Synthesis of Fe/SiO2 and iron oxides/SiO2 nanocomposites by long-term ball milling
- Pozo Lopez, Gabriela del Valle
- Condo, Adriana Maria
- Urreta, Silvia Elena
- Silvetti, Silvia Patricia de Guadalupe
DOIAbstract
Iron oxide/SiO2 nanocomposites are synthesized by dry ball-milling a mixture of bcc Fe and α-quartz powders for prolonged times. A sequence of nanocomposites is obtained, with small magnetic particles dispersed in a non magnetic, amorphous matrix. The powders are characterized by X-ray diffraction and transmission electron microscopy. The magnetic hysteresis properties are investigated in the range 50-300 K. After 120 h milling, deformed, non-spherical, α-Fe nanocrystallites of about 10 nm in size and very few small (<10 nm) maghemite particles are found. At room temperature, iron particles are ferromagnetic and a large effective magnetic anisotropy is estimated, which is mainly attributed to surface effects. Between 160 and 200 h milling, ...
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