Viviana B. Daboin , Julieta S. Riva , Paula G. Bercoff
{"title":"Magnetic behavior of nanofilms prepared by assembling different Co ferrite nanoparticles","authors":"Viviana B. Daboin , Julieta S. Riva , Paula G. Bercoff","doi":"10.1016/j.materresbull.2024.113229","DOIUrl":null,"url":null,"abstract":"<div><div>We study the magnetic characteristics of nanofilms composed of CoFe<sub>2</sub>O<sub>4</sub> nanoparticles synthesized by thermal decomposition (TD) and self-combustion (SC) methods, assembled on glass substrates using the Langmuir-Blodgett technique. Despite both synthesis methods render crystalline Co ferrite nanoparticles, the differences in particle size and saturation magnetization are notable; however, both nanofilms reveal a ferrimagnetic behavior and display a significant surface contribution to the net magnetization at temperatures below 50 K. This effect is attributed to the nanoparticles' surface spins misaligning with the spins of the ordered core and freezing into a disordered structure. Effective anisotropy <em>K<sub>eff</sub></em> values were determined, obtaining similar values to the bulk material (<em>K<sub>eff</sub></em> ∼2 × 10<sup>5</sup> <em>J</em>/m<sup>3</sup>) for the nanofilm made of TD nanoparticles, while the nanofilm prepared with SC nanoparticles presents an enhanced value (<em>K<sub>eff</sub></em>=5 × 10<sup>5</sup> <em>J</em>/m<sup>3</sup>). The temperature-dependent saturation magnetization curves were fitted with the modified Bloch's law and an additional term that corresponds to the frozen spins.</div></div>","PeriodicalId":18265,"journal":{"name":"Materials Research Bulletin","volume":"184 ","pages":"Article 113229"},"PeriodicalIF":5.3000,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Materials Research Bulletin","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0025540824005580","RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
We study the magnetic characteristics of nanofilms composed of CoFe2O4 nanoparticles synthesized by thermal decomposition (TD) and self-combustion (SC) methods, assembled on glass substrates using the Langmuir-Blodgett technique. Despite both synthesis methods render crystalline Co ferrite nanoparticles, the differences in particle size and saturation magnetization are notable; however, both nanofilms reveal a ferrimagnetic behavior and display a significant surface contribution to the net magnetization at temperatures below 50 K. This effect is attributed to the nanoparticles' surface spins misaligning with the spins of the ordered core and freezing into a disordered structure. Effective anisotropy Keff values were determined, obtaining similar values to the bulk material (Keff ∼2 × 105J/m3) for the nanofilm made of TD nanoparticles, while the nanofilm prepared with SC nanoparticles presents an enhanced value (Keff=5 × 105J/m3). The temperature-dependent saturation magnetization curves were fitted with the modified Bloch's law and an additional term that corresponds to the frozen spins.
期刊介绍:
Materials Research Bulletin is an international journal reporting high-impact research on processing-structure-property relationships in functional materials and nanomaterials with interesting electronic, magnetic, optical, thermal, mechanical or catalytic properties. Papers purely on thermodynamics or theoretical calculations (e.g., density functional theory) do not fall within the scope of the journal unless they also demonstrate a clear link to physical properties. Topics covered include functional materials (e.g., dielectrics, pyroelectrics, piezoelectrics, ferroelectrics, relaxors, thermoelectrics, etc.); electrochemistry and solid-state ionics (e.g., photovoltaics, batteries, sensors, and fuel cells); nanomaterials, graphene, and nanocomposites; luminescence and photocatalysis; crystal-structure and defect-structure analysis; novel electronics; non-crystalline solids; flexible electronics; protein-material interactions; and polymeric ion-exchange membranes.