This project focuses on the utilization of molten hydroxides in sealed silver tubes as a route for synthesizing high quality single crystals of complex transition metal containing oxides. Our group has developed a unique silver tube approach, which has resulted in the preparation of over 100 new compositions with a variety of new structure types, exhibiting novel and enhanced properties, such as photoluminescence.

Our recent advances include the single crystal growth of new complex transition metal containing oxides, including two perovskite related oxides, Sr6Co5O15 and Sr5Co4O12, which are of interest for thermoelectric applications, as well as a unique iron containing oxide, Ba4KFe4O9 possessing isolated Fe6O18 rings – “iron crowns”.

An Iron “Crown”. I would have preferred Gold !

Structures of Sr6Co5O15 (L) and Sr5Co4O12 (R)

Synthesis of Complex Metal Oxides Hans-Conrad zur Loye, University of South Carolina, DMR 0804209

100K 300K

Ba4KFe4O9

e3=0.000

-0.8 -0.4 0.0 0.4 0.8 e1

-0.8

-0.4

0.0

0.4

0.8

e2

We had a large number of undergraduates participate in this research project during the past year. Kristina Wichmann was a visiting student from Germany, who grew a series of Eu+3 doped LnKNaTaO6 luminescent crystals. Jackie Cantwell succeeded in the crystal growth of two other luminescent series of oxides, LnLiO2 and La4Ga2O9, while Chavis Stackhouse grew crystals of LnNaTiO4 and several new hafnium oxides. Manuscripts are in preparation for all of these projects.

Dr. Irina Roof obtained her Ph.D. Qingbiao Zhao will finish next year and a new student, Cory Read, joined.

Synthesis of Complex Metal Oxides Hans-Conrad zur Loye, University of South Carolina, DMR 0804209

Optical picture of powder (L) and crystals (M) ofLa1-xEuxKNaTaO5 x = 0.1 and crystals of La4Ga2O9 (R)

Fluorescence data EuLiO2 (L) GdLiO2 (M); Cu2O (R)

Sr6Co5O15 (L), K4Hf5O12 (M), Uranium containing oxide (R)