An apparatus comprising a memory array comprising access lines. Each of the access lines comprises an insulating material adjacent a bottom surface and sidewalls of a base material, a first conductive material adjacent the insulating material, a second conductive material adjacent the first conductive material, and a barrier material between the first conductive material and the second conductive material. The barrier material is configured to suppress migration of reactive species from the second conductive material. Methods of forming the apparatus and electronic systems are also disclosed.