Enhancement of ferromagnetism in BaFeO_3-KTa_(0.47)Nb_(0.53)O_3 multilayers compared to pseudo-cubic BaFeO_3 thin film grown by pulsed laser deposition

摘要

Oxide multilayer hetero-structure of BaFeO3-KTao.47Nbo.53O3 have been grown using the pulsed laser deposition and the ex situ annealed in a flowing oxygen atmosphere. The multilayer has been characterized using X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. Magnetic properties have been studied via SQUID measurements. Magnetization in the multilayer structure shows significant improvement compared to previous measurements of bare BaFeO_3. Measuring magnetization as a function of temperature and fitting the resulting M-Tcurves to Bloch's 3/2 law, yields an estimated Curie temperature (T_C) of around 425 K and a P factor of around 1.5, consistent with magnetization from a three dimensional crystal structure. In spite of using a room temperature ferroelectric KTa_(0.47)Nb_(0.53)O_3 composition, no evidence of ferroelectricity was observed in multi-layer structure.