Published: Theoretical Analysis of Nanogenerators with Nanorods for Piezoelectric Energy Harvesting

Our paper entitled “Theoretical Analysis of Nanogenerators with Aligned Nanorods for Piezoelectric Energy Harvesting” has been published in Sens. Mater. We theoretically analyzed nanogenerators with aligned piezoelectric nanorods. It was shown that for the same piezoelectric materials, using a rod-shaped unit will increase the piezoelectric constant d33 by 33% compared with using a film, owing to less substrate clamping. In addition, for the case of applying normal force, the aligned nanorod array can generate an output power one or more orders of magnitude higher than films within the same volume. This sort of nanogenerator will play an important role in the integration with miniaturized sensors in the off-resonant mode.

Citation: Sens. Mater. 31, 3669-3679 (2019).

Published: Large impact of strain on electro-optic effect in (Ba, Sr)TiO3 films: experiment and theoretical comparison

Our paper entitled “Large Impact of Strain on the Electro-optic Effect in (Ba, Sr)TiO3 Thin Films: Experiment and Theoretical Comparison” has been published in Appl. Phys. Lett. We experimentally clarified that the EO properties of compressively strained BST thin films are enhanced toward the phase transition temperature modified by the strain. Although the measured EO coefficient rc was less than that theoretically predicted, the experimentally observed strain effect on the EO properties is in good qualitative agreement.

This paper was was selected as a featured article.

Citation: Appl. Phys. Lett. 115, 092901 (2019).

Published: Theoretical model of electro-optic effect in strained c-domain (Ba, Sr)TiO3 films

Our paper entitled “Theoretical Estimation of the Linear Electro-optic Effect in Compressively Strained c-domain (Ba, Sr)TiO3 Thin Films using a Phenomenological Thermodynamic Model” has been published in J. Ceram. Soc. Jpn. To estimate the EO coefficients, we considered not only the intrinsic EO effect but also the elasto-optic effect by converse piezoelectric response. We found that the EOresponse is mostly determined by the difference in temperature from the ferroelectric-to-paraelectric phase transition boundary modified by the strain.

Citation: J. Ceram. Soc. Jpn. 127, 348-352 (2019).

Awarded: Shinya KONDO

Shinya KONDO won the presentation award of The 38th Electronics Division Meeting of the Ceramic Society of Japan held in Kawasaki, Japan for his presentation on the electro-optic effect in c-domain (Ba, Sr)TiO3 thin films.

Published: Significant effect of Mg-pressure-controlled annealing for Sb-doped Mg2Si

Our paper entitled “Significant Effect of Mg-pressure-controlled Annealing: Non-stoichiometry and Thermoelectric Properties of Mg2-δSi1-xSbx” has been published in Phys. Chem. Chem. Phys. Non-stoichiometry of Mg2−δSi1−xSbxcontrolled via Mg-pressure-controlled annealing has significant influence on the carrier concentration and other thermoelectric properties.

Citation: Phys. Chem. Chem. Phys. 20, 25939-25950 (2018).

Awarded: Shinya KONDO

Shinya KONDO won Poster Award of The 10th China-Japan Symposium on Ferroelectric Materials and Their Applications (JCFMA10) held in Inuyama, Japan for his poster “Temperature and Strain Dependences of Electro-optic Effect in c-domain (Ba, Sr)TiO3 Thin Films Fabricated by Pulsed Laser Deposition”.

Published: 2D-epitaxial growth of BST on MgO using a SrTiO3/TiO buffer layer

Our paper entitled “Strong Impact of SrTiO3/TiO2 Buffer Layer on Epitaxial Growth and Dielectric Response of Ba0.7Sr0.3TiO3 Thin Films on MgO” has been published in Jpn. J. Appl. Phys. 270-nm-thick (001)-epitaxial BST films were deposited by pulsed laser deposition on STO/TiO2-buffered MgO with a SrRuO3 bottom electrode. It was found that the insertion of SrTiO3/TiO2 buffer layer enabled a two-dimensional growth of BST film, which resulted in the out-of-plane dielectric constant exceeding 1000.

Citation: Jpn. J. Appl. Phys. 57, 0902B1 (2018).