Impacts of yttrium substitution on FMR line-width and magnetic properties of nickel spinel ferrites

The influence of yttrium (Y) substitution on ferromagnetic resonance (FMR), initial permeability, and magnetic properties of NiFe2O4 ferrites were investigated. It was observed that the FMR line-width decreases with yttrium contents for the substitution level 0 <= x <= 0.06. Beyond this, the FMR line-width increases with yttrium contents. The nominal composition NiY0.12Fe1.88O4 exhibited the smallest FMR line-width,similar to 282 Oe. A significant change in FMR position of nickel-yttrium (Ni-Y) ferrites was observed and it found to exist between 4150 and 4600 Oe. The saturation magnetization was observed to decrease with the increase of yttrium contents and this was referred to the redistribution of cations on octahedral. The coercivity increased from 15 Oe to 59 Oe by increasing the yttrium concentration. The initial permeability decreased from 110 to 35 at 1 MHz by the incorporation of yttrium and this was attributed to the smaller grains which may obstruct the domain wall movement and impede the domain wall motion. The magnetic loss factors of substituted samples exhibit decreasing behavior in the frequency range 1 kHz to 10 MHz. The smaller FMR line-width and reduced magnetic loss factor of the investigated samples suggest the possible use of these materials in high frequency applications. (C) 2015 Elsevier B.V. All rights reserved,