García, M. A..Ruiz González, M. L.Quesada, A.Gónzalez Calbet, J. M.Hernando Grande, Antonio2023-06-202023-06-202005-06-030031-900710.1103/PhysRevLett.94.217206https://hdl.handle.net/20.500.14352/52098©2005 The American Physical Society. This work has been partially supported by the University Complutense Project No. PR1/05-13325. Partial support from the EU Network of Excellence SANDIE is also acknowledged.In this Letter, we experimentally show that the room temperature ferromagnetism in the Mn-Zn-O system recently observed is associated with the coexistence of Mn^(3+) and Mn^(4+) via a double-exchange mechanism. The presence of the ZnO around MnO_2 modifies the kinetics of MnO_2 →Mn_2O_3 reduction and favors the coexistence of both Mn oxidation states. The ferromagnetic phase is associated with the interface formed at the Zn diffusion front into Mn oxide, corroborated by preparing thin film multilayers that exhibit saturation magnetization 2 orders of magnitude higher than bulk samples.engjournal articlehttp://dx.doi.org/10.1103/PhysRevLett.94.217206https://journals.aps.orgopen access538.9Room-temperatureDoped ZnOTransitionFísica de materialesFísica del estado sólido2211 Física del Estado Sólido