 has been examined to confirm thepotential ability of RXMS in the relatively complicatedsystem.
Experimental
Single crystals of BaCoTiFe10O19 were synthesized by aflux method. Diffraction experiments were carried out at
the Fe K absorption edge at BL-3A and BL-10A. The
horizontally
polarized
white
x-raysweremonochromatized by the Si(111) double-crystal
monochromator.
A four-circle geometry at the BL-3A was used for theRXMS study at 100 K. Low-temperature experiments
were performed with the Oxford Cryostream Cooler,
where cold and dry nitrogen gas is directly blown onto
the crystal.
Results and discussion
X-ray diffraction experiments for BaCoTiFe10O19 weremade at a wavelength of λ = 1.7406 Å (E = 7122.8 eV) at
the Fe K edge, based on the characteristic XMCD signals
for the crystals. A magnetic reflection appears at 100 K(Fig. 1), which does not obey the extinction rules of theP63/mmc symmetry and is noted 0 0 8+(2/3). Although

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the satellite reflection associates with the diffuse intensity,
the sharpness of peak is characteristic for a long-range
magnetic order. The appearance of the peak coincides
with the result by the neutron diffraction for
BaCo0.8Ti0.8Fe10.4O19, which was interpreted in terms of amagnetic helix propagated along the hexagonal c axis [7].
Thus, it is conclusive that the Fe K edge can excite
resonantly but indirectly the 3d states and the magnetic
resonant enhancement is sufficiently large to study themagnetic order of Fe compounds.

Fig.1, Scans between 008 and 0 0 10 reflections ofBaCoTiFe10O19. Beside the fundamental reflections, 0 08+(2/3) reflection is observed at T = 100 K. The inset
shows the same measurements on a full scale. The
satellite reflection disappeared at T = 200 K.
References[1] K. Namikawa et al., J. Phys. Soc. Jpn. 54, 4099 (1985).
[2] J. P. Hannon et al., Phys. Rev. Lett. 61, 1245 (1988).
[3] P. Carra et al., Phys. Rev. B 40, 7324 (1989).
[4] D. Gibbs, J. Magn. Magn. Mater. 104-107, 1489
(1992).
[5] W. Neubeck et al., Phys. Rev. B 60, R9912 (1999).
[6] J. Igarashi and M. Takahashi, J. Phys. Soc. Jpn. 69,4087 (2000).
[7] J. Kreisel et al., J. Magn. Magn. Mater. 224, 17 (2001).
* sasaki@n.cc.titech.ac.jp