The structural and magnetic properties of barium ferrite powders prepared by the sol—gel method

Abstract

In this paper, M-type hexagonal barium ferrite powders are synthesized using the sol—gel method. A dried precursor heated in air is analyzed in the temperature range from 50 to 1200 °C using thermo-gravimetric analysis and differential scanning calorimetry. The effects of the additives and the cacinating temperature on the magnetic properties are investigated, and the results show that single-phase barium ferrite powders can be formed. After heat-treating at 950 °C for 4h with 3 wt% additive, the coercivity and saturation magnetization are found to be 440 Oe and 57.9 emu/g, respectively.

Finite-width Laplacian sum rules for 2++ tensor glueball in the instanton vacuum model

“…(e) We note here that a recent phenomenological analysis [68] predicts the mass of the lowest lying tensor glueball mass is 1.40 ± 0.14GeV, near but lower than our present result.…”

Pengaruh Penambahan Aditif Bi2O3 Terhadap Karakteristik Barium Heksaferit Hasil Sintesis dengan Metode Sol-Gel

“…Barium heksaferit dengan rumus kimia BaFe 12 O 19 , merupakan salah satu magnet permanen yang bersifat stabil, mempunyai magnet kristal anisotrop cukup besar, suhu Curie tinggi, korosi resistivitasnya tinggi, densitas rendah, dan mempunyai nilai saturasi megnetik relatif tinggi (Li et al 2012;Kanagesan, Mansor, dan Sinnappan 2014). Dengan kelebihan tersebut barium heksaferit sangat banyak digunakan di berbagai bidang industri, seperti media perekaman magnetik (Onayagi et al 2016), aplikasi microwave (Durmus, Durmus, dan Kavas 2015) dan sebagai Multi-Layer Ionization Chamber (MLIC) yang merupakan komponen penting dari camcordes, pager dan notebook computer (Iqbal, Mir, dan Alam 2010) Barium heksaferit berukuran nano sangat diperlukan dalam aplikasi perekaman maupun microwave absorber.…”

“…Ada beberapa cara yang dapat dilakukan untuk pembuatan barium heksaferit pada suhu rendah dan tidak memerlukan proses milling diantaranya adalah kopresipitasi kimia (Kwak et al 2012), sol-gel (Li et al 2012;Meng et al 2014;Atay 2016), mikroemulsi (Sindhuja dan Joseyphus 2015; Ataie dan Montazeri-Pour 2011) dan hidrotermal (Sindhuja dan Joseyphus 2015). Diantara metode tersebut sol-gel merupakan metode yang sederhana, mudah dikendalikan dan tidak perlu suhu tinggi (Kwak et al 2012;Ganapathi 2009).…”

“…Untuk mencapai tujuan tersebut dilakukan variasi jumlah penambahan aditif, yang berfungsi untuk menurunkan suhu sintering, meningkatkan faktor kualitas dan cut-off frekuensi (Li et al 2012 22,79;30,22;32,08;34,03;36,97;40,17;42,30;54,93;56,46 dan 62,94 (Widyastuti et al 2012 …”

Enhancement of microwave absorption of nanocomposite BaFe12O19/α-Fe microfibers

“…[22,23] M-type barium ferrites (BaFe 12 O 19 , BaM), due to their excellent resistance to oxidation, high natural resonance frequency and wide bandwidth, have been well known as absorbing materials. [24,25] However, up to now, there has been no report on the microwave absorption property of nanocomposite microfibers comprising the barium ferrite and α-Fe. Therefore, in the present work, the microstructures, magnetic properties and microwave absorptions for the nanocomposite BaFe 12 O 19 /α-Fe microfibers with different mass ratios are investigated and the effects of heterostructure on their microwave absorption performance are also analyzed.…”