Light-induced intrinsic defects in PLZT ceramics

Divalent impurity ion defects in potassium tantalate: EPR investigations

“…The observation of the Co 2+ (2) centre in KTaO 3 is an important contribution concerning the models of divalent impurity ion defects in this host matrix. Different samples have been studied, showing different ratios between the EPR signal intensities of the centres of types (1) and (2). It seems that the conditions of crystal growth and/or the different subsequent treatments have a strong influence on the distribution of the defect types, as also evidenced by the high temperature EPR measurements of Cu 2+ centres.…”

“…(2) centres in the range of 300 -1000 K has been studied. The EPR spectra for 300 K and 900 K are shown in Fig.…”

“…Trivalent ions like Fe 3+ can occupy different sites replacing both Ta 5+ ions with or without an adjacent oxygen vacancy [1] and K + ions with adjacent interstitial oxygen [2]. Divalent impurities like Cu 2+ ions substitute for Ta 5+ sites only, to our knowledge from our investigations and from literature.…”

The effects of applied electric fields on the EPR spectra of Fe3+ ion in tetragonal SrTiO3 crystal

“…However, in a few cubic paramagnetic systems, e.g., Co 2+ or Mn 2+ in SrCl 2 [3,4] and Fe 3+ at Ta 5+ site of KTaO 3 [5], the large electric-fieldinduced zero-field splittings were observed. These electric-field-effects are attributed mainly to the electric-field-induced displacements of paramagnetic ions along the electric-field direction because of the loose binding between the paramagnetic impurity and the lattice and/or the large local electric field at the sites of paramagnetic ions [3][4][5][6]. For the noncubic system with inversion symmetry, similar study is fewer.…”

Growth and characterization of barium-doped potassium tantalate crystals

“…One possible way of overcoming this problem, while still having the excellent lattice matching between the KNTN film and the KT substrate is by doping the KT with a heterovalent ion. To increase the electrical conductivity of KT several authors have tried different dopants [3][4][5][6][7][8].…”