We studied the effect of Argon (Ar) ion irradiation on Fe-Al2O3 nanogranular thin film. X-ray diffraction (XRD) patterns show that the ion dose might promote the growth of the Fe2O3 phase from an amorphous phase to a crystalline phase. The magnetic and magnetoresistance properties were investigated using a vibrating sample magnetometer (VSM) and a four point probe (FPP). The results suggest that percolation concentration occurred at the 0.55 Fe volume fraction and with a maximum magnetoresistance (MR) ratio of 3%. The present MR ratio was lower than that of previous results, which might be related to the existence of the α-Fe2O3 phase promoted by Ar ion irradiation. CEMS spectra show ion irradiation induces changes from superparamagnetic characteristics to ferromagnetic ones, which indicates the spherical growth of Fe particles in the Al2O3 matrix.

Bahasa Abstract

Pengaruh Iradiasi Ion Argon pada Sifat Magnetik Film Nano Granular Fe-Al2O3. Kami telah mempelajari pengaruh iradiasi ion Argon (Ar) pada film tipis Nanogranular Fe-Al2O3. Dari pola difraksi sinar X (XRD) diketahui peningkatan dosis ion menyebabkan tumbuhnya fasa amorf Fe2O3 menjadi fasa kristalin. Sifat magnetik dari film telah diperiksa dengan alat vibrating sample magnetometer (VSM) dan four point probe (FPP). Hasil pengukuran menunjukkan bahwa konsentrasi perkolasi terjadi pada fraksi volume 0.55 Fe dimana nisbah Magnetoresistance (MR) bahan bernilai 3%. Pada pengukuran MR kali ini terukur lebih rendah dibandingkan sebelumnya yang dapat dikaitkan dengan keberadaan fasa α-Fe2O3 akibat pengaruh iradiasi ion Argon. Spektrum conversion electron Mossbauer spectroscopy (CEMS) memperlihatkan bahwa iradiasi ion telah menginduksi perubahan sifat superparamagnetik film menjadi feromagnetik yang diindikasikan oleh tumbuhnya partikel spherical Fe di dalam matrik Al2O3.


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