Strain-induced magnetic phase transition in SrCoO3-delta thin films

It has been well established that both in bulk at ambient pressure and for films under modest strains, cubic SrCoO< inf>3-δ< /inf> (δ< 0.2) is a ferromagnetic metal. Recent theoretical work, however, indicates that a magnetic phase transition to an antiferromagnetic structure could occur under large strain accompanied by a metal-insulator transition. We have observed a strain-induced ferromagnetic-to-antiferromagnetic phase transition in SrCoO< inf>3-δ< /inf> films grown on DyScO< inf>3< /inf> substrates, which provide a large tensile epitaxial strain, as compared to ferromagnetic films under lower tensile strain on SrTiO< inf>3< /inf> substrates. Magnetometry results demonstrate the existence of antiferromagnetic spin correlations and neutron diffraction experiments provide a direct evidence for a G-type antiferromagnetic structure with Neél temperatures between T< inf>N< /inf>∼135±10K and ∼325±10K, depending on the oxygen content of the samples. Therefore, our data experimentally confirm the predicted strain-induced magnetic phase transition to an antiferromagnetic state for SrCoO< inf>3-δ< /inf> thin films under large epitaxial strain.