Does Highly Dilute KTaO₃:Li Undergo Collective Glassy Freezing?

Raman and impedance spectroscopy methods of P 2 O 5 –Li 2 O–Al 2 O 3 glass system doped with MgO

“…For all compositions, a slight degree of decentralization can be detected at impedance. The semicircular arcs are depressed and their centers lie below the (Z′) axis, which suggests that the relaxation is of non-Debye type in all the cases [28,29]. The deviation from a Debye profile in the present system may be attributed to the formation of the nanopolar clusters [28].…”

Evidence of polar nanoregions in quantum paraelectric KTaO3

“…However, real crystals always contain different kinds of imperfections that provoke incomplete compensation of the elementary dipoles and consequently the sample bears a nonzero net polarization. The second harmonic polarization response is basically due to the asymmetry in the potential well [26]. It has recently been shown [27][28][29] and form polar clusters.…”

“…Recently Tyunina et al [6] have reported strain-induced ferroelectric order in epitaxial thin film KTaO 3 . Doping KTaO 3 with Li þ ions, K 1À x Li x TaO 3 , causes a very complex polar behavior [1,[7][8][9][10][11][12][13][14][15][16][17][18]. In the case of x 4x cr % 0:02, [8,11], a ferroelectric state appears.…”

“…At x ox cr a relaxor or glass-like behavior is realized. A large interest is attracted by a very dilute system with a low concentration x o0:01 [15,16]. Because of the high polarizability of the KTaO 3 host lattice with the soft TO 1 transverse optic mode, polar impurities and defects, can strongly influence on physical properties and formation of the polar nanodomains is possible.…”

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

“…According to the suggestion made by us [1] the substitution of K + ions by off-center Li + in KTaO 3 is considered as the source of induced polar clusters of short range order at low temperatures for this crystal. The low-temperature state of KLT-0.18 may be considered as a quantum superparaelectric one that may be toggled into an improper ferroelectric while applying an electric field [2] or a chiral glass state [3]. …”