SrCO₃ powder (99.99% purity) and IrO2 powder (99.99% purity) were weighted according to the Sr₂IrO₄ chemical formula and then milled for 8 hours. The mixtures were sintered at ~950 ^oC for 6 hours to get single-phase Sr₂IrO₄ powder and its XRD pattern is shown in Figure 1. The Sr₂IrO₄ 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 Sr₂IrO₄ target (Figure 2). Since SrIrO₃ is just stable at 900-1000 ^oC and Sr2IrO₄ is more stable above 1100 ^oC, less than 1% of Sr₂IrO₄ components decompose to SrIrO₃, SrO, and Ir in this Sr₂IrO₄ target. Some bright Ir particles exist in this target. Single-phase Sr₂IrO₄ 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.

The current diameter is 25.2mm and the thickness is 6.3mm. Since the target may absorb some vapors inside sealing bags and some surfaces may partially decompose, its diameter may be 24.8-25.2, and thickness may be 5.8-6.3mm in March 2020.

In fact, both Sr₂IrO₄ target and its films are easy to decompose in humid air or many liquids such as water. 

Figure 1. Single-phase Sr₂IrO₄ powder sintered at 950 ^oC for 6 hours, where green lines are standard diffraction peaks of Sr₂IrO₄.

Figure 2. XRD pattern of Sr₂IrO₄ target, where blue lines are standard diffraction peaks of Sr₂IrO₄.