The J1-J2 model on the square lattice has attracted considerable attention due to many interesting phases emerging as a result of a simple model, including spin-liquid and spin-nematic regimes. We have previously extended the J1-J2 phase diagram by measuring the first-ever frustrated ferromagnets. Here, we are focusing on the theoretically proposed spin-liquid (SL) regime, with no compounds ever measured. There is strong evidence that PbVO3 lies inside (or extremely close) to this SL region. Experiments have been so far hindered due to the problems of insufficient sample size and quality that we have recently been able to overcome. We therefore propose to measure the system on D20, in order to resolve the nature of the ground state, which remains controversial so far. Furthermore, we propose to measure the excitation spectrum and probe quantum fluctuations in PbVO3 on IN4C, which ideally matches the energy scale of this system (~20meV). Theory predicts a gapped excitation spectrum for the SL phase on the square lattice.