Zobrazeno 1 - 10
of 64
pro vyhledávání: '"Nishimatsu, Takeshi"'
Publikováno v:
J. Phys. Soc. Jpn. 85, 114714 (2016)
We present a semi-empirical effective Hamiltonian to capture effects of disorder associated with Ba and Sr cations occupying $A$ sites in (Ba$_{x}$Sr$_{1-x}$)TiO$_3$ on its ferroelectric phase transition. Averaging between the parameters of first-pri
Externí odkaz:
http://arxiv.org/abs/1608.06433
Publikováno v:
Phys. Rev. B 93, 054110 (2016)
We use molecular dynamics simulations for a first principles-based effective Hamiltonian to calculate two important quantities characterizing the electrocaloric effect in BaTiO$_3$, the adiabatic temperature change $\Delta T$ and the isothermal entro
Externí odkaz:
http://arxiv.org/abs/1506.00525
Autor:
Grünebohm, Anna, Nishimatsu, Takeshi
Publikováno v:
Phys. Rev. B 93, 134101 (2016)
We report modifications of the ferroelectric and electrocaloric properties of BaTiO$_3$ by defects. For this purpose, we have combined \textit{ab initio}-based molecular dynamics simulations with a simple model for defects. We find that different kin
Externí odkaz:
http://arxiv.org/abs/1502.05201
Publikováno v:
J. Phys. Soc. Jpn. 84, 024716 (2015)
A first-principles based effective Hamiltonian is used within a molecular dynamics simulation to study the elastocaloric effect in PbTiO3. It is found that the transition temperature is a linear function of uniaxial tensile stress. Negative temperatu
Externí odkaz:
http://arxiv.org/abs/1404.5459
Publikováno v:
J. Phys. Soc. Jpn. 82, 114605 (2013)
The electrocaloric effect (ECE) in BaTiO3 is simulated using two different first-principles based effective Hamiltonian molecular dynamics methods. The calculations are performed for a wide range of temperatures (30--900 K) and external electric fiel
Externí odkaz:
http://arxiv.org/abs/1307.7011
The perovskite crystal BaTiO3 is modeled using a first-principles based effective Hamiltonian and molecular dynamics simulations are performed to estimate the pyroelectric response. The electrocaloric temperature change, \DeltaT, is calculated for di
Externí odkaz:
http://arxiv.org/abs/1208.5829
Autor:
Aoyagi, Kenta, Nishimatsu, Takeshi, Kiguchi, Takanori, Konno, Toyohiko J., Kawazoe, Yoshiyuki, Funakubo, Hiroshi, Kumar, Anil, Waghmare, Umesh V.
We report observation of 90-degree ferroelectric domain structures in transmission electron microscopy (TEM) of epitaxially-grown films of PbTiO3. Using molecular dynamics (MD) simulations based on first-principles effective Hamiltonian of bulk PbTiO
Externí odkaz:
http://arxiv.org/abs/1202.3893
Autor:
Fu, Desheng, Fukamachi, Kouhei, Sakamoto, Naonori, Wakiya, Naoki, Suzuki, Hisao, Itoh, Mitsuru, Nishimatsu, Takeshi
We report that an energetic plasma process is extremely effective in enlarging the unit cell volume and ferroelectric distortion of the ferroelectric oxides, resulting in a significant increase in its Tc. We demonstrate experimentally that c-axis ori
Externí odkaz:
http://arxiv.org/abs/1102.4473
Publikováno v:
Phys. Rev. B 82, 134106 (2010)
Specific forms of the exchange correlation energy functionals in first-principles density functional theory-based calculations, such as the local density approximation (LDA) and generalized-gradient approximations (GGA), give rise to structural latti
Externí odkaz:
http://arxiv.org/abs/1007.1127
We use molecular dynamics simulations to understand the mechanisms of polarization switching in ferroelectric BaTiO$_3$ achieved with external electric field. For tetragonal and orthorhombic ferroelectric phases, we determine the switching paths, and
Externí odkaz:
http://arxiv.org/abs/0809.2951