We report the synthesis, crystal structure, and magnetic properties of a new Kitaev honeycomb cobaltate, KCoAsO4, which crystallizes in two distinct forms: P2/c and R \(\overline{3 }\) space groups. Magnetic measurements reveal ordering temperatures of ~ 14 K for the P2/c structure and ~ 10.5 K for the R \(\overline{3 }\) structure. The P2/c-type KCoAsO4 sample exhibits a complex temperature-field phase diagram, including a field-induced phase, while the R \(\overline{3 }\) -type KCoAsO4 shows a simpler phase diagram with a single magnetically ordered phase. The observed differences in magnetic properties are attributed to subtle structural variations, strongly suggesting that local structural changes play a crucial role in determining the magnetism of cobaltate-based Kitaev materials.
