Neutron diffraction and magnetisation studies of Sr₂RuO₄ below 2 K

High resolution neutron powder diffraction and magnetisation measurements have been carried out on the superconductor, Sr₂RuO₄. The powder diffraction data has been refined at high and low temperatures to obtain lattice parameters below the superconducting transition temperature (1.15 K) and at elevated temperatures where Sr₂RuO₄ is used as a substrate for the deposition of YBa₂Cu₃O₇ thin films. No evidence has been found for any lattice distortions between 100 mK and 2 K in Sr₂RuO₄. Magnetisation measurements between 0.7 K and room temperature has indicated the onset of superconductivity at 1.15 K.