Single crystal growth

High quality single crystals of Ca10-4-8 were grown using the self-flux method. The stoichiometric amounts of high purity calcium shot (99.999% Alfa Aesar), Pt powder (99.95% Alfa Aesar), iron powder (99.95% Alfa Aesar), and arsenic powder (99.999% Alfa Aesar) are mixed in the ratio 10:4:10:18. The mixture is placed in an alumina crucible and sealed in a quartz tube under vacuum. The whole assembly is heated in a box furnace to 700 °C at a rate of 150 °C/h and is held at this temperature for 5 h. It is further heated to 1100 °C at a rate of 80 °C/h where it is held for 50 h, and then cooled to 1050 °C at a rate of 1.25 °C/h. It is further cooled to 500 °C at a rate of 5.5 °C/h and finally cooled down to room temperature by turning off the power. Shiny black plate-like single crystals are obtained without requiring any additional process. These crystals have a typical size of 6 × 6 × 0.2 mm³.