Spintronics device

Features

To realize ultralow-power and high-performance integrated circuit and information processing, spintronics physics, material, devices are studied.

Study on Phase Change Materials for PCRAM Application

Features

Phase change random access memory (PCRAM) has attracted attention as next-generation non-volatile memories. A conventional PCM is Ge-Sb-Te which shows a fast crystallization speed and an excellent reversibility of phase transition. However, Ge-Sb-Te has a low crystallization temperature of about 150 ºC and a high melting temperature of over 600 ºC , which limits data retention and causes high power consumption, respectively.
We have developed a new phase change materials with high crystallization temperature and low melting point such as Ge-Cu-Te etc, which have high potential as PCRAM materials with high thermal stability and low power consumption (Fig.1,2).

Targeted Application(s)/Industry

Our materials are developed for PCRAM, DVD recording materials etc. We hope the collaboration research with companies which are interested in our developed phase change materials.

Supercritical Hydrothermal Synthesis of Organic-Inorganic Hybrid Nanoparticles

Features

We invented supercritical hydrothermal synthesis method for the synthesis of organic modified nanoparticles (NPs). Under the supercritical state, the organic molecules and metal salt aqueous solutions are miscible and water molecule works as an acid/base catalyst for the reactions. Organic-inorganic conjugate NPs can be synthesized under this condition. This hybrid NPs show high affinity with the organic solvent or the polymer matrix, which leads to fabricate the organic inorganic hybrid nanomaterials with the trade-off function (super hybird nanomaterials). These hybrid materials of polymer and ceramics fabricated with NPs achieve both high thermal conductivity and easy thin film flexible fabrication, namely trade-off function.

Targeted Application(s)/Industry

For example, by the surface modification of BN particles by supercritical method, affinity of BN and polymers could be improved, so that high BN content of hybrid materials, thus high thermal conductivity materials, could be synthesized. Also by dispersing high refractive index NPs like TiO2 or ZrO2 into polymers transparently, we can tune the refractive index of the polymers. CeO2 nanoparticles are expected to be used for high performance catalysts. To transfer those supercritical fluid nano technologies, a consortium was launched with more than 70 companies.

Suppression of Intergranular Degradation of Polycrystalline Materials by Grain Boundary Engineering

Features

Intergranular degradation often results in decreased lifetime, reliability and economical efficiency of polycrystalline materials. In spite of persistent efforts to prevent such degradation, its complete suppression has not yet been achieved. Grain boundary studies have revealed that coincidence-site-lattice (CSL) boundaries have stronger resistance to intergranular degradations than random boundaries. The concept of ‘grain boundary design and control' has been refined as grain boundary engineering (GBE). GBEed materials which are characterized by high frequencies of CSL boundaries are resistant to intergranular degradations. Our group has achieved very high frequencies of CSL boundaries in commercial stainless steels by GBE. GBEed stainless steels showed significantly stronger resistance to intergranular corrosion (see Figs. 1 and 2), weld-decay, knife-line attack, stress corrosion cracking, liquid-metal embrittlement, radiation damage, etc. and much longer creep life (see Fig. 3) than the unGBEed ones.

Targeted Application(s)/Industry

By using this GBE processing, we expect to conduct effective collaborative research in related fields.

Synthesis and material characterization of new organic ferroelectric materials, molecular semiconductors, molecular magnets.

Features

Multifunctional molecular-assemblies and hybrid organic - inorganic materials are examined from the viewpoint of structural freedom of organic molecules. The spin and electronic states of molecular-assemblies are designed in terms of electrical conductivity, magnetism, and ferroelectricity. Diverse molecular assemblies from single crystal, plastic crystal, liquid crystal, gel, to Langmuir-Blodgett film are our research targets, which were hybridized with inorganic gigantic clusters and metal nanoparticles. We are prepared to provide academic consultations to companies interested in our research.

Synthesis of Novel Nano-Carbon Materials Using Nano-Space as a Reaction Field

Features

We are designing and developing novel nanocarbon materials together with their hybrids by controlling the reaction nano-fields for the syntheses of these materials. One example is fully tailored carbon nanotubes with uniform diameter and length. Another noteworthy material is zeolite-templated carbon which has structure regularity like zeolite and a surprisingly large surface area up to 4000 m2/g. In addition, we have recently developed a method for a complete coating of the entire surface of mesoporous silica with graphene layers.

Targeted Application(s)/Industry

We are trying to apply these unique nanomaterials to electronic device, electrochemical capacitors, lithium-ion batteries, hydrogen storage, biosensors and capsules for drug and gene delivery. We hope to conduct collaborative research with a willing company for a practical application of this technology in industry.