Potassium tantalate substrates for neutron experiments on antiferromagnetic perovskite films

For the study of antiferromagnetism in thin-film materials, neutron diffraction is a particularly important tool, especially since magnetometry experiments are often complicated by the substrate's strong diamagnetic or paramagnetic contribution. However, the substrate, by necessity, has a lattice parameter that is very similar to that of the film, and in most cases is over 1000 times more massive than the film. Therefore, even weak structural distortions in the substrate crystal may complicate the analysis of magnetic scattering from the film. Here we show that in contrast to most other perovskite substrates (including SrTiO₃, LaAlO₃, etc.), KTaO3 provides a uniquely appropriate substrate platform for magnetic diffraction experiments on epitaxial oxide films.