کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1488000 1510716 2014 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Magnetic, electric and thermal properties of cobalt ferrite nanoparticles
ترجمه فارسی عنوان
خواص مغناطیسی، الکتریکی و حرارتی نانوذرات فریت کبالت
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
چکیده انگلیسی


• CoxFe3 − xO4 nanograins 4–8 nm in size are a superparamagnetic assembly of monodisperse particles.
• Co1.8Fe1.2O4 presents superparamagnetism at ambient and very high anisotropy constant.
• CoxFe3 − xO4 nanograins have a normal spinel structure contrary to bulk cobalt ferrite.
• CoxFe3 − xO4 nanograins are stable up to 600 °C, thus suitable for high temperature applications.

The electric and magnetic properties as well as the thermal stability of CoxFe3 − xO4 nanopowders, (0.6 < x < 1.8) were investigated. These powders were synthezised using a one pot solvo-thermal route with acetylacetonates as precursors. The properties were linked to the size, morphology, composition of the particles and to the cation distribution. With the exception of x = 0.6, the powders are stable up to 600 °C. Whatever the composition, Co2+ has a strong tendency to occupy tetrahedral sites, contrary to what occurs in bulk ferrites. The nanopowders display a semi conducting behaviour. Between ambient and 500 °C, conduction occurs between Co2+ ↔ Fe3+ pairs, and intergrain conduction predominates. The conductivity is in the 10−7 Ω−1 cm−1 range. The CoxFe3 − xO4 nanopowders behave magnetically as a superparamagnetic assembly of single-domain particles. The magnetocrystalline anisotropy constant is significantly higher for these nanoparticles than for bulk ferrites. Co1.8Fe1.2O4 displays the lowest blocking temperature (200 K) and the highest anisotropy (K = 21 × 106 erg/cm3).

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Materials Research Bulletin - Volume 59, November 2014, Pages 49–58
نویسندگان
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