Since there is a strong relation between the material characteristics and the crystal orientation of metals and many other industrial materials, quantitative analyses of crystallites orientation and their distributions are of great importance. Pole figure measurements are a common method to quantitatively analyze orientation. In this Application Byte, we used the Orientation Distribution Function (ODF) to evaluate the crystallites orientation of a Cu wiring film from a pole figure measurement.
Quantitative analysis by powder X-ray diffraction has long been carried out using calibration curves, a
technique that requires preparing samples whose components are quantified, using pure or standard
substances to obtain calibration curves. In recent years, quantitative analysis without calibration curves has
become possible by calculating quantitative values from crystal structures. However, these methods require
the crystal structures of the materials, limiting the applicable substances. With the Direct Derivation method
introduced here, the quantitative weight fractions of individual crystalline phases can be derived from sets of
integrated intensities collected in a wide 2 range, together with chemical composition data.
The Oido tunnel tombs in Wakuyacho, Miyagi (Japan) are tumuli that have been constructed between the late 7th century and the early 8th century. During scientific investigations between 1962 and 1964, a glass bead with a spotted pattern (concentric circles) rare to Japan was excavated, which is believed to be originated in South Asia or Southeast Asia. By evaluating the colored portion of the glass bead using the SmartLab Automated Multipurpose X-ray Diffractometer, it was possible to determine its chemical composition and provide a scientific basis for assumptions on the fabrication technique and a reevaluation of its origin. The research was conducted by the Nara National Research Institute for Cultural Properties in 2013, and presented at the 31st Congress of the Japan Society for Scientific Studies on Cultural Properties in 2014.
Thin films formed on substrates show various crystal phase and orientations depending on the materials and
manufacturing method. Therefore, phase identification is sometimes difficult by ordinary X-ray diffraction
(XRD) measurement. The diffraction image using a two-dimensional (2D) detector reveals the lattice constant
and the orientation for each crystal phase readily because the diffraction intensity distribution in the 2θ
direction and the distribution of the crystal orientation in the χ direction are observed simultaneously.
The crystal systems of pharmaceuticals and foods may change due to factors such as temperature and humidity. The
climate of Japan in particular exhibits extreme changes in temperature and humidity, with hot and humid summers, and dry, low-temperature winters, and these are poor conditions as an environment for synthesizing pharmaceuticals or storing foods. Therefore, there is a need to conduct measurement beforehand under various atmospheric conditions, and determine what sort of changes these materials undergo in the actual environment. Thus we evaluated thermal changes and changes in the crystal structure of pharmaceuticals by simultaneously measuring X-ray diffraction (XRD) and differential scanning calorimetry (DSC) while varying humidity.
In order to develop new materials that have desired properties, it is essential to evaluate the materials under
various atmospheric environments. The infrared heating high-temperature attachment Reactor X has a
corrosion-resistant sample chamber separated from the heater section, so it can be used to perform
high-temperature XRD measurements under various atmospheres, such as hydrogen, ammonia, high
humidity and so forth. Using Reactor X with a 2D detector capable of high-speed XRD measurement, it is
possible to investigate in detail rapid phase transitions under heating in various atmospheres.
In the tableting process for pharmaceuticals, it sometimes happens that the active pharmaceutical ingredient reacts with materials used as excipients, such as sugar or starch, and dehydration reactions, polymorph transitions and other processes may occur due to the pressure during tableting. In recent years, a need has arisen to check, in the shortest possible time, whether or not the active pharmaceutical ingredient maintains its original crystal system, and whether or not there are polymorph impurities. Furthermore, this must be done in the tableting process, while maintaining the tablet form. Therefore, we used a powder X-ray diffractometer to non-destructively measure the state of tablets in their original form, and evaluate the presence of the contained active pharmaceutical ingredient and polymorph impurities. By using a transmission-type parallel beam optical system, it is possible to obtain an accurate diffraction profile which does not depend on the sample form, and acquire information not only from the outside, but also from the inside of tablets. As a result of measurement, it was found that if polymorph impurities of the active pharmaceutical ingredient are about 1%, then their presence in the tablets could be confirmed in a measurement time of less than 10 minutes.
Carbide tools used for cutting are provided with various types of coatings to improve durability. Previously, evaluation of the coating layer has been done using X-ray diffraction, but some users want to achieve rapid and simultaneous evaluation of factors such as site-dependent differences in composition, crystallinity and orientation. These evaluations can be easily done by employing the optical element and detector used in this report.
Bulk samples such as metal blocks, ceramic sintered bodies, or pharmaceutical tablets are aggregates of
microcrystals that can be measured by powder X-ray diffraction. In conventional powder diffraction
measurements, samples need to be filled into a sample holder the size of a typical coin and placed in the
center of the diffractometer. Hence, to perform measurements of bulk samples, it has been necessary to cut
or pulverize samples according to the sample holder, or to use an attachment with an electrically driven
adjustment axis in the thickness direction of the sample. With Rigaku’s bulk sample holder, thick bulk samples
can be easily placed in the diffractometer without any need to cut or pulverize, making it possible to identify
crystal phases of bulk surfaces in a non-destructive manner.
Controlling the state of the charge-discharge process is believed to be crucial for extending the life of lithium ion batteries. Therefore, it is not enough to simply observe the electrode structure in the 100% charged and discharged states, and there is a need to carry out in-situ observation of the relationship between depth of charge, depth of discharge and electrode structure. However, if materials are removed once from sealed batteries, the materials will react with the atmosphere, and the charge-discharge state will change due to peeling of electrodes. Thus there is a risk of the material changing into another structure, irrespective of the charge-discharge situation. As a result, with previous methods, it was difficult to observe changes in materials accompanying charging-discharging via an X-ray diffraction measurement. However, with batteries made using lithium ion battery cells for evaluation and testing, X-ray diffraction can be performed simultaneously with charge-discharge testing. Thus it is possible to carry out evaluation by directly relating changes in the state of samples to charge-discharge characteristics, without performing any additional work on the materials subjected to charge-discharge testing, such as opening seals or peeling electrodes.
To capture the moment when materials change, such as during melting, solidification or crystal phase change,
by in-situ X-ray diffraction measurement, the acquisition time of the X-ray diffraction images at each
temperature needs to be as short as possible. 0D and 1D detectors take time to scan the detector and
prepare for operation. Conventional 2D detectors also have a problem in that the X-ray shutter needs to be
opened and closed between counting and reading the data. The HyPix-3000 hybrid pixel array
multi-dimensional detector in 2D mode can acquire X-ray diffraction images without scanning the detector.
The HyPix-3000 has two counters inside. Switching between them allows measurement without dead time.
These features enable shutterless measurement of 2D X-ray diffraction images, which makes it possible to
observe rapid changes in crystalline state.
Reciprocal space mapping (RSM) is an XRD technique used to evaluate lattice spacing and crystal orientation
distribution independently from each other, applied to the analysis of thin film samples such as epitaxial films.
Since a reciprocal space map requires multiple scans with various combinations of the scattering angle (2θ)
and the incident angle with respect to the sample (ω), it can take a relatively long time to collect the necessary
data in general. Combination of the 1D exposure mode of a 2D detector and high-speed scanning by the ω
axis enables data collection in a very short time, from several tens of seconds to several minutes,
The organic semiconductor pentacene has attracted a lot of attention for potential use in TFT (thin film
transistor) due to its high carrier mobility which approaches that of amorphous Si. However, controlling the
crystal phase and molecular orientation in the pentacene thin film is essential to obtain optimal characteristics.
In this example, we perform phase identification and evaluation of orientation of the pentacene molecules in
thin films different in thicknesses as well as crystallite size determination.
X-ray diffraction measurements were carried out on two types of MCM-41. The d values in Fig. 1 do not arise from the atomic structure. They arise from the arrangement of the skeletal structure of the material, and therefore the values are large. As a result, the observed diffraction lines appear on the low angle side, as shown in Fig. 2. Transmission method measurement employing a small-angle optical system is also sometimes used with these samples, but measurement can also be done with a reflection method using a D/teX Ultra the high-speed 1D X-ray detector. As shown in Fig. 2, there is little statistical fluctuation, even with measurement time of 1 minute or less, and the minimum peak positions of d2 and d3 on the large-angle side can be clearly calculated. As shown in Table 1, the relative d values matched theoretical values for both Sample 1 and 2.
In quantitative analysis using X-ray diffractometry, different quantification methods are used depending on factors such as the state of the sample and concentration of the measured components. The method using calibration curves is complicated by the need to procure standard samples, or prepare and measure samples, and thus, at present, there is a switch toward analysis using the WPPF (Whole Powder Pattern Fitting) method and the RIR (Reference Intensity Ratio) method. In the WPPF method, profile fitting is performed over a comparatively broad angular range, based on information about the crystal system and lattice constants. The RIR method uses RIR values listed in a database and integrated intensity of the maximum intensity curves. Both methods enable easy calculation of quantitative values by using dedicated analysis software.