SrCO₃ powder (99.99% purity) and IrO2 powder (99.99% purity) were weighted according to the SrIrO3 chemical formula and then milled for 8 hours. The mixtures were sintered at ~950 ^oC for 6 hours to get single-phase SrIrO3 powder and its XRD pattern is shown in Figure 1. The SrIrO3 powder was milled again and then pressed to a target. Such target was sintered at ~1200 ^oC under 1.5 MPa pressure to get the high-density SrIrO3 target (Figure 2). Since SrIrO3 is just stable at 900-1000 ^oC and Sr2IrO4 is more stable above 1100 ^oC, it is not excluded that tiny SrIrO3 component may decompose to Sr2IrO4 and IrO2/Ir in this SrIrO₃ target. Single-phase SrIrO3 film can be prepared through sputtering such a target with an optimizing temperature and oxygen pressure. It is better to not use ultrasonic cleaning to clean such targets.

In fact, both SrIrO₃ target and its films are easy to decompose in humid air or many liquids such as water. 

Figure 1. Single-phase SrIrO3 powder sintered at 950 ^oC for 6 hours, where black lines are standard diffraction peaks of SrIrO3. 

Figure 2. XRD pattern of SrIrO3 target, where red lines are standard diffraction peaks of SrIrO3.