Room temperature XRD patterns were recorded with an

2. Experimental
Relative permittivity measurements above room temperature were carried out with an Impedance/Gain Phase Analyser (model: 1260, Solartron Instruments, Farnborough, UK) coupled to EPZ-6438 tube furnace (model: MTF, Carbolite, Hope Valley, UK). Sub-ambient measurements were performed using an LCR meter (Agilent E4980A, Agilent, USA) in a closed-cycle He refrigerator (Oxford Instruments Ltd., Oxfordshire, UK). The sintered pellets were coated with Pt or Ag paste. Capacitance was measured versus temperature (from 300 to 520 K and from 10 to 300 K at 2 K intervals) at four different frequencies (1, 10, 100 and 1000 kHz). Sintered pellets were polished using SiC sandpaper and 6 and 1 μm diamond paste polishing pads, and subsequently thermally etched at 1200 °C for 30 min.
3. Results
3.1. Structure and purity
Fig. 1. (a) Room temperature XRD patterns for (1-x)BaTiO3-xBiGdO3 solid solutions (logarithmic scale): (1) x = 0.00, (2) x = 0.02, (3) x = 0.04, (4) x = 0.06, (5) x = 0.08, (6) x = 0.10, (7) x = 0.15 (* = Bi1.55Gd0.45O3 – PDF no. 00-048-0351). (b) Evolution of foraminifera (2 0 0)/(0 0 2) peak splitting with composition.Figure optionsDownload full-size imageDownload as PowerPoint slide