DAU Library

학위논문 동서

KNbO3 단결정의 전기적 특성에 관한 연구

김선주

부산: 동아대학교 1994. -

44장: 삽도; 27cm. -

학위논문(석사)- 동아대학교 교육대학원 물리교육전공 94년6월

영문초록 : I have grown K (Nb_(l-x)V_(x))O_(3) [x=0, 0.005, 0.01, 0.11] single crystals by Czochraski method : the melt of compound constitutents are more aboundant than (Nb_(l-x)V_(x))O_(3) [x = 0, 0.005, 0.01, 0.1] molecules. X-ray diffraction of K(Nb_(l-x)V_(x))O_(3) [x=0, 0.005, 0.01, 0.1] reveals that they belong to the orthorhombic group at the room temperature. V^(5+) ion substitution does not effect the structure of the crystals. KNbO_(3) single crystal grown from the 0.5 K_(2)CO_(3)+0.5 Nb_(2)CO_(5) melt shown a larger thermal hysteresis curve at the first transition temperature than a KNbO_(3) single crystal grown from 0.58 K_(2)CO_(3)+0.42 Nb_(2)CO_(5) melt. The Curie temperature of the latter is 2.5 ℃ higher than the former. Dielectric constant of both crystals increases, as a function of the frequency in the 1MHz-6MHz range. As I substitute V^(5+) ions more, dielectric constant increases, and the second phase transition temperature and the Curie temperature more to higher temperatures. A.C. conductivity of K(Nb_(l-x)V_(x))O_(3) is measured : it depends on the temperature and the frequency, and increases as more V^(5+) ions are substituted in the crystal. Temperature dependence of the conductivity below 10^(6) Hz can be interpreted as a hopping conduction by charged particles (CBH), and that over 10^(7) Hz which is independent of temperature and proportional to ω^(2) can be explained as a hopping conditions among impurities.

바로가기