{"title":"Hybridized microstructures of oxygen-defective HfO2−x films produced by controlling oxidation of metallic Hf foil","authors":"Mitsuhiro Matsuda, Kai Imamura, Kaori Kusuda, Masahiro Shozaki, Kenji Shida, Motohide Matsuda","doi":"10.1111/jace.20362","DOIUrl":null,"url":null,"abstract":"<p>We successfully produced a dopant-free oxygen-defective HfO<sub>2−</sub><i><sub>x</sub></i> film that exhibit room-temperature ferromagnetism via a heat treatment of metallic Hf foil at 1673 K for 10 h under an oxygen partial pressure of 1.0 × 10<sup>−4</sup> atm. The sample, which exhibits ∼50% transmission of visible light, demonstrates room-temperature ferromagnetism, with saturation and residual magnetizations of ∼0.05 emu/g and ∼0.005 emu/g, respectively. The HfO<sub>2−</sub><i><sub>x</sub></i> film comprises columnar grains several hundred nanometers wide and several micrometers long. High-angle annular dark-field scanning electron microscopy observations indicated that the tetragonal HfO<sub>2</sub> structure was distributed in nanodomains within the monoclinic HfO<sub>2</sub> grains; that is, the films exhibited a hybridized microstructure. The tetragonal HfO<sub>2</sub> structure would be mainly due to the introduction of oxygen deficiencies, which led to the room-temperature ferromagnetism.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 5","pages":""},"PeriodicalIF":3.5000,"publicationDate":"2025-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of the American Ceramic Society","FirstCategoryId":"88","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1111/jace.20362","RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATERIALS SCIENCE, CERAMICS","Score":null,"Total":0}
引用次数: 0
Abstract
We successfully produced a dopant-free oxygen-defective HfO2−x film that exhibit room-temperature ferromagnetism via a heat treatment of metallic Hf foil at 1673 K for 10 h under an oxygen partial pressure of 1.0 × 10−4 atm. The sample, which exhibits ∼50% transmission of visible light, demonstrates room-temperature ferromagnetism, with saturation and residual magnetizations of ∼0.05 emu/g and ∼0.005 emu/g, respectively. The HfO2−x film comprises columnar grains several hundred nanometers wide and several micrometers long. High-angle annular dark-field scanning electron microscopy observations indicated that the tetragonal HfO2 structure was distributed in nanodomains within the monoclinic HfO2 grains; that is, the films exhibited a hybridized microstructure. The tetragonal HfO2 structure would be mainly due to the introduction of oxygen deficiencies, which led to the room-temperature ferromagnetism.
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