Single Crystal Orientation Research Articles

Mitigating CMAS Attack in Model YAlO3 Environmental Barrier Coatings: Effect of YAlO3 Crystal Orientation on Apatite Nucleation

Environmental barrier coatings (EBCs) are used to protect ceramic-matrix composites from undesirable reactions with steam and calcia–magnesia–alumina–silicate (CMAS) particulates found in gas-turbine engine environments. Effective EBCs contain yttria or rare earth ions that will react with molten CMAS to form a protective apatite layer that prevents further attack. Methods to improve the EBCs’ CMAS mitigation capabilities focus on improving the apatite yield but neglect optimizing the apatite formation behavior. This study investigates the effect of apatite nucleation behavior on CMAS penetration by comparing the CMAS attack at 1350 °C of four different single crystal orientations of yttria aluminate perovskite (YAP), a promising EBC candidate. The EBC/CMAS interfacial energy and, thus, reaction behavior varies with YAP orientation. In regions with low CMAS loading, rapid apatite growth is seen on YAP substrates with orientations associated with high EBC/CMAS interfacial energy. However, CMAS penetration is most significant in these samples because the apatite growth is facilitated by recession of the YAP substrate nearby. Such behavior is not observed in regions with high CMAS loading where small apatite crystals form on top of an yttrium aluminate garnet (Y3Al5O12, YAG) phase. This study shows that strategies that control the nucleation and growth of apatite will provide better protection against CMAS.

Field-Tuning Mechanisms of Spin Switching and Spin Reorientation Transition in Praseodymium-Erbium Orthoferrite Single Crystals.

Field-tuning mechanisms of spin switching and spin reorientation (SR) transition were investigated in a series of high-quality single crystal samples of PrxEr1-xFeO3 (x = 0, 0.1, 0.3, 0.5) prepared using the optical floating zone method. The single crystal quality, structure, and axis orientation were determined by room-temperature powder X-ray diffraction, back-reflection Laue X-ray diffraction, and Raman scattering at room temperature. Magnetic measurements indicate that the type and temperature region of SR transition are tuned by introducing different ratios of Pr3+ doping (x = 0, 0.1, 0.3, 0.5). The trigger temperatures of spin switching and magnetization compensation temperature of PrxEr1-xFeO3 crystals can be adjusted by doping with different proportions of Pr3+. Furthermore, the trigger temperature of the two types of spin switching in Pr0.3Er0.7FeO3 along the a-axis can be regulated by an external field. Meanwhile, the isothermal magnetic field-triggered spin switching effect is also observed along the a and c-axes of Pr0.3Er0.7FeO3. An in-depth understanding of the magnetic coupling and competition between the R3+ and Fe3+ magnetic sublattices, within the RFeO3 system, has important implications for advancing the practical applications of the relevant spin switching materials.

Effect of a weak magnetic field on ductile–brittle transition in micro-cutting of single-crystal calcium fluoride

• A weak magnetic field can enhance ductile-mode cutting of CaF 2 single crystal. • Magnetic field direction shows anisotropy in affecting ductile–brittle transition. • A coupled analysis of magneto-plasticity and crystal plasticity is developed. • Dislocation behaviour and fracture toughness are revealed under magnetic field. • DFT computation corroborates the magnetic-induced dislocation depinning theory. Magneto-plasticity occurs when a weak magnetic field alters material plasticity and offers a viable solution to enhance ductile-mode cutting of brittle materials. This study demonstrates the susceptibility of non-magnetic single-crystal calcium fluoride (CaF 2 ) to the magneto-plastic effect. The influence of magneto-plasticity on CaF 2 was confirmed in micro-deformation tests under a weak magnetic field of 20 mT. The surface pile-up effect was weakened by 10–15 nm along with an enlarged plastic zone and suppressed crack propagation under the influence of the magnetic field. Micro-cutting tests along different crystal orientations on the ( 111 ) plane of CaF 2 revealed an increase in the ductile–brittle transition of the machined surface with the aid of magneto-plasticity where the largest increase in ductile–brittle transition occurred along the [ 11 2 ¯ ] orientation from 512 nm to a range of 664–806 nm. Meanwhile, the subsurface damage layer was concurrently thinner under magnetic influence. An anisotropic influence of the magnetic field relative to the single-crystal orientation and the cutting direction was also observed. An analytical model was derived to determine an orientation factor M that successfully describes the anisotropy while considering the single-crystal dislocation behaviour, material fracture toughness, and the orientation of the magnetic field. Previously suggested theoretical mechanism of magneto-plasticity via formation of non-singlet electronic states in defected configurations was confirmed with density functional theory calculations. The successful findings on the influence of a weak magnetic field on plasticity present an opportunity for the adoption of magnetic-assisted micro-cutting of non-magnetic materials.

Laser Thermal Treatment‐Induced MgxZn1−xO Gradient Film and Photodetector with Solar‐Blind UV Response

Mg x Zn1−x O is a ternary oxide semiconductor, which has an important application prospect in solar‐blind UV detection fields. Herein, Mg x Zn1−x O gradient film is realized utilizing the sol–gel method and laser thermal treatment process. X‐ray diffraction (XRD) pattern and absorption curve show that the gradient film has a single (002) crystal orientation and a single absorption edge. Field‐emission scanning electron microscope and energy‐dispersive spectroscopy characterization and finite‐element analysis simulation prove that the laser thermal treatment temperature on the gradient film decreases from 1100 to 600 °C, corresponding to the Mg2+ component gradually increasing from 35% to 54% and the bandgap broadening from 3.75 to 5.08 eV. Metal–semiconductor–metal‐structured photodetectors (PDs) are fabricated based on the gradient film. The high responsivity is attributed to the capture and the prolonged lifetime of photogenerated holes. Herein, an idea for the preparation of gradient film and the development of UVC and UVA multiband PDs is provided.

Disordering of β-Ga2O3 upon irradiation with Si+ ions: Effect of surface orientation

Development of gallium oxide-based devices is one of the most promising areas of modern electronic technology. The method of ion implantation is widely used in electronic engineering; however, it has not yet been sufficiently studied for gallium oxide from a physical point of view. One of the interesting questions is the possible impact of surface orientation of β-Ga2O3 single crystals on the structural damage upon ion irradiation. In this work, the effect of Si+ ion irradiation on the structural properties of β-Ga2O3 crystals with (−201) and (010) surface orientations has been investigated by X-ray diffraction and small-angle reflection electronography. It is established that mechanical stresses in the irradiated layer depend on surface orientation: in the case of (−201) orientation, the stress in lateral to the surface direction is compressive, while it is tensile for the (010) orientation. At one and the same irradiation dose, the degree of damage for (010) orientation is shown to be stronger than that for (−201). Possible explanation is suggested for the surface orientation effect.

Molecular beam epitaxy of single-crystalline bixbyite (In1−xGax)2O3 films ( x≤0.18 ): Structural properties and consequences of compositional inhomogeneity

In this work, we show the heteroepitaxial growth of single-crystalline bixbyite (In$_{1-x}$Ga$_x$)$_2$O$_3$ films on (111)-oriented yttria-stabilized zirconia substrates using plasma-assisted molecular beam epitaxy under various growth conditions. A pure In$_2$O$_3$ buffer layer between the substrate and (In$_{1-x}$Ga$_x$)$_2$O$_3$ alloy is shown to result in smoother film surfaces and significantly improved crystallinity. Symmetric out-of-plane 2$\theta - \omega$ x-ray diffraction scans show a single (111) crystal orientation and transmission electron microscopy confirms the single-crystallinity up to $x = 0.18$ and only slight film quality deterioration with increasing Ga content. Partially relaxed layers are demonstrated via reciprocal space mapping with lattice parameters fitting well to Vegard's law. However, the Ga cations are not evenly distributed within the films containing nominally $x > 0.11$: inclusions with high Ga density up to $x = 0.50$ are observed within a "matrix" with $x \approx 0.08$. The cubic bixbyite phase is preserved, in both the "matrix" and the inclusions. Moreover, for $x \geq 0.11$, both the Raman phonon lines as well as the optical absorption onset remain nearly constant. Hard x-ray photoelectron spectroscopy measurements also indicate a widening of the band gap and exhibit similar saturation of the Ga 2p core level position for high Ga contents. This saturation behavior of the spectroscopic properties further supports the limited Ga incorporation into the "matrix" of the film.

Predicting extreme anisotropy and shape variations in impact testing of tantalum single crystals

Recent Taylor cylinder impact tests carried out for Ta single crystals showed strong variations in dimensional changes for different crystallographic directions aligned with the cylindrical axis. In order to capture the effect of crystallography on the deformation characteristics and final shapes of the impacted cylinders, a single crystal material subroutine is adapted and embedded in the solid mechanics/dynamics Finite Element solver Abaqus to simulate the aforementioned single crystal Ta Taylor impact experiments. Details of the coupled model implementation, and insights on the role played by single crystal anisotropic flow on the deformation behavior across a broad range of strain rates and temperatures for different single crystal orientations are presented and discussed. We demonstrate the predictive capability of the adopted crystal plasticity model to capture the significant role played by crystal orientation-induced anisotropy, as well as strain hardening and adiabatic heating, on the dynamic deformation response of crystalline materials. This re-emphasizes the need of microstructure-aware models to improve the accuracy of simulations for high-consequence engineering design.

The degree of polarization of Raman scattering of light in silicon nanocrystals

Raman scattering of light (RS) on an array of oriented silicon nanocrystals was studied experimentally. The angular dependence of the intensity of the polarized components of the RS was measured and the parameter of the degree of polarization of scattered light was determined. It was found that the degree of polarization of the RS is related to the size of the nanocrystals in the samples. An array of nanocrystals with the same crystallographic orientation was obtained by thermal annealing of a silicon single crystal damaged by ion implantation. During thermal annealing of the sample, the crystallinity of the layer is restored not simultaneously in the entire damaged volume, but in the form of nanocrystals separated by amorphous area. All the clusters formed have the same crystallographic orientation of the original single crystal. The features of the degree of polarization of the RS in nanocrystals are associated with the quantum-mechanical uncertainty of the phonon wave vector and the uncertainty of the phonon direction in a limited volume of the nanocrystal. The relations linking the degree of polarization of the RS with the size of nanocrystals are obtained. A technique for determining the size of nanocrystals by measuring the degree of polarization of the RS is discussed. Keywords: Raman scattering of light, silicon, nanocrystals, ion implantation, annealing, amorphous phase.

Single-Crystal Quality Detection and Evaluation Algorithms Applied to Roller Mill Orientation Instrument

The roller mill orientation instrument (RMOI) integrates the processing and the orientation of single-crystal bars. This type of equipment realizes the integration of two processes: grinding of the single-crystal ingot and orientation of the single-crystal bar. This integration enhances production efficiency and the precision of the orientation. However, this type of approach has two significant constraints: 1) there is no quality detection algorithm for the plane of the crystal bar; it is, therefore, currently necessary to randomly find a crystal plane for orientation, which means that there is no guarantee of the quality of the plane after cutting and 2) there is a lack of evaluation methods to determine the overall quality of the crystal bar. This affects the production process and the requirements for the quality of the crystal bar and further affects the popularization and application of the equipment. Here, to overcome these constraints, we first propose a deep learning 1-D convolutional neural network (1-D-CNN) algorithm to perform feature extraction and supervised classification based on the rocking curve of the single crystal. In sharp contrast to the shallow learning method support vector machine (SVM), SVM feature extraction is insufficient, and the accuracy is low. The average accuracy of 1-D-CNN is 92.00%. This realizes the quality requirements for the successful detection of the crystal plane. Next, using the obtained quality detection results of each crystal plane, a hybrid algorithm combining improved Canopy (ICanopy) and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${K}$ </tex-math></inline-formula> -means algorithms is presented, which improved the average accuracy by 10% compared with the traditional Canopy- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${K}$ </tex-math></inline-formula> -means algorithm, and the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> -nearest neighbor ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> NN) algorithm is further utilized. Finally, an ICanopy- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${K}$ </tex-math></inline-formula> -means- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> NN algorithm is formed, which realizes the overall quality evaluation of the crystal bar under various situations, and the average accuracy increases by 3.33%–90%. The effectiveness of the proposed algorithms is demonstrated by the analysis of results obtained from practical data.

Mapping of Grain Orientation In Situ of 2D Perovskite Thin Films with Low-Frequency Polarized Raman Microspectroscopy

Recent developments in two-dimensional (2D) Ruddlesden–Popper perovskites have ushered in a new phase in optoelectronics through their promising physical, chemical, and optical properties. Thin films of 2D perovskites used in most optoelectronic applications contain many grains oriented either horizontally or vertically with respect to the substrate on which they grow; the orientation of such grains plays important roles, not yet fully understood, in their functionalities. Techniques to map the grain orientation in situ in 2D perovskite thin films are hence highly desirable. Here we report mapping of the grain orientation of thin films of the horizontal 2D perovskite, BA2PbI4, in which BA is butylammonium, with low-frequency polarized Raman microspectroscopy. We established a relation between the intensities of low-frequency (10–60 cm–1) polarized Raman lines of BA2PbI4 originating primarily from the PbI6 octahedra and varied orientations of a plate-like BA2PbI4 single crystal. This relation served to determine unambiguously the orientation of grains of micrometer size in a spin-coated BA2PbI4 thin film. Although this study is a case study of BA2PbI4, it opens a new window to obtain crystallographic information about 2D perovskite thin films in general and hence to understand their properties and functions.

Effect of single-crystal orientation on the molybdenum structure and hardness upon high pressure torsion

The effect of the initial orientation on structure development upon severe plastic deformation performed by high pressure torsion at room temperature has been investigated on molybdenum single crystals of two orientations (110) and (113). The initial orientation of molybdenum has been found to affect its deformability, texture, and the size of structural elements significantly only at the initial stages of deformation. Single crystal with the (113) orientation is more stable to deformation. Its fragmentation starts at a higher true strain than the fragmentation of the single crystal with the (110) orientation. An increase in the true strain above 6 completely neutralizes the effect of the initial orientation on the structure development.

Improved growth quality of epitaxial ZnTe thin films on Si (111) wafer with ZnSe buffer layer

To achieve high-quality and low-cost ZnTe epitaxial films, a low-temperature (LT, 200 °C) ZnSe buffer layer with a thickness of 5 nm was grown on Si (111) wafers prior to the epitaxy of ZnTe layers by molecular beam epitaxy. Reflection high-energy electron diffraction patterns reveal that ZnTe epilayers grown at 335 °C with a thickness of 100 nm on the LT-ZnSe buffer layer present a completely two-dimensional growth mode. Film surfaces present smooth and flat morphology with the lowest surface roughness of ∼2.2 nm at a Te/Zn beam equivalent pressure ratio of 1.6. X-ray diffraction θ-2θ scanning indicates that the out-of-plane structure of ZnTe films is highly preferred with the (111) growth orientation of ZnSe/Si. X-ray diffraction φ scanning further confirms that the in-plane structure of ZnTe epilayer is also a single-crystal orientation growth. Thus, high-quality ZnTe (111) single-crystal epilayer with the lowest full-width at half-maximum of ∼200 arc sec and the smallest dislocation density of ∼1.12 × 108 cm−2 was grown on Si (111) wafers. In addition, the ZnSe buffer layer could alleviate the residual stress effectively for the heteroepitaxy of Si wafers. The most balanced residual stress for ZnTe/ZnSe/Si with σx of ∼96.5 MPa and σy of ∼94.2 MPa was obtained, which is essential for achieving high-performance and good mechanical properties of ZnTe-based devices.

Size-dependent vibration of single-crystalline rectangular nanoplates with cubic anisotropy considering surface stress and nonlocal elasticity effects

The presented paper investigates size-dependent vibration of single-crystalline rectangular nanoplates with cubic anisotropy based on combined surface stress and nonlocal elasticity effects. For this, the fundamental equations are derived with a discussion about the anisotropy formulations. The generalized differential quadrature method (GDQM) is used to solve the differential equation for applicable boundary conditions. The convergence and stability of the results are verified to obtain a suitable number of grid points. At first, the effective Young’s modulus versus the thickness is verified by the existing experiments. Then, the problem is simulated for a complete set of single crystal orientation and a wide range of size scale parameters and material types. The results indicate that size scale parameters have different vibration effects at different material orientations and boundary conditions. The size-scale effects decrease the natural frequency of CCFF (two edges clamped) and CCCC (fully clamped) nanoplates rotates from [100] to [110] axis for FCC (Face Centered Cubic ) materials in contrast with cantilevered nanoplates (CFFF).

Effect of substrate orientation on crystal growth in selective electron beam melting of nickel-based superalloy

Selective electron beam melting (SEBM) has proven to be a possible method for fabricating single-crystal structures owing to its high preheating temperature and directional temperature gradient, which can promote the directional growth of columnar grains. Researchers have conducted experiments to obtain a CMSX-4 single-crystal structure; however, when a polycrystalline substrate was adopted, a 9–15 mm competitive growth stage could not be avoided. There are still two key questions that need to be addressed: 1) Whether the use of a single-crystal substrate can avoid the competitive growth stage and a single-crystal structure grown directly from the substrate, and 2) the effect of single-crystal substrate orientation (001, 001, or 111) on grain growth behavior.Polycrystalline substrates and single-crystal substrates with different crystallographic orientations were used in this study. It was found that the (001) substrate promoted single-crystal structure growth in the SEBM process. When SEBM was carried out with (011) and (111) substrates, because of the complicated temperature field and crystallographic orientation in the first few layers, stray grains were found and epitaxial growth was difficult to maintain. These findings provide an important foundation for the direct fabrication of single-crystal blades.

The ‘effective modulus’ in cubic single crystals subjected to full transverse constraint

The orientation dependence of the ‘effective modulus’ relating the applied stress to the applied strain for a single crystal of a triclinic material subjected to full transverse constraint is specified as a general problem for which special solutions apply when conditions of symmetry exist. When the crystal is cubic and the direction of applied stress is along <100>, <110> or <111> directions, the ‘effective modulus’ is simply the elastic stiffness tensor cij resolved along the direction under consideration. For all other orientations of cubic single crystals, this ‘effective modulus’ can be shown analytically to be less than the elastic stiffness tensor resolved along the direction under consideration.

Probing single crystal orientation by X-ray diffraction for nickel-based superalloys

The deviation angles of Ni-based single crystal superalloys are investigated by two techniques of rotating orientation X-ray diffraction (RO-XRD) and back-reflection Laue X-ray diffraction (BRL-XRD). The remarkable agreement between the RO-XRD and BRL-XRD methods provides strong evidence that the cutting direction has a significant effect on the deviation angle. Regardless of the deviation angle, the primary orientation angle is presented to characterize the inherent orientation changes in Ni-based single crystal superalloy, and it eliminates the effects of cutting direction. Furthermore, two pairs of diffraction peaks of the RO-XRD pattern could be developed in Ni-based single crystal superalloy, although these peaks are generally considered to take place in a bicrystal.

Mechanical characterization of boron carbide single crystals

AbstractOut‐of‐plane anisotropy in the mechanical response of boron carbide was studied by performing nanoindentation experiments on four specific crystallographic orientations of single crystals, that is, , , , and . For each orientation of the single crystals, in‐plane variations of indentation modulus and hardness were also studied by monitoring the relative rotation between the crystal surface and a Berkovich indenter tip. A significant out‐of‐plane anisotropy in indentation modulus was observed with ~80 GPa difference between the highest and lowest values. A smaller but measurable out‐of‐plane anisotropy in indentation hardness was also observed. In‐plane anisotropy, on the other hand, was found to be significantly influenced by the scatter in the data and geometrical imperfections of the indenter tip. Investigations of indentation pop‐in events suggested that deformation is entirely elastic prior to the first pop‐in. Furthermore, quasi‐plastic flow along the orientation of the single crystals was found to be more homogeneous than the other tested orientations. For select indents, cross‐sectional transmission electron microscopy (TEM) of the indented regions showed formation of a quasi‐plastic zone in the form of lattice rotation and various microstructural defects. The quasi‐plastic zone grew in size with increasing the indentation depth. The TEM observations also suggested the crystal slip to be a potential mechanism of quasi‐plasticity and a precursor for formation of amorphous bands that could eventually lead to cracking and fragmentation. The proposed failure mechanism provides valuable insights for calibrating constitutive computational models of failure in boron carbide.

The effect of crystallographic orientation on the transformation of the structure in aluminum single crystals upon exposure to shock waves

In this work, the influence of the crystallographic orientation of high-purity aluminum single crystals of grade A999 on the transformation of the initial structure as a result of exposure to shock waves at a temperature of −196°C was experimentally investigated. It was found that when the shock front propagates in the [110] direction at pressures of 40 GPa and 50 GPa, structural changes in aluminum single crystals are observed in the form of dislocation slip lines along the (111) and (110) planes. The impact of the shock front in the direction of [113] at a pressure of 50 GPa leads to coordination structural changes. It was found that a nanocrystalline structure with an average grain size of 80 nm is formed in the near-surface layers at a depth of 1–3 mm, and a subgrain structure is formed at a depth of 6–7 mm. In fact, a gradient type structure is formed. The reasons for the pronounced effect of the influence of the crystallographic orientation of high-purity aluminum single crystals on structural changes under the action of shock waves are discussed.

Phase-controllable laser thinning in MoTe2

Laser thinning of two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs) has been considered a promising method to tune the bandgaps of TMDs via precise control of their thickness. However, the laser irradiation generates numerous chalcogen vacancies, which are known to cause a phase transition in polymorphic TMDs such as MoTe2. Therefore, the delicate control of the thickness and the phase during laser thinning is highly demanded to study the intrinsic properties of few-layered TMDs. Here, we report power-dependent laser thinning and phase control of semiconducting hexagonal MoTe2 (2H-MoTe2). High-resolution X-ray nano diffraction with synchrotron radiation showed that laser-thinned 2H-MoTe2 with low laser power (<2 mW) retained its hexagonal diffraction patterns with a single crystal orientation. In contrast, a phase transition to monoclinic (1T′) MoTe2 occurred during laser thinning at a high laser power level. Confocal Raman spectroscopy and atomic force microscopy (AFM) revealed that the low-power laser thinning of 2H-MoTe2 retained the crystal structure whereas high-power laser thinning created considerable amount of chalcogen vacancies and a phase transition. Power-dependent laser thinning thus provides a promising way to control the thickness and the phase of polymorphic 2D TMDs for next-generation optoelectronic devices.

(Invited) Novel Technique to Measure Thermal Diffusivity of Soft Crystal in Micro Scale

To control thermal properties in nano- and micro scale is one of the important topics with regards to the phonon engineering. Recently, the mechanical molecular crystals have been developed, which have the potential applications of actuators and soft robots. Most of the crystal motions are induced by photoisomerization or mechanical stress.Thermal phase transition and the photothermal effect are considered as the underlying mechanism for the motions, such as bending, twisting, jumping, and rotating, etc., of the mechanical molecular crystals, called soft crystals. However, due to the lack of the measured data of heat transport properties such as thermal diffusivity or thermal conductivity of single crystals in micro volume size, the quantitative analysis of thermal phenomena in the molecular crystals has not yet been quantitatively analyzed. For example, the photo-thermally induced temperature rise produces the localized temperature distribution near the surface, and thermal diffusivity should be utilized to calculate the temperature distribution in the specimen.To overcome such situation, we propose a micro scale temperature wave analysis (micro-TWA) method to measure the thermal diffusivity of soft crystals in micro scale. (Figure 1) This method enables to measure the axial orientation in single crystals. Furthermore, coupled with the photo-thermal stimulation, the kinetic measurement of thermal diffusivity under the stress induced and photo induced field has been realized. Demonstration of the super elastic phase transition of soft crystal, 3,5- difluorobenzoic acid (3,5−F2bza) and terephthalamide(TPA) will be presented. This is a proposal of the new measurement method, because the experimental determination of the thermal diffusivity in micro scale of organic single crystals, under operating the deformation control, is still a challenge. The experimental validity is discussed with the theoretical analysis using the reference sample. Figure 1