Growth, structure, surface topography and magnetic properties of GdMnO_3 multiferroic epitaxial thin films

摘要

Epitaxial GdMnO_3 thin films were grown in various regimes on (001) NdGaO_3 and (001) SrTiO_3 substrates by RF magnetron sputtering. X-ray analysis revealed that the films grown at a substrate temperature of 650-900 °C are single phase (GdMnO_3 with orthorhombic Pbnm structure). Films grown on NdGaO_3 substrates at lower temperature （< 750 °C） have only one out-of-plane orientation， i.e. GdMnO_3(001)IINdGaO_3(001), whereas films grown at higher temperatures （? 750 °C ） reveal two orientations， i.e. GdMnO_3(001)IINdGaO_3(001) and GdMnO_3(l10)IINdGaO_3(001). These results are confirmed by transmission electron microscopy. Films grown on SrTiO_3 substrates have two orientations, i.e. GdMnO_3(001)IISrTiO_3(001) and GdMnO_3(l 10)||SrTiO_3(001)， in the whole temperature range in which the phase exists. Using atomic force microscopy the correlation between the topography of the films and their crystallographic structure was studied. The magnetic properties of the films differ from those of bulk samples and revealed spin-glass behavior.