Low Temperature Dielectric Behavior in Iron Doped KTaO 3

K0.9982Li0.0018TaO3Crystal Under External DC Electric Field

“…The compare the influence of external electric field effects in temperature about 10 K, the dc electric field E = 8 kV/cm applied to the pure KTaO 3 crystal decreased the value of electric permittivity ε of about 40% in relation to the value of ε for the zero dc electric field (E = 0 kV/cm), while just the same relation for E = 20 kV/cm was 60%. For the iron doped crystals with concentrations 0.01% and 1% [15,16], there were observed the existence of polar clusters with short-range local order in both, were noticed the lowering of ε not more than 10% for E = 5 kV/cm. The demonstrated in this work results for KLT-0.18 crystal show much stronger influence of the dc electric field on the values of the real ε and imaginary ε part of electric permittivity, which ε decreased 60% under the influence of the dc electric field E = 5 kV/cm.…”

“…The results, obtained by us, for the K 1-x Li x TaO 3 x = 0.0018 crystal (KLT-0.18) on dc electric field are very interesting in compared with issues for pure KTaO 3 crystal and the iron doped KTaO 3 crystals under external electric field [15,16,29]. The compare the influence of external electric field effects in temperature about 10 K, the dc electric field E = 8 kV/cm applied to the pure KTaO 3 crystal decreased the value of electric permittivity ε of about 40% in relation to the value of ε for the zero dc electric field (E = 0 kV/cm), while just the same relation for E = 20 kV/cm was 60%.…”

“…It is possible, that the small amount of dopant (Li + or Nb + ) or intrinsic imperfection of the crystal through elastic interactions can lead to local glass-like short-range order or even ferroelectric long-range order. The low temperature properties of doped crystals result from the dipole moment given by the off-center position of dopant ions [1][2][3][15][16][17][18][19][20][21][22][23][24][25][26][27].…”

The Local Order in KTaO3Admixtured by the Ions of Li+

“…Therefore, by testing the properties of this crystal, the elastic coupling should be taken into consideration through which the induced dipole moments can interact, even in the small concentration of the admixture. Hence, alike to the tested crystals KTaO 3 : Fe with x = 0.01% and x = 1% [12,13], the appearance of a coexistence of polar clusters is possible, in the area of which the short-range order with the paraelectric phase is realized. This phase is called the improper glass.…”

“…In the small amount of the admixture (x < 0.022) the induced electric dipole interacts with each other by the elasticity coupling. This coupling leads to the local electric order [12][13][14][15][16][17][18][19].…”