Effect of Symmetry Breaking on Interlayer Exchange Coupling and Electrical Conduction in SrRuO 3 -PrMnO 3 Superlattices
Résumé
The breaking of orthorhombic to tetragonal crystal symmetry is realized
by increasing the PrMnO3 layer thickness in the superlattices consisting
two ferromagnets, SrRuO3 and PrMnO3. The octahedral rotation pattern
is a+c−c− and a0a0c− type for the superlattices with orthorhombic and
tetragonal phase, respectively, inferred in the simulated projected density
of states. The 15% reduction in dz2 orbital occupancy due to the a0a0c−
type octahedral rotation compared to that of the a+c−c− type suggests
the presence of stronger antiferromagnetic (AFM) coupling. The larger
orbital overlapping leads to a stronger spin–orbit coupling, associated
with a shift of 42.8% of the minor in-plane field cooled (FC) magnetic
hysteresis loop(M(H)) along the magnetization axis in orthorhombic
superlattices. While, minor in-plane FC M(H) shifts along the field axis due
to the strong AFM coupling in tetragonal superlattices. In field-dependent
magnetoresistance, the rotation of spins in the antiferromagnetically
coupled interfacial layers is detected as a unique anomaly, which is stronger
in the superlattices for the biased spins and tetragonal symmetry than the
pinned spins and orthorhombic symmetry. The results demonstrate that
the tuning of interfacial exchange coupling and spin-dependent transport
by controlling structural distortion could be used as a tool in fabricating
modern spintronics-based devices.