کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
8158351 1524879 2013 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Effect of high-energy ball milling time on structural and magnetic properties of nanocrystalline cobalt ferrite powders
ترجمه فارسی عنوان
اثر زمان آسیاب توپ با انرژی بالا بر خواص ساختاری و مغناطیسی پودر فریت نانو کریستالین کبالت
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه فیزیک و نجوم فیزیک ماده چگال
چکیده انگلیسی
Cobalt ferrite nanocrystals synthesized by conventional and size-controlled coprecipitation methods were treated by high-energy ball milling, HEBM, in order to study the effect of crystal size reduction and/or strain on the resulting magnetic properties. Processed nanocrystals were characterized by X-ray diffraction, Brunauer, Emmett, and Teller surface area analysis, transmission electron microscopy (TEM), and vibrating sample magnetometry. The cobalt ferrite nanocrystals exhibited crystal size reduction from initial values (average crystallite sizes of 12±1 nm and 18±3 nm, respectively) down to 10 nm after HEBM for 10 h. The specific surface area was decreased by milling (from 96.5 to 59.4 m2/g; for the 12 nm cobalt ferrite nanocrystals), due to particles aggregation. TEM analyses corroborated the aggregation of the nanoparticles at such long milling times. The same cobalt ferrite nanocrystals exhibited a rise in coercivity from 394 to 560 Oe after 5 h ball milling which was attributed to the introduction of strain anisotropy, namely point defects, as suggested by the systematic shift of the diffraction peaks towards higher angles. In turn, the magnetic characterization of the starting 18 nm-nanocrystals reported a drop in coercivity from 4506 Oe to 491 Oe that was attributed predominantly to size reduction within the single domain region. A correlation between particle size, cationic distribution, and HEBM processing conditions became evident.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Magnetism and Magnetic Materials - Volume 341, September 2013, Pages 17-24
نویسندگان
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