High-Angular Resolution X-ray Diffraction Equipment

◆Equipment overview

This is a pseudo-six-axis diffractometer with a basic design of a four-axis diffractometer, which can perform precise structural analysis for thin film surfaces. There are also available X-ray beams that are focused to several microns in size.

◆Features of the Equipment

Miltiple-axis diffractometers (Kohzu-Seiki TDT-17) are used for thin film structural analysis and interface structure analysis between thin films and substrates. The control software being used is Spec (https://www.certif.com).
This diffractometer can be used as a standard 4-axis type, as well as a limited 5-axis or 6-axis type. In the case of a 4-axis type, there are 3 degrees of freedom (ω-axis,χ-axis,φ-axis) around the sample, and 1 degree of freedom (δ-axis, or 2θ arm) for the detector. The 2θ arm installed on the detector has a level and rotational driving stage (γ-axis), which allows the detector to have 2 degrees of freedom and a 5-axis diffractometer. Since a light-coded crystal can be installed on the 2θ arm, measurements with reduced background and improved S/N ratio can be performed. If you add the rotation axis (α-axis) of the entire diffractometer used as the incident angle adjustment axis in the micro-angle incident arrangement, it becomes a 6-axis diffractometer. The table shows the minimal resolution of each axis of this diffractometer.

In addition to the double-slit arrangement, a 0.4 degree solar-slit (Huber 3030-I) is also available, which improves the S/N ratio of the X-ray detection. The following equipment is available for detectors: an ion chamber, a silicon PIN photodiode detector, a scintillation detector (Oxford x2000), a silicon drift detector, an imaging plate detector, and a single-photon measurement 2-dimensional detector (Pilatus-100K, HyPix-400).
X-rays in the energy region of 6 keV to 30 keV (up to 50 keV depending on the conditions) are available, with a maximum beam intensity of 6×10¹³ photons/second (＠12.4 keV). The typical beam size used is 100 μm, but a beam of several μm is also available when using a focusing optical system with a refractive X-ray lens.

Table: Minimum resolution of each axis of the multi-axis diffractometer

Axis	Step (arc sec)
ω	0.09
φ	1.7289
ψ	1.8
2θ	0.72
γ	3.96
α	0.144

◆Equipment accessories

In addition to a Helium-Nitrogen flow sample chamber to prevent sample deterioration, a sample chamber with a beryllium window that can be heated up to 550 degrees in a high vacuum is available. Optical microscopes for X-ray irradiation position review, as well as X-ray refraction lenses for generating beams of several μm sizes are also available if necessary. The device features a motor driven adjustment stage with 5 axes (3 translation axes, 2 impact axes) for sample alignment, as well as an incident beam forming slit, and a beam position stabilization system (MOSTAB).

◆Experiment / sample preparation

If the sample substrate size is between 5~10 mm, a standard sample chamber can be installed. If you intend to take measurements beyond this size range, please contact the person in charge of the BL. Prior sample preparation is not required, but every time, at the start of beam time, light sources, optical equipment and diffraction devices are aligned to ensure the angle accuracy of the device.
If you wish to bring in a sample adjustment chamber for measurements, it is necessary to install and adjust in advance to prevent interference with the device.

◆Experimental procedure / precautions

The control software used is Spec (https://www.certif.com), which allows for simple command input that provides easy access to the reciprocal lattice space, where powerful macro functions automate troublesome measurement procedures. On the other hand, please note that the standard user interface is the CUI (Character User Interface).
Since the distance of the sample stage surface to the X-ray irradiation position is 40 mm, if you wish to bring a sample adjustment chamber for measurements, pay close attention to interference with the device.
If you are using this device for the first time, or if you are considering different measurement methods or conditions, in order to effectively implement the experimental objectives, it is recommended that you meet with the person in charge of the BL before applying for the assignment.

◆Contact

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◆List of representative treatises

[1] “Effect of Non-Specifically Adsorbed Ions on the Surface Oxidation of Pt(111)”
M. Nakamura, Y. Nakajima, N. Hoshi, H. Tajiri, and O. Sakata,
ChemPhysChem, vol.14, pp.2426-2431 (2013).
DOI: 10.1002/cphc.201300404

[2] “Nanosecond Phase Transition Dynamics in Compressively Strained Epitaxial BiFeO₃”
M.P. Cosgriff, P. Chen, S.S. Lee, H.J. Lee, L. Pitike, W. Parker, L. Louis, H. Tajiri, S. Nakhmanson, J.Y. Jo, Z. Chen, L. Chen, and P. Evans,
Adv. Electronic Mater., vol.1, pp1500204-(1-9) (2015).
DOI: 10.1002/aelm.201500204

[3] " Large enhancement of bulk spin polarization by suppressing CoMn anti-sites in Co₂Mn(Ge_0.75Ga_0.25) Heusler alloy thin film”
S. Li, Y.K. Takahashi, Y. Sakuraba, N. Tsuji, H. Tajiri, Y. Miura, J. Chen, T. Furubayashi, and K. Hono,
Appl. Phys. Lett., vol. 108, pp122404-(1-5) (2016) .
DOI: 10.1063/1.4944719

[4] “Air/Liquid Interfacial Nanoassembly of Molecular Building Blocks into Preferentially Oriented Porous Organic Nanosheet Crystals via Hydrogen Bonding”
R. Makiura, K. Tsuchiyama, E. Pohl, K. Prassides, O. Sakata, H. Tajiri, and O. Konovalov,
ACS Nano, vol.11 pp10875-10882 (2017).
DOI: 10.1021/acsnano.7b04447

[5] “Effect of hydrophobic cations on the oxygen reduction reaction on single-crystal platinum electrodes”,
T. Kumeda, H. Tajiri, O. Sakata, N. Hoshi, M. Nakamura,
Nature Commun., vol. 9, 4378-(1-7) (2018).
DOI: 10.1038/s41467-018-06917-4