1：Experimental Design and Method Selection:

The study used chemical solution deposition (CSD) to prepare PZT thin films with a buffer layer structure (SRO/LSCO/LNO) on Si substrates to achieve near strain-free conditions. The rationale was to control thermal stress and lattice strain by adjusting layer thicknesses and compositions.

2：Sample Selection and Data Sources:

PZT thin films with compositions ranging from Zr/Ti = 50/50 to 58/42 were deposited. Samples were characterized using X-ray fluorescence (XRF) for composition, X-ray diffraction (XRD) for residual stress and crystal structure, scanning electron microscopy (SEM) for morphology, and atomic force microscopy (AFM) with piezoresponse force microscopy (PFM) mode for piezoelectric properties.

3：List of Experimental Equipment and Materials:

Equipment included XRF (S8 TIGER; Bruker AXS GmbH), XRD (D8 Advance; Bruker AXS GmbH) with polycapillary optics and collimator, AFM (SPI3800N with SPA-400 scanner; Hitachi High-Tech Science Corporation), and sputtering for top electrodes. Materials included precursor solutions for LNO, LSCO, SRO, and PZT layers, Si substrates, and gold for electrodes.

4：Experimental Procedures and Operational Workflow:

The buffer layers (LNO, LSCO, SRO) and PZT layers were deposited sequentially by CSD. Layer thicknesses were controlled (LNO: 120 nm, LSCO: 90 nm, SRO: 200 nm, PZT: 640 nm). After deposition, samples were characterized: composition by XRF, residual stress by XRD sin2ψ method, morphology by SEM, and piezoelectric response by AFM/PFM with voltage application.

5：Data Analysis Methods:

Residual stress was analyzed using XRD data fitted with Voigt function. Piezoelectric effective d33 values were calculated from displacement measurements during voltage application, with data from multiple points per sample.