Control of Oxygen Nonstoichiometry and Magnetic Property of MnCo2O4 Thin Films Grown by Atomic Layer Deposition

Spinel-structured (Mn,Co)3O4 thin films were reproducibly fabricated by atomic layer deposition (ALD) using Mn(thd)3, Co(thd)2, and ozone as precursors. A full control of the cation ratio was achieved in the temperature interval 140−160 °C within which also the growth rate remained constant. Precise control of the oxygen content of as-deposited MnCo2O4+δ films was achieved through postdeposition heat treatments at prefixed temperatures in air and N2 atmospheres, as evidenced from the monotonous increases of both the unit cell volume and the Curie temperature (TC) with increasing annealing temperature/decreasing oxygen partial pressure. The TC value varied from 92 K for the as-deposited MnCo…