The stability field of the piezoelectric/ferroelectric phase of solid solution 0.47Pb(Yb 1/2Nb 1/2)O 3-0.53PbTiO 3 (PYN-PT) has been studied using in situ x-ray diffraction (XRD) and Raman spectroscopy techniques under high pressure and high temperature conditions to observe the evolution of features. PYN-PT remains in the piezoelectric tetragonal phase up to approximately 6.5 GPa at room temperature then transforms to a paraelectric cubic phase, which exhibits local disorder. The cubic phase is stable up to 50 GPa. Based on the high pressure and high temperature XRD results, we present a pressure-temperature phase diagram of PYN-PT which constraints the stability region of the ferroelectric phase. © 2012 American Institute of Physics.