Multiferroic properties of epitaxially stabilized hexagonal DyMnO3 thin films

The authors fabricated epitaxial thin films of hexagonal DyMnO3, which otherwise form in a bulk perovskite structure, via deposition on Pt(111)parallel to Al2O3(0001) and YSZ(111) substrates, each of which has in-plane hexagonal symmetry. The polarization hysteresis loop demonstrated the existence of ferroelectricity in our hexagonal DyMnO3 films at least below 70 K. The observed 2.2 mu C/cm(2) remnant polarization at 25 K corresponded to a polarization enhancement by a factor of 10 compared to that of the bulk orthorhombic DyMnO3. Interestingly, this system showed an antiferroelectriclike feature in its hysteresis loop. Our hexagonal DyMnO3 films showed an antiferromagnetic Neel temperature around 60 K and a spin reorientation transition around 40 K. The authors also found spin-glass-like behavior, which was likely to arise from the geometric frustration of antiferromagnetically coupled Mn spins with an edge-sharing triangular lattice. (c) 2007 American Institute of Physics.