Room temperature magnetic ordering in very dilute Iron doped with and without selenium substitutions in antimony matrix

Abstract

Mossbauer spectroscopy is one of the very sensitive tools to study the hyperfine interactions in alloys and compounds. The interaction of the probe with the local environment gives information like spin state, coordination number, magnetic and quadrupole interaction etc. In the present study, 57Fe Mossbauer spectroscopy was used to study the hyperfine interaction of the FexSb1-x-ySey bulk alloy with very dilute quantity of Fe, x = 0.002. The measurements were done at room temperature. Keeping the amount of Fe constant in the bulk alloy at x = 0.002, the concentration of Se was varied from y = 0.000, 0.004, 0.016 to 0.048. Additionally, to see the effect of extremely low concentration of Fe in Sb matrix alone, a sample with Fe concentration of 0.0015 was prepared without any Se substitution in Sb. The structural study was done using X-ray diffraction technique. Neutron depolarization study was done to see if clusters of Fe were present in the samples. The XRD spectra showed Sb peaks with no other compound phases. From Mossbauer spectroscopy, at y = 0.000, x = 0.002 one magnetic site (site A) with hyperfine magnetic field of ~312 kOe was observed. When the concentration of Fe was further reduced to x = 0.0015, there was no change in the hyperfine magnetic field of ~312 kOe. On introduction of Se into the system, we observed two magnetic sites (A and B). The value of hyperfine magnetic field (HMF) for both the sites (A and B) decreases with increases in Se concentration. At higher concentration of Se (y = 0.048) an additional nonmagnetic site (site C) with quadrupole splitting of 0.51 mm/s was also observed.