COEXISTENCE OF DIFFERENT MAGNETIC PHASES IN DY Y SUPERLATTICES CAUSEDBY GROWTH INDUCED NANOSTRUCTURES/

Epitaxial Dy/Y rare earth superlattices were prepared by molecular bea m epitaxy on Ta(211) and Nb(211) buffer layers on alpha-Al2O3(<1(1)ove r bar 00>) and characterized via in situ reflection high-energy electr on diffraction (RHEED), in situ scanning tunneling microscopy (STM) an d ex situ X-ray and neutron diffraction. The Y buffer and the Dy/Y sup erlattice are found to grow strongly faceted on the Ta or Nb(211) buff er, and form 'growth induced' nanostructures with two different superl attice types on both facet surfaces. Magnetic measurements show two co existing magnetic phases that are obtained in the temperature range be low the Neel temperature. We develop a model to interpret this behavio r in connection with the results of structural and magnetic measuremen ts.