Electrical studies on Zr-modified Bi_3.25La_0.75Ti₃O₁₂: a promising FRAM ceramic

Abstract

Zr-modified Auruvillius family of lanthanum bismuth titanate, namely Bi 3.25 La 0.75 Ti 3¡x Zr x O 12 (BLTZ, x D 0, 0.1, 0.3, 0.5, 0.7 and 1), was prepared by solid-state reaction method. Dielectric properties of the ceramics were studied as a function of temperature. Hysteresis measurements were also performed. Among the composition, Bi 3.25 La 0.75 Ti 2.9 Zr 0.1 O 12 (BLTZ1) showed large remnant polarization compared to the promising ceramic, namely Bi 3.25 La 0.75 Ti 3 O 12 . The results were corroborated with the pyroelectric, electric polarization and Raman spectroscopic data.

Improving the Electrical Properties of Zr-Doped Bi3.15Nd0.85Ti3O12 Thin Films by Engineering Polarization Rotation

“…For x = 0.3 and 0.5, the position of the diffraction peak shifts toward low 2h value after Zr 4+ doping, demonstrating that the lattice parameter of BIT thin films is enlarged after Zr 4+ doping. Our observation agrees with that of Reddy et al 11 In addition, the c/a ratio increased with doping level up to x = 0.1, but decreased on further Zr 4+ doping; this trend is the same as that for the degree of (117) orientation. The increase in c/ a ratio facilitates (117) orientation because it is closer to the c-axis than the a-axis.…”

“…The decrease in lattice parameter a for x = 0.05, 0.1, and 0.3, compared with the parent compound, is attributed to the structural constraint induced by the (Bi 2 O 2 ) 2+ interlayer; the interlayer does not allow the crystal lattice to shrink on Zr 4+ modification. 11 With increasing Zr 4+ doping content, this interlayer constraint will not longer be effective; moreover, the c-parameter is found to be higher for all compounds compared with BNT. This result is consistent with tetragonal strain (c/a).…”

“…Zr 4+ ions have been used to substitute at Ti sites to enhance the electrical properties of such films. Some studies [9][10][11][12][13][14][15] demonstrated that Zr-doped BIT thin films show enhanced polarization owing to the change in lattice parameter. Moreover, growth along the c-axis is relatively easy for epitaxial BIT films, 16 which exhibit negligible polarization.…”

Impedance Spectroscopic Studies on Zr-Modified BI3.25LA0.75TI3O12 Ceramics

“…Finally the powder was pressed into circular shaped pellets using PVA as binder, and sintered at 1050 o C for 4-5 hours for higher densification. The singlephase formation of crystalline structure was confirmed by the X-ray diffractogram recorded by a Pan Analytical Philips X'pert plus difractometer with Cu KÅ radiation and the data was reported in our earlier paper [6].…”

“…Since the ionic radius of Zr 4+ is about 18% larger than that of Ti 4+ , therefore the substitution of 'Zr ' could enhance the relative ionic displacement, which might result into large P r (remnant polarization) value, compared to lanthanum bismuth titanate. Keeping this view, an attempt was made in our earlier investigation [6]. An interesting and striking feature of our earlier result is that the compound with Zr content with 0.1 concentration was showed the higher Pr value.…”