الملخص الإنجليزي
Abstract :
Powders of cadmium oxide codoped with Gd and Al ions were synthesised by thermal de-composition method. The mass ratio of Al/Cd in powder form samples was maintained
constant, while the mass ratio of Gd/Cd was varied systematically. The final purpose of
the present study was to synthesis powders having appreciable room temperature
ferromagnetic (RT-FM) properties. To achieve this task, amounts from each synthesised
powder were treated in hydrogen atmosphere in order to study its effect on the physical
properties, especially the magnetic properties of the samples.
The X-ray fluorescence (XRF) and X-ray diffraction (XRD) measurements confirm the
purity of the as-prepared powders and the formation of a mono-phase nano-crystalline
structure. Thus, the Gd and Al ions incorporated into host CdO lattice formed
substitutional solid solutions (SSS). The magnetic properties of the as–prepared and
hydrogenated powders were investigated as a function of % Gd doping level. It was
observed that the magnetic behaviour of pure CdO transforms from diamagnetic to
paramagnetic with doping by Al and Gd ions. More importantly, it was found that the
treatment in hydrogen atmosphere stimulates the conversion of some CdO forming Cd
metal nano-grains, resulting in transformation to ferromagnetic behaviour. For
hydrogenated CdO powder doped with 3% Gd, the coercivity (Hc), remanence (Mr), and
saturation magnetization (Ms) were 195.9 Oe, 0.77 memu/g, 5.1memu/g, respectively.
Therefore, it was proved, for the first time, the possibility of manufacturing CdO with
stable RT-FM by doping and post treatment under hydrogen atmosphere, thus a new
potential candidate to be used as a dilute magnetic semiconductor (DMS).
