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This paper presents the transcript of the meeting of former editors-in-chief, the present editor-in-chief, the present executive editor, and the present vice-executive editors, which was held on October 18, 2021.

For two-dimensional electron gas device applications, it is important to understand how electrical-transport properties are controlled by gate voltage. Here, we report gate voltage-controllable hysteresis in the resistance-temperature characteristics of two-dimensional electron gas at LaAlO

The requirements of multifunctionality in thin-film systems have led to the discovery of unique physical properties and degrees of freedom, which exist only in film forms. With progress in growth techniques, one can decrease the film thickness to the scale of a few nanometers (∼nm), where its unique physical properties are still pronounced. Among advanced ultrathin film systems, ferroelectrics have generated tremendous interest. As a prototype ferroelectric, the electrical properties of BaTiO3 (BTO) films have been extensively studied, and it has been theoretically predicted that ferroelectricity sustains down to ∼nm thick films. However, efforts toward determining the minimum thickness for ferroelectric films have been hindered by practical issues surrounding large leakage currents. In this study, we used ∼nm thick BTO films, exhibiting semiconducting characteristics, grown on a LaAlO3/SrTiO3 (LAO/STO) heterostructure. In particular, we utilized two-dimensional electron gas at the LAO/STO heterointerface...

A top gate field effect transistor was fabricated using polymethyl methacrylate (PMMA) as a gate insulator on a LaAlO3 (LAO)/SrTiO3 (STO) hetero-interface. It showed n-type behavior, and a depletion mode was observed at low temperature. The electronic properties of the 2-dimensional electron gas at the LAO/STO hetero-interface were not changed by covering LAO with PMMA following the Au top gate electrode. A split gate device was also fabricated to construct depletion mode by using a narrow constriction between the LAO/STO conduction interface. The depletion mode, as well as superconducting critical current, could be controlled by applying a split gate voltage. Noticeably, the superconducting critical current tended to decrease with decreasing the split gate voltage and finally became zero. These results indicate that a weak-linked Josephson junction can be constructed and destroyed by split gating. This observation opens the possibility of gate-voltage-adjustable quantum devices.

As a quest for two-dimensional conducting interface with exotic functionalities for future electronic devices, the perovskite heterointerface of LaAlO3/SrTiO3 (LAO/STO) has been intensively studied. For the LAO/STO heterostructure, the critical thickness of the LAO layer for metallic conduction is 4 unit cells (uc) according to the polar catastrophe scenario. However, we find that metallic conduction can also be induced at the LAO/STO interface with only 1 uc of LAO, as long as it is capped by 3 or more uc of STO. Consistent results are obtained from density functional theory calculations. For this STO/LAO/STO trilayer, we also confirmed a peculiar non-BCS-type superconductivity with a suppressed superconducting gap, which may imply a superconducting coupling distinct from previously reported BCS-type superconductivity in LAO/STO heterointerface. These observations suggest that the STO/LAO/STO trilayer can be another testing board to explore carrier conduction in two-dimensional electron systems for electronic device applications utilizing exotic functionalities.

We coated inorganic layer containing oxygen, aluminium, phosphorus, and negligible sodium (APO) on stainless steel (STS) by using slot-die coating method and studied its application prospects as a substrate for flexible devices. The APO layer was compositionally uniform in overall area with an amorphous crystal structure. Surface morphology characterization of STS exhibited an improved flatness after the APO layer coating process. The optical property characterization of the APO film carried out by measuring optical reflectance spectrum and refractive index. We also investigated the electrical-transport mechanism in the APO layer. These experimental observations imply the possibility of potential application of APO-STS as a substrate for flexible devices.

High-pressure Brillouin spectroscopy was applied to clarify quantitatively the physical and mechanical differences of a polymer with distinct structures consisting of the same elements. The pressure dependences of elastic properties, Young’s modulus, the shear modulus, the bulk modulus, and Poisson’s ratio for an amorphous poly (-ethylene terephthalate-) [(-PET-)] and a semi-crystalline PET were compared for pressures up to 11 GPa. A collapse of the free volume for the two PETs was ascertained at the different values of the pressure with different slopes for the elastic properties, Young’s modulus, the shear modulus, and the bulk modulus. Although the Poisson’s ratios of a semi-crystalline PET increased linearly with increasing pressure, those of an amorphous PET were almost constant. The P-V equation of state (EOS) for an amorphous PET was also determined, and isothermal bulk moduli extracted from the Birch-Murnaghan and the Vinet EOSs were 6.3 ± 0.2 GPa and 6.7 ± 0.1 GPa, respectively.

The requirements of multifunctionality in thin-film systems have led to the discovery of unique physical properties and degrees of freedom, which exist only in film forms. With progress in growth techniques, one can decrease the film thickness to the scale of a few nanometers (∼nm), where its unique physical properties are still pronounced. Among advanced ultrathin film systems, ferroelectrics have generated tremendous interest. As a prototype ferroelectric, the electrical properties of BaTiO

We grew epitaxial thin films of CoMn2O4 and Co2MnO4 on Nb-doped SrTiO3(011) and SrTiO3(001) single crystal substrates using pulsed laser deposition. The magnetic Curie temperature (T c ) of the Co2MnO4 thin films was ~176 K, which is higher than that of the bulk whereas CoMn2O4 thin films exhibited a value of T c (~151 K) lower than that of the bulk. For the Co2MnO4 thin films, the M − H loop showed a coercive field of ~0.7 T at 10 K, similar to the value for the bulk. However, the M −H loop of the CoMn2O4(0ll) thin film grown on a Nb-doped SrTiO3(011) substrate exhibited a coercive field of ~4.5 T at 30 K, which is significantly higher than those of the Co2MnO4 thin film and bulk. This giant coercive field, only observed for the CoMn2O4(0ll) thin film, can be attributed to the shape anisotropy and strong spin-orbit coupling.

Although the conventional vibrational spectroscopic techniques of Raman and infrared spectroscopy are generally used to analyze the material properties of polymers, the physical and mechanical information that can be obtained through these techniques is very scarce. Since elastic information and equation of state are important for the application of polymers, we carried out Brillouin spectroscopy coupled with a diamond anvil cell. The pressure dependence of elastic properties for an amorphous polycarbonate with and without pressure medium was investigated for pressure up to 11 GPa. A substantial collapse of free volume under the anisotropic pressure was ascertained with the different slopes of elastic constants, Young's moduli, and bulk moduli at low and high pressures. From the Brillouin frequency shifts, we extracted C 11 and C 12 elastic constants, Young's moduli, shear moduli, bulk moduli, Poisson's ratios, and their pressure dependences. P – V isotherms were then constructed and fitted to two semi-empirical equations of state to extract the isothermal bulk modulus and its pressure derivative.

We synthesized orthorhombic SrIrO3 thin films on SrTiO3(001) substrates by employing pulsed laser deposition with systematic variation of the growth temperature and laser fluence. Despite of the different growth conditions, the low temperature resistivity only varies in the mΩ cm range. However, the characteristic temperature dependence varies with the growth condition, and displays the so-called "insulator-like", "intermediate", or "metal-like" behavior. We found that the alternative of metal-like or insulator-like electrical property is relevant to subtle changes in the lattice structure of semi-metallic SrIrO3 likely caused by small rotations of the IrO6 octahedrons.

C), crystal structure became cleared accompanying achange of surface structure. In the temperature dependences of magnetization, phase transitions were observed at ~100 K for bothbefore and after post-growth treated samples which were not observed for the bulk. For both samples, ferromagnetic behaviors wereobserved above 100 K while it turned to ferrimagnetism at low temperature below 100 K. In particular, the ferrimagnetic behaviorbecame strong after the post-growth treatment. These results indicate that the post-growth annealing process plays an important role indetermining the physical properties of spinel CoMn

Thin amorphous silicon (a-Si) films were crystallized into polycrystalline silicon (poly-Si) by combining solid phase crystallization (SPC) and subsequent excimer laser annealing (ELA). Then thin film transistors (TFTs) were fabricated by using the poly-Si formed in the single and double excimer laser scanned area. The device performance of the TFTs fabricated with the excimer laser energy density of 230 mJ/cm 2 is almost equal for the single and double scanned area. This observation indicates that the overlapping laser irradiation with the laser energy density below 230 mJ/cm 2 does not change the characteristics of TFTs. Based on this result, we discuss the correlation between performance of active matrix organic light emitting display (AMOLED) panels and excimer laser energy density during ELA for SPC treated and non-treated poly-Si films.

X-ray resonant enhancement of the (200) crystallographically forbidden reflection in the inverse cubic spinel Co2MnO4 single crystal is presented. Anisotropic X-ray scattering results near the K absorption edges of both Co and Mn ions observed in the azimuthal angle dependence are interpreted with the anisotropic tensorial character of the X-ray susceptibility. Spectra calculations including the various electric multipole transition channels, such as dipole-dipole (E1-E1), dipole-quadrupole (E1-E2), and quadrupole-quadrupole (E2-E2), in two different polarization states of σ − σ and σ − π are discussed and compared with the experimental data to determine the channel of major contribution in the resonant scattering intensity.

Epitaxial Co2MnO4 thin films were grown on Nb(0.1wt.)-doped SrTiO3 single-crystal substrates with (100) and (110) crystal orientations by using pulsed laser deposition. Their crystal structures and magnetic properties were investigated. Both samples exhibited ferrimagnetic transitions with enhanced transition temperatures. Isotropic M-H loops were observed on the in-plane surface of Co2MnO4(00l) grown on Nb(0.1wt)-doped SrTiO3(100). Strong magnetic anisotropy was observed on the in-plane surface for Co2MnO4(ll0) grown on Nb(0.1wt)-doped SrTiO3(110). A magnetic easy axis existed along the elongated tetragonal direction. This was attributed to the strong interplay between the spin and lattice degrees of freedom in the Co2MnO4 thin film.

We grew epitaxial CoMn2O4 and Co2MnO4 thin films on Nbdoped (0.1 wt.%) SrTiO3(100) singlecrystal substrates by using pulsed laser deposition and studied how the growth temperature affected their crystal structures and surface morphologies. For Co2MnO4, increasing the growth temperature induced no significant changes except for an enlarged grain size. In contrast for CoMn2O4, increasing the growth temperature caused its surface morphology to evolve from spherical grains to rectangular nanorods; additionally, X-ray diffraction showed that these rectangular nanorod grains scattered to domains with different crystal orientations. We attribute this rectangular nanorod pattern to self-assembled domains originating from Jahn-Teller distortions and film-substrate lattice mismatch

Electronic and magnetic structures of a polycrystalline Sr2FeMoO6 double-perovskite have been studied by employing neutron powder diffraction (NPD) and X-ray spectroscopy. The Fe 2p edge X-ray absorption spectroscopy (XAS) clearly exhibits Fe2+-Fe3 + mixed valence states. Small but considerable local spin magnetic moments at Mo sites were observed in both neutron scattering and site-specific X-ray magnetic circular dichroism (XMCD) measurements. The mixed valence states by XAS and consistently observed nonnegligible magnetic moment by NPD and XMCD confirm the electronic and magnetic structures of Sr2FeMoO6 which have been controversial thus far.

We have fabricated two kinds of thin film transistors (TFTs) on the glass substrates using polycrystalline silicon (poly-Si) thin films with small and large grain sizes processed by Excimer Laser Annealing (ELA) and carried out a comparative analysis. The grain size was controlled by nickel atom content in amorphous silicon (a-Si) thin films. With increasing grain size of poly-Si thin films, the carrier mobility increased from 40.8 to 54.4 cm2/V s and the absolute value of threshold voltage reduced from 2.1 to 1.5 V. The observed improvements in the electrical characteristics of poly-Si TFTs are attributed mainly to the reduction of defect density rendered by large grain size. These observations indicate that the sputtered nickel atom content in a-Si layer is a key parameter in determining the characteristics of ELA processed TFTs fabricated on the glass substrates.

We successfully grew epitaxial CoMn2O4 thin films on Nb(0.1wt)-doped SrTiO3(001) single crystal substrates for the first time using the pulsed laser deposition technique and studied growth temperature dependencies of their structural and magnetic properties. Interestingly, the crystal orientation of the films depends on the growth temperature. At temperature below 870 °C, the surface normal direction of the film is the (400) direction with strained or relaxed domains whereas it changes to the direction (004) at 920 °C. M-T curves show features of ferrimagnetic spin order for all samples while the shapes of the M-T curves and M-H loops strongly depend on the growth temperature. These alterations of the magnetic properties with changing growth temperature are attributed to the changes in the crystal orientation of the CoMn2O4 thin films.

We grew highly epitaxial DyMn2O5 (DMO) thin films on Nb-doped TiO2(110) single crystal substrates by using the pulsed laser deposition technique and studied their magnetic properties. The surface normal crystal direction changed from DMO(002) to DMO(211) with increasing growth temperature from 750 °C to 950 °C. Bulk-like magnetic properties were observed for the film grown at 950 °C while behaviors different from the bulk were observed for the film grown at 750 °C. This difference in the magnetic properties is attributed to a structural deformation caused by the strain due to the substrate.

Active matrix organic light-emitting diode (AMOLED) displays are fabricated from polycrystalline silicon, which is formed in the single and double (overlap) scanned area during the excimer laser annealing (ELA) process. A redundant pixel line (RPL) design is proposed to remove the overlapping mura and, as a result, a 5-in AMOLED display is successfully fabricated without any non-uniform line image on the overlapping scanned area. This result indicates that the fabrication of a large-sized AMOLED panel is possible using ELA crystallization through an RPL design.

We have measured biomagnetic signals in rat by using a high-TC SQUID magnetometer system employing a small magnetically shielded box. For the rat cardiac magnetic field measurements, a healthy rat with body weight of about 350 g was anesthetized and fixed on a plastic xyz-stage in supine position inside the magnetically shielded box. We could obtain strong R-peak amplitude up to 56 pT with well defined P-, QRS-, T-wave, and ST-segment separating T-wave from QRS complex. We measured and analysed rat MCG waveforms for 5 × 5 grid measurements covering 60 mm × 60 mm area and 12 circular measurements centered at the heart position. This work demonstrates that the potential advantages of high-TC SQUID magnetometer system in evaluating the rat MCG measurement for animal models of cardiac electrical activities.

We examine the surface diffusion process of adatomic clusters on a (001)-oriented SrTiO3 single crystal using reflection high energy electron diffraction (RHEED). We find that the recovery curve of the RHEED intensity acquired after a homoepitaxial half-layer growth can be accurately fit into a double exponential function, indicating the existence of two dominant relaxation mechanisms. The characteristic relaxation times at selected growth temperatures are investigated to determine the diffusion activation barriers of 0.67 eV and 0.91 eV, respectively. The Monte Carlo simulation of the cluster hopping model suggests that the decrease in the number of dimeric and trimeric clusters during surface diffusion is the origin of the observed relaxation phenomena.

We studied the electrical conduction in the LaAlO3/SrTiO3 (LAO/STO) interface electron system with a sub-critical LAO layer thickness of ∼3.5 unit cells (uc). It was found that the true dividing point between metallic and insulating behaviour without gating lies near the LAO thickness of 3.5 uc. Our marginally metallic 3.5 uc sample showed a sharp transition to insulating state at temperatures which strongly depended on the applied negative back-gate voltage. The superior gate-controllability of the sample was attributed to its sheet carrier density which was an order of magnitude lower than those of conducting LAO/STO samples with 4 uc or more of LAO layers. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We have successfully fabricated a novel 3-D vertically stacked complementary metal-oxide-semiconductor hybrid inverter using a lower p-type poly-Si thin-film transistor (TFT) and an upper n-type amorphous Ga-In-Zn-O (a-GIZO) TFT. The device was fabricated step by step, starting from the fabrication of the lower poly-Si TFT via a high-temperature process to the fabrication of the upper a-GIZO TFT via a low-temperature process; this was done to prevent damage to the TFTs and to optimize their characteristics. The entire process was further simplified by the coplane gate structure that allows successive formation of the a-GIZO TFT on the poly-Si TFT. The transfer characteristics show clear inverter actions, indicating high performances of the TFTs.

Complex oxide systems have attracted considerable attention because of their fascinating properties, including the magnetic ordering at the conducting interface between two band insulators, such as LaAlO3 and SrTiO3. However, the manipulation of the spin degree of freedom at the LaAlO3/SrTiO3 heterointerface has remained elusive. Here, we have fabricated hybrid magnetic tunnel junctions consisting of Co and LaAlO3/SrTiO3 ferromagnets with the insertion of a Ti layer in between, which clearly exhibit magnetic switching and the tunnelling magnetoresistance effect below 10 K. The magnitude and sign of the tunnelling magnetoresistance are strongly dependent on the direction of the rotational magnetic field parallel to the LaAlO3/SrTiO3 plane, which is attributed to a strong Rashba-type spin-orbit coupling in the LaAlO3/SrTiO3 heterostructure. Our study provides a further support for the existence of the macroscopic ferromagnetism at LaAlO3/SrTiO3 heterointerfaces and opens a novel route to realize interfacial spintronics devices., The interface between two insulating oxides can play host to magnetic ordering. Here, the authors manipulate the spin transport in a hybrid magnetic tunnel junction comprising two ferromagnets: one a cobalt layer and the other the interface between lanthanum aluminate and strontium titanate.

We synthesized Bi2Sr2CaCu2O8+δ (Bi-2212) thin films with incorporated CaIrO3 (Ca-iridate) nanoparticles, by using pulsed laser deposition and post-growth ex situ annealing. We found that the density of incorporated Ca-iridate strongly affected the superconducting properties and microstructure of the Bi-2212 thin films. Incorporating a low density of Ca-iridate (450 laser pulses) in the Bi-2212 improved its superconducting properties (Tc-onset = 97 K, Tc-zero = 84 K) over those of pure Bi-2212 (Tc-onset = 94 K, Tc-zero = 80 K). However, incorporating a higher density (1800 pulses) significantly reduced Tc-zero to ≈ 57 K. Incorporating a low density of Ca-iridate also decreased the c-axis lattice constant. Films with incorporated Ca-iridate exhibited greater critical current density, Jc(B), than the pure Bi-2212 film. These results indicate that incorporating low densities of Ca-iridate nanoparticles into Bi-2212 can improve its superconducting properties.

Thin films of perovskite manganite La$_{0.7}$Ca$_{0.3}$MnO$_{3}$ were grown epitaxially on various substrates by either the pulsed laser deposition method or laser molecular beam epitaxy. The substrates change both the volume and symmetry of the unit cell of the films. It is revealed that the symmetry as well as the volume of the unit cell have strong influence on the metal-insulator transition temperature and the size of magnetoresistance., Comment: 6 pages, 3 figures

We report the fabrication and electrical measurements for LaAlO3/SrTiO3 (LAO/STO) heterostructures having various lateral sizes. When the sample size is reduced to the sub-micrometer range, the magnetoconductance (MC) curve deviates from classical parabolic behavior. Instead, a negative MC behavior appears with superimposed conductance fluctuations, which is attributed to weak antilocalization and universal conductance fluctuations. Using the Maekawa–Fukuyama model, the spin–orbit scattering and phase coherence lengths are estimated from the MC data, which are dependent on the gate voltage and temperature. Our comprehensive study shows that LAO/STO heterointerfaces provide a useful platform to explore quantum coherent transport of strongly correlated electrons.

The use of an inline furnace has been evaluated for solid phase crystallisation (SPC) of amorphous silicon films to improve throughput without sacrificing thin-film transistor performance. An attempt was made to develop the SPC process at temperatures of 700°C without causing any glass distortion. The characteristics of a fabricated p-channel active material exhibited a field effect mobility of 16.9 cm2/Vs, a threshold voltage of −4.6 V and a subthreshold swing of 0.9 V/dec.

This article conducted a comparative analysis on thin film transistors (TFTs) fabricated by using the excimer laser annealed (ELA) polycrystalline silicon (poly-Si) and those fabricated by using the Ni-sputtered ELA poly-Si. The grain size of the Ni-sputtered ELA poly-Si is 3 times greater than that of the ELA poly-Si. The Ni-sputtered ELA poly-Si TFTs showed a higher drain current, lower threshold voltage, smaller subthreshold swing, and higher electron mobility than the ELA poly-Si TFTs. This improvement is attributed mainly to the reduction of the defect density rendered by the large grain size.