Structural and spectroscopic characterization of Ce0.4Zr0.6O2 crystalline rods grown by the Laser Floating Zone method

A structural and spectroscopic characterization of crystalline rods of Ce0.4Zr0.6O2 grown by the laser floating zone (LFZ) method is presented. A precursor rod of Ce0.4Zr0.6O2 composition was sintered at 1500 degrees C in air atmosphere and then processed by the LFZ technique with a CO2 laser. The processed material was characterized by XRD, SEM and Raman spectroscopy. In the as-grown, dark-color processed rod, the Raman spectrum evolves radially from a t'-like one, corresponding to Ce0.37Zr0.63O2 composition, at the edge of the rod, to a very broad and weak, cubic-like one, at the center. The degree of Cerium reduction and oxygen non-stoichiometry were determined through measurements of the electronic Raman spectrum of Cell. A strong Ce3+ signal was found at the core of the rod, indicating strong reduction, whereas no Ce3+ signal was detected at the edge. To restore oxygen and Ce4+ content a section of the fiber was reoxidized at 620 degrees C for 24 h. A very homogeneous spectrum was found in the reoxidized sample, that was assigned to a t'-phase of composition Ce(0.42)Z(0.58)O(2).