Co ferrite films with excellent perpendicular magnetic anisotropy and high coercivity deposited at low temperature

Abstract

The present article describes CoxFe3−xO4 films, which were fabricated at 90 °C by the ferrite-plating method and have the excellent perpendicular magnetic anisotropy and the perpendicular coercivity Hc⊥ above 2 kOe. The films were composed of Co ferrite and Fe3O4 grains. The highest Hc⊥ reached 3 kOe at the composition of Co0.43Fe2.57O4 and the saturation magnetization Ms was 500–550 emu/cc. Hc⊥ was over 2 kOe even for a film thickness of 35 nm without any underlayers. ΔM⊥ evaluation that is measured in the perpendicular direction to the film plane showed that the interactions in the films supported the magnetized state, stabilizing the direct current remanent state. The Mössbauer analyses revealed that the Co0.43Fe2.57O4 films have excellent perpendicular magnetic anisotropy and the magnetization direction inclined from the perpendicular axis due to the demagnetization field. This achievement will open the way to develop the high-density perpendicular recording media even when plastic disks and sheets are used as substrates.

CoFe2O4 and CoFe2O4‐SiO2 Nanoparticle Thin Films with Perpendicular Magnetic Anisotropy for Magnetic and Magneto‐Optical Applications

“…Wet chemistry based deposition methods, on the other hand, are more cost effective and the deposition rate is higher. [ 17 ] Nevertheless, one has to keep in mind that a precise control over the crystallinity and phase purity [ 15 ] is extremely important in magnetic fi lms, because they play a crucial role in determining the magnetic [ 18 ] and magneto-optical properties. From this point of view, using dispersions with preformed nanoparticles of defi ned composition wileyonlinelibrary.com © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim and structure as starting materials for the deposition of thin fi lms is a promising strategy.…”

Dependence of magnetic properties on crystallite size of CoFe2O4nanoparticles synthesised by auto-combustion method

“…Cobalt ferrite (CoFe 2 O 4 ), a kind of inverse-spinel oxide, which belongs to the square group O 7 h (Fd3m), has been widely investigated because of its cubic magnetrocrystalline anisotropy, relatively high H c , moderate saturation magnetisation (M s ), good chemical stability [1,2] and broad prospect of applications in several technological fields, including electronic devices, ferrofluids and high-density information storage [3][4][5][6]. Various methods, including co-precipitation [7,8], hydrothermal synthesis [9,10], sol-gel techniques [11], microemulsion method [12,13], forced hydrolysis method [14] and sonochemical reaction [15], have been reported for preparing CoFe 2 O 4 .…”

Phase Formation and Crystallinity-Dependent Magnetic Parameters of Co1-xFe2+xO4 Nanoparticals

“…(1)(2)(3)(4) . Among spinel ferrites, cobalt ferrite, CoFe 2 O 4 is especially interesting owing to its magnetic properties such as strong anisotropy, high coercivity at room temperature and moderate saturation magnetization, good mechanical and chemical stability (5,6) .…”