{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T10:01:26Z","timestamp":1789984886230,"version":"4.0.1"},"reference-count":26,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T00:00:00Z","timestamp":1789689600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Universidad Nacional de Colombia and MinCiencias","id":[{"id":"https:\/\/ror.org\/059yx9a68","id-type":"ROR","asserted-by":"crossref"}]},{"id":[{"id":"https:\/\/ror.org\/059yx9a68","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nanomaterials"],"abstract":"<jats:p>In this work, TiO2 and TiO2:Co nanotubes were fabricated via electrochemical anodization, using Ti (99.99% purity) and Ti\/Co foils as the anode and cathode. Cobalt was deposited onto the Ti foils using the DC magnetron sputtering technique under a working pressure of 2.5 \u00d7 10\u22122 Torr. The resulting nanotubes exhibited wall nodes and an average length of 308.6 \u00b1 13.07 nm for TiO2 and 92.63 \u00b1 2.846 nm for TiO2:Co. The synthesized structures were characterized by X-ray diffraction (XRD), identifying anatase as the predominant phase, accompanied by an amorphous halo. Two types of MSM devices were fabricated to study bulk and surface conduction: a transverse configuration (TE\/(TiO2, TiO2:Co)\/Ti), with top electrodes (TE) of Al or Au, and a coplanar configuration (Al\/TiO2\/Al). Surface topography and surface-potential variations were investigated using Atomic Force Microscopy (AFM) and Kelvin Probe Force Microscopy (KPFM), respectively. The device behavior is mainly governed by the TE\/TiO2 junction due to the absence of an energy barrier at the TiO2\/Ti interface. All samples exhibit asymmetric I\u2013V behavior with higher conduction under positive bias. The Au\/TiO2\/Ti device showed the lowest resistance among the Ti BE structures, displaying Schottky behavior with low reverse current leakage and a shift in the zero-current crossing depending on the scan direction. Barrier heights near the zero-current crossing, calculated via the thermionic emission model, were 0.91 eV and 0.70 eV for the reverse and forward directions, respectively. Ideality factors and series resistance exceeded 6.8 and 40 k\u03a9, respectively, suggesting additional transport mechanisms. In addition, magnetization as a function of the applied field was generated in the TiO2:Co nanotubes, evidencing their ferromagnetic-like behavior.<\/jats:p>","DOI":"10.3390\/nano16181179","type":"journal-article","created":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T08:03:47Z","timestamp":1789977827000},"page":"1179","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Interface-Dependent Transport and Resistive Switching in TiO2 and TiO2:Co Nanotubes for Resistive Memories"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0005-8794-2301","authenticated-orcid":false,"given":"Y.","family":"Porras Ram\u00edrez","sequence":"first","affiliation":[{"name":"Grupo de Materiales Nanoestructurados y sus Aplicaciones, Departamento de F\u00edsica, Universidad Nacional de Colombia\u2014Bogot\u00e1, Bogota 110001, 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Colombia"},{"name":"Grupo de Investigaci\u00f3n en Nanotecnolog\u00eda, Bioingenier\u00eda y Transferencia Tecnol\u00f3gica, Cluster in Convergent Sciences and Technologies, Universidad Central, Bogota 110311, Colombia"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"funding-acquisition","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"software","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"conceptualization","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5355-2640","authenticated-orcid":false,"given":"A.","family":"Dussan","sequence":"additional","affiliation":[{"name":"Grupo de Materiales Nanoestructurados y sus Aplicaciones, Departamento de F\u00edsica, Universidad Nacional de Colombia\u2014Bogot\u00e1, Bogota 110001, 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review of oxide based dilute magnetic semiconductors","volume":"696","author":"Bhardwaj","year":"2025","journal-title":"Phys. B Condens. Matter"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"107890","DOI":"10.1016\/j.rinp.2024.107890","article-title":"Magnetic-resistive random access memories based on diluted Co-TiO2 nanotubes","volume":"63","author":"Jaimes","year":"2024","journal-title":"Results Phys."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"117986","DOI":"10.1016\/j.mseb.2025.117986","article-title":"Improved resistive switching characteristics of Au\/TiO2\/Au memristors on PDMS substrates with pyramid arrays","volume":"314","author":"Lee","year":"2025","journal-title":"Mater. Sci. Eng. B"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1016\/j.sse.2016.07.006","article-title":"A review of emerging non-volatile memory (NVM) technologies and applications","volume":"125","author":"Chen","year":"2016","journal-title":"Solid-State Electron."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"155674","DOI":"10.1016\/j.jallcom.2020.155674","article-title":"Magnetic switching control in Co\/TiO2 bilayer and TiO2:Co thin films for Magnetic-Resistive Random Access Memories (M-RRAM)","volume":"840","author":"Quiroz","year":"2020","journal-title":"J. Alloys Compd."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"115722","DOI":"10.1016\/j.sna.2024.115722","article-title":"Flame intensity sensor based on the resistive and memory properties of spintronic memristor","volume":"377","author":"Wen","year":"2024","journal-title":"Sens. Actuators A Phys."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"113842","DOI":"10.1016\/j.sna.2022.113842","article-title":"A novel nuclear radiation cumulant sensor based on spintronic memristor","volume":"346","author":"Wen","year":"2022","journal-title":"Sens. Actuators A Phys."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"8390","DOI":"10.1038\/s41467-023-44019-y","article-title":"Hydrophobically gated memristive nanopores for neuromorphic applications","volume":"14","author":"Paulo","year":"2023","journal-title":"Nat. Commun."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"714","DOI":"10.1038\/s42256-023-00680-y","article-title":"Uncertainty quantification via a memristor Bayesian deep neural network for risk-sensitive reinforcement learning","volume":"5","author":"Lin","year":"2023","journal-title":"Nat. Mach. Intell."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"2401386","DOI":"10.1002\/advs.202401386","article-title":"2D Materials in Advanced Electronic Biosensors for Point-of-Care Devices","volume":"11","author":"Nisar","year":"2024","journal-title":"Adv. Sci."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2569","DOI":"10.1007\/BF03038386","article-title":"Neutron diffraction Investigation of Ordered Structures in the Titanium-Oxigen System","volume":"1","author":"Kornilov","year":"1970","journal-title":"Metall. Trans."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"138437","DOI":"10.1016\/j.tsf.2020.138437","article-title":"Substoichiometric Tuning of the Electronic Properties of Titania","volume":"717","author":"Bell","year":"2021","journal-title":"Thin Solid Films"},{"key":"ref_13","first-page":"083503","article-title":"The energy barrier at noble metal\/TiO2 junctions","volume":"106","author":"Lajvardi","year":"2015","journal-title":"Appl. Phys."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2100121","DOI":"10.1002\/pssa.202100121","article-title":"Numerical Modeling of Schottky Barrier Diode Characteristics","volume":"218","author":"Splith","year":"2021","journal-title":"Phys. Status Solidi A"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"18287","DOI":"10.1007\/s10854-019-02183-2","article-title":"Effect of annealing temperature on structural and electrical properties of Al\/Nb-doped TiO2 Schottky diodes on Pt-Si substrates","volume":"30","author":"Yu","year":"2019","journal-title":"J. Mater. Sci. Mater. Electron."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"044005","DOI":"10.7567\/1882-0786\/ab08ad","article-title":"Near unity ideality factor for sidewall Schottky contacts on un-intentionally doped \u03b2-Ga2O3","volume":"12","author":"Zhang","year":"2019","journal-title":"Appl. Phys. Express"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"054303","DOI":"10.1063\/1.5093277","article-title":"Effect of hydrogen ions in the adsorbed water layer on the resistive switching properties of hexagonal WO3 nanowire","volume":"126","author":"Zhao","year":"2019","journal-title":"J. Appl. Phys."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"954","DOI":"10.1016\/j.apsusc.2018.01.124","article-title":"Structural and chemical analysis of TiO2 nanotube surface for dye-sensitized solar cells","volume":"439","author":"Endo","year":"2018","journal-title":"Appl. Surf. Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"4522","DOI":"10.1038\/srep04522","article-title":"Memory Impedance in TiO2 based Metal-Insulator-Metal Devices","volume":"4","author":"Qingjiang","year":"2014","journal-title":"Sci. Rep."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"154006","DOI":"10.1016\/j.jallcom.2020.154006","article-title":"Magnetic behavior and conductive wall switching in TiO2 and TiO2:Co self-organized nanotube arrays","volume":"825","author":"Quiroz","year":"2020","journal-title":"J. Alloys Compd."},{"key":"ref_21","first-page":"1","article-title":"Optical properties and bipolar resistive switching of ZnO thin films deposited via DC magnetron sputtering","volume":"74","author":"Quiroz","year":"2021","journal-title":"Chin. J. Phys."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"581","DOI":"10.1007\/s10853-020-05282-2","article-title":"Super-exchange interaction model in DMOs: Co doped TiO2 thin films","volume":"56","author":"Quiroz","year":"2021","journal-title":"J. Mater. Sci."},{"key":"ref_23","unstructured":"Stiller, M. (2020). Defect Induced Magnetism in Titanium Dioxide. [PhD Thesis, University of Leipzig, Faculty of Physics and Earth Sciences]."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Kumar, S., Kumari, K., Kumar, A., Koo, B.H., Kumar, R., Alvi, P.A., and Dalela, S. (2023). 24-Magnetism of titanium dioxide. Defect-Induced Magnetism in Oxide Semiconductors, Elsevier.","DOI":"10.1016\/B978-0-323-90907-5.00026-9"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"195145","DOI":"10.1103\/PhysRevB.98.195145","article-title":"Fe-incorporated TiO2 nanotube arrays: Electronic structure and magnetic response","volume":"98","author":"Hosseinpour","year":"2018","journal-title":"Phys. Rev. B"},{"key":"ref_26","unstructured":"Dussan, A., Quiroz, H.P., and Calder\u00f3n, J.A. (2020). Nanomateriales que Revolucionan la Tecnolog\u00eda: Perspectivas y Aplicaciones en Espintr\u00f3nica, Editorial UN."}],"container-title":["Nanomaterials"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-4991\/16\/18\/1179\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T09:04:17Z","timestamp":1789981457000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-4991\/16\/18\/1179"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,18]]},"references-count":26,"journal-issue":{"issue":"18","published-online":{"date-parts":[[2026,9]]}},"alternative-id":["nano16181179"],"URL":"https:\/\/doi.org\/10.3390\/nano16181179","relation":{},"ISSN":["2079-4991"],"issn-type":[{"value":"2079-4991","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,18]]}}}