Magnetic order in Sr2RuO4 under large uniaxial stress

Sr2RuO4 is a well-studied unconventional superconductor which may be mediated by spin fluctuations. The pairing wavefunction (gap function) of the superconducting state appears to break time reversal symmetry, which would make it an electronic analogue of superfluid helium 3. It has not been possible to construct a pairing wavefunction which consistently describes the properties of Sr2RuO4. Our studies show that the electronic structure and superconducting properties of Sr2RuO4 evolve rapidly with uniaxial stress e.g. Tc increases by a factor of two. We recently carried out a muon spin rotation study under uniaxial stress and found magnetic order at 1.0 GPa. The co-existence of superconductivity and magnetic order will be important in understanding the unique superconductivity in Sr2RuO4. Here we propose to determine the structure and ordering wavevector of this new magnetic order.