http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Yukikuni Akishige (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
-
Phase Transition of New Ferroelectric BaTi2O5
Yukikuni Akishige,Akane Kitahara,Hirotake Shigematsu,Isao Takahashi 한국물리학회 2005 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.46 No.1
The dielectric constant and dielectric loss tangent (tan) of a new ferroelectric BaTi2O5 were measured in a temperature range of 300 - 860 K. The along the b-axis of the crystal, grown in air, shows a sharp dielectric anomaly, reaching 25,000 at a ferroelectric Curie temperature of TC = 752 K. XRD patterns of the pulverized single crystals were measured in the temperature range of 300-1000 K; the thermal expansion coecients of lattice parameters were estimated. Tiny jumpswere observed in the lattice constant vs. T curves around TC by a/a = 0.10 %, b/b = 0.11 %,and c/c = 0.13 %. X-ray diraction measurements for the single crystal were carried out at room temperature and at 773 K by using a spherical sample. The results revealed atomic displacements responsible for the ferroelectricity of BaTi2O5.
-
Successive Phase Transition of (Sr1?xBax)2Nb2O7
Yukikuni Akishige,Katsuhiro Fukano,Misako Kamata 한국물리학회 2003 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.42 No.IV
Sr2Nb2O7 is one of the high-TC ferroelectrics with a perovskite slab structure. We attempted crystal growth of the pure and Ba doped Sr2Nb2O7, and investigated some thermal and electrical properties of the crystals. For the single crystal with x = 0, the specic heat Cp and the dielectric constant, 0b - j00 b , along the b-axis (perpendicular to the cleavage plane) were measured from 5 K to 600 K and from 10 K to 900 K, respectively. An excess Cp was observed associated with the incommensurate phase transition: it begins at 350 K and shows a like anomaly at TINC = 495 K. The 0b shows an in ection and a thermal hysteresis at around TQC 330 K in addition to a large dielectric anomaly at TLOW = 97 K. Above 400 K, a low frequency dielectric dispersion mainly due to ionic conduction takes place. As for Ba doped crystals, the ferroelectric phase transition at TLOW disappears and a new ferroic phase transition appeas at 465 K.
-
Raman Scattering Study on New Ferroelectric BaTi2O5 Single Crystals
Anwar Hushur,Hirotake Shigematsu,Seiji Kojima,Yukikuni Akishige 한국물리학회 2005 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.46 No.1
A new ferroelectric single crystal was studied by using Raman scattering in a wide temperature range from 26 to 560 C. In addition to normal Raman modes determined by selection rules for space group C2 symmetry, a strong central component was observed. Upon heating, a central peak appears around 300 C. The lowest mode at 80.5 cm1 at room temperature does not show clear softening, and broadening occurs approaching Tc and then disappears. Above Tc, the number of Raman modes decreases markedly in relation to the ferroelectric phase transition. Another two strong bands observed at 344 cm1 and 589 cm1 show a remarkable change upon heating. These are correlated with the order-disorder nature of this ferroelectric phase transition.
-
Heat capacity, X-ray scattering and neutron scattering studies in Rb2SeO4
Hirotake Shigematsu,Hiroyuki Mashiyama,Hitoshi Kawaji,Takeo Tojo,Tooru Atake,Yukikuni Akishige 한국물리학회 2005 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.46 No.1
The structural phase transition and behavior of the 2 3 phonon branch of Rb2SeO4 have been investigated with the use of heat capacity measurement and X-ray and neutron scattering technique. No phase transition was detected down to 2 K, both in thermal analysis and in neutron elastic scattering. However, neutron inelastic scattering showed a slight softening of the phonon excitation frequency below 100 K. Two typical trst-order-type anomalies due to the phase I - phase II transition and melting were observed at 821 K and 1233 K, respectively. The entropy change for the phase I - phase II transition was determined as 12.46 Jmol1K1.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
