MAGNETIC-PROPERTIES OF A SIO2-NA2O-FE2O3 GLASS AND GLASS-CERAMIC

A homogeneous SiO2-Na2O-Fe2O3 glass containing 4.6% Fe2O3 was prepared and devitrified to produce a glass ceramic containing the magnetic co mpound Na5Fe(SiO3)(4). The DC magnetic susceptibility measurements per formed on both samples have shown that the magnetic ion-ion interactio n is antiferromagnetic and is stronger in the crystallized sample. It was also shown that M versus H data at different temperatures do not c ollapse to a single curve in the M versus HIT representation, for eith er the glass or the heat treated sample. But the spread of the data is larger in the heat treated sample, further indicating a stronger inte raction in the crystalline sample. The M versus H curves for the glass sample were fitted with Brillouin function by keeping the total numbe r of magnetic ions constant and varying the proportion of ferrous ions until a best fit was achieved. The [Fe2+]/[Fe-total] ratio obtained f rom the fit is in good agreement with the value obtained from X-ray ph otoelectron spectroscopy (XPS) performed on the glass sample. (C) 1998 Elsevier Science B.V. All rights reserved.