INCOMMENSURABLE AND GLASSY BEHAVIOR OF CD2NB2O7 OXIDE PYROCHLORE SINGLE-CRYSTALS

被引:9
作者
KOLPAKOVA, NN
HILCZER, B
WIESNER, M
机构
[1] POLISH ACAD SCI,INST MOLEC PHYS,PL-60179 POZNAN,POLAND
[2] ADAM MICKIEWICZ UNIV POZNAN,INST PHYS,PL-60780 POZNAN,POLAND
关键词
PHASE TRANSITIONS; INCOMMENSURATE PHASE; GLASSY STATE; DIELECTRIC DISPERSION; OXIDE PYROCHLORE;
D O I
10.1080/01411599408200341
中图分类号
O7 [晶体学];
学科分类号
0702 ; 070205 ; 0703 ; 080501 ;
摘要
Low-frequency studies of the complex dielectric permittivity of Cd2Nb2O7 single crystals in the temperature range of 4-80 K are reported. Above T-com similar or equal to 46 K an anomalous thermal hysteresis of epsilon' over the frequency range of 10 kHz-2 MHz as well as dielectric relaxation may be related to the existence of discommensurations and their dynamics. In the vicinity of T-f similar or equal to 18 K the temperature and frequency behavior of epsilon* is typical of orientational glasses. Two relaxation process fitted with the Vogel-Fulcher law and the Arrhenius law take place near T-f. The first process is related to frustration in displacements of the ''seventh'' oxygens relative to Cd2+ ions and is characterized by freezing in of Cd-0(7) orientations below T-0 similar or equal to 7 K. The Arrhenius-type process is related to relaxation of ferroelastic and ferroelectric domain walls.
引用
收藏
页码:113 / 124
页数:12
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