1：Experimental Design and Method Selection:

The samples were prepared by conventional solid state and mechanochemical technique from fine powders of metal oxides or metal carbonates. The nominal purity of the initial powders, as well as their manufacturers are given in Table

2：Sample Selection and Data Sources:

Analytical grade high-purity (

3：9%) oxide precursors, BaCO3, ZrO2, TiO2 and SnO2 were used. List of Experimental Equipment and Materials:

X-ray diffractometer with monochromatic Cu-Kα radiation (λ=

4：54178 ?) under 40 kV/30 mA, Electronic Densimeter MD-3005 ALFA MIRAGE, field-emission scanning electron microscopy (FE-SEM) (JEOL 7600F) operated at 15 kV, Precision LC material analyzer (Radiant, U.S.A), Agilent 4294A Impedance Analyzer. Experimental Procedures and Operational Workflow:

Stoichiometric amounts of the oxides were weighed according to nominal composition and ball-mixed for 12 h in alcohol. The mixture was dried in an oven and calcined in an alumina crucible at 1050°C for 4 h in the air. The calcined powders were ball-milled in an isopropyl alcohol as wetting medium using SPEX 8000 Mixer/Mills (60 Hz model) at room temperature for 7 h. The milled powder was compacted at 5 ton to make pellets of size 15 mm in diameter and

5：5 mm in thickness using polyvinyl alcohol (PVA) as a binder. After burning off the binder (PVA), the pellets were sintered in a programmable furnace at temperatures of 1190°C for 2 h in alumina crucibles. Data Analysis Methods:

Phase identification of calcined and sintered powders was carried out using X-ray diffractometer. The experimental densities of the samples were calculated using Electronic Densimeter MD-3005 ALFA MIRAGE. The morphological studies of the sintered sample were carried out using field-emission scanning electron microscopy (FE-SEM). The polarization-electric field (P–E) hysteresis characteristics of the samples were determined using a Precision LC material analyzer. The dielectric and impedance measurement was carried out for the sintered sample using an Agilent 4294A Impedance Analyzer in the frequency and temperature range of 40 Hz–1 MHz and 30–400°C, respectively.