Strain tunable room temperature magnetism

The presence of strong spin–orbit coupling in oxides containing 5d transition metal
ions provides a mechanism for direct coupling between magnetization and the
crystal lattice. In epitaxial films of such compounds strain arising from
lattice mismatch with the substrate can in principle be used to tune the
magnetic properties.   

Using
a novel deposition technique, IRG-2 researchers have grown fully-ordered Sr₂CrReO₆
films which are semiconducting and highly magnetic at room temperature. When
grown on different substrates dramatic changes in magnetization and resistivity
occur. The largest effects are seen when Sr₂CrReO₆ is
grown on Sr₂GaTaO₆
buffer layers (1.6% tensile strain) where the low temperature resistivity
increases by more than two orders of magnitude, and the saturation
magnetization more than doubles, with respect to films grown on a lattice
matched substrate (e.g. SrTiO₃).
Electron microscopy images suggest that changes in the local atomic structure
may be responsible for the change in properties (see the zig-zag
columns of Re on the right).  This effect
could potentially be exploited in a variety of ways, including strain sensors
and magnetoelectric
composite films.