Paper detail

Structural, electrical and magnetic properties of magnetoelectric GdMnO3 thin films prepared by sol-gel method

In this work, we analysed GdMnO3 magnetoelectric thin films prepared by a general sol-gel method. The film formation temperature is analysed by termogravimetric analysis, while the lattice parameters of the Pbnm orthorhombic films are determined from the analysis of the x-ray spectra. The x-ray results also reveal that GdMnO3 films are under compression along the b axis. The lattice dynamic analysis carried out by Raman spectroscopy confirms the formation of films with a Pbnm orthorhombic structure. Moreover, the analysis of the Raman spectra suggests that besides film-substrate interaction, texture and grain size influence can alters lattice dynamics relative to bulk ones. Magnetic measurements shows that the films response is different of the observed in ceramic and single crystal; mainly, in the shape and temperature where the transitions taking place. The magnetic study also reveals that GdMnO3 films are paramagnetic above 80 K, showing a ferromagnetic response at low temperatures (T=<15 K). The dielectric analysis carried out in the 850C annealed films shows the formation of a relaxation process at low temperature, which is associated with a polaronic process. Moreover, it is also observed a small anomaly at T~27 K that might be related with the magnetic transition taking place in this temperature range.