Malia Gundayao

Major: Mechanical Engineering
Mentors: Dr. Brenden Ortiz, Professor Stephen Wilson

Developing Synthesis Methods for Metastable Pyrochlore Oxides; Alloys of Ho(2)Ga(1-x)In(x)SbO(7) and Dy(2)Ga(1- x)In(x)SbO(7)

Ho(2)InSbO(7) and Dy(2)InSbO(7) are metastable pyrochlores while their gallium equivalents Ln(2)GaSbO(7) are stable under ambient con- ditions. Here we synthesize alloys of Ho(2)Ga(1-x)In(x)SbO(7 and Dy(2)Ga(1-x)In(x)SbO(7) to determine the relationship between the chemistry and the pyrochlore stability. We began by alloying Ho(2)Ga SbO(7) with Ho(2)InSbO(7) using ball-milling and conventional heat- ing methods. Our goal is to establish the saturation limit at which the pyrochlore becomes unstable. We then used a new microwave method to discern if we can extend the saturation limit and stabilize our alloys Ho(2)Ga(1-x)In(x)SbO(7) and Dy(2)Ga(1-x)In(x)SbO(7). By utilizing x-ray diffraction and the magnetization measurements we were able to determine that the solubility can be extended using microwave meth- ods, and that the magnetic properties are consistent with a spin ice.