Classical ferroelectriclike behavior of highly orderedPb(Sc1/2Nb1/2

Abstract

The ferroelectric phase transition behavior in the highly ordered Pb(Sc 1/2 Nb 1/2 )O 3 has been investigated by the dielectric and Brillouin spectroscopy. The dielectric permittivity ε r exhibits a sharp maximum without any frequency dispersion at its Curie temperature T c . In the temperature range far above T c , it was noted that the dielectric permittivity exhibits a noticeable deviation from the Curie-Weiss law below the characteristic intermediate temperature T * = 500 K, which is common to most of the Pb-based oxide perovskite relaxors. Upon cooling, the frequency of the longitudinal acoustic phonon mode exhibits a remarkable softening towards T c . The relaxation time of the order parameter calculated using the Landau-Khalatnikov approach was determined to be more than one order of magnitude lower than that of the disordered Pb(Sc 1/2 Nb 1/2 )O 3 and is very close to that observed in the paraelectric phase of the classical ferroelectric, BaTiO 3 . The observed dielectric and relaxation features are qualitatively discussed in terms of the difference in the strength of the random electric fields.

Acoustic phonon dynamics of Pb(Sc1/2Ta1/2)O3ceramics studied by Brillouin scattering spectroscopy

“…( 2). Such a critical slowing down for the order-disorder nature was reported for highly-ordered PSN 33) and BT single crystal. 34) For the paraelectric phase above T c , we obtained T 0 = 207 K and τ 0 = 0.33 ps, and for the ferroelectric phase, T 0 = 352 K and τ 0 = 0.19 ps.…”

Evidence for cluster spin glass phase with precursor short-range antiferromagnetic correlations in the B -site disordered Ca(Fe1/2Kumar1, Senyshyn2, Pandey3 2019Phys. Rev. B417210View full textAdd to dashboardCite

“…One of the unique features of such complex perovskites is that the ratio of A : A or /B : B is fixed like 1 : 1, 1 : 2, and 1 : 3, akin to compounds obeying normal valence rules but unlike the solid-solution systems. However, the nature of their occupancy at the A or B site of ABO 3 perovskite lattice varies all the way from nearly ordered [9] to nearly disordered [10] depending on the compounds, and sometimes in the same compound also as a result of long-term annealing [10]. Within the broad family of such site-and charge-disordered/ordered compounds, complex perovskites with the formula A(B 1/2 B 1/2 )O 3 , where B : B are in 1 : 1 ratio, commonly known as double perovskites, have received immense attention from the point of view of the colossal magnetoresistance [11][12][13], half metallicity [14][15][16], metal to insulator transition [17][18][19], superconductivity [20,21], etc.…”

“…Within the broad family of such site-and charge-disordered/ordered compounds, complex perovskites with the formula A(B 1/2 B 1/2 )O 3 , where B : B are in 1 : 1 ratio, commonly known as double perovskites, have received immense attention from the point of view of the colossal magnetoresistance [11][12][13], half metallicity [14][15][16], metal to insulator transition [17][18][19], superconductivity [20,21], etc. ), normal ferroelectricity [9] and relaxor ferroelectricity [4][5][6][22][23][24], long-range magnetic ordering [25][26][27][28][29][30][31], and multiferroicity [32][33][34][35]. Multiferroicity in the double perovskites of the type A(B 1/2 B 1/2 )O 3 with A = Pb, Ba, Sr, Ca can be * dp.mst1979@gmail.com easily introduced by choosing one of the B-site cations with partially filled d orbitals (d n ) imparting magnetic properties (e.g., Cr, Mn, Fe, Co, Ni, Ru, Re, Os, Ir) and the other with unfilled d orbitals (d 0 ) (e.g., Nb, Sb, Ta, W, Mo) required for inducing ferroelectric distortion [36], as was first demonstrated by Russian scientists who synthesized these complex multiferroic perovskites nearly six decades back [37][38][39].…”

Anomalies of Brillouin Light Scattering in Selected Perovskite Relaxor Ferroelectric Crystals

“…Both in PMN and PMT, the relaxation time of PNRs showed a characteristic slowing behavior with a marked anomaly below T f . The anomalous behavior of acoustic phonons and the central peak has been studied extensively in various Pb-based relaxor systems by Brillouin light scattering spectroscopy [ 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 ]. A significant softening of LA and TA phonon modes accompanied by a broad central peak was observed below T * in PZN-0.045PT and PZN-0.09PT [ 44 ].…”

“…In 0.65PIN-0.35PT, anomalous behavior of the LA phonon mode at the cubic–tetragonal structural phase transition and two-component central peaks were studied using Brillouin light scattering spectroscopy [ 50 ]. The width of the LA phonon showed Landau–Khalatnikov-type behavior in the vicinity of the structural phase transition in a highly ordered PSN [ 52 ]. This review focuses on the Brillouin light scattering studies of dynamical aspects of PNRs in some selected RFEs carried out by the authors in the past.…”