Mössbauer spectroscopy of 57Fe in α-Al2O3 following implantation of 57Mn*

Abstract

The valence state and annealing reactions of Mn/Fe in single crystalline α-Al 2 O 3 have been determined following low fluence (<10 12 cm −2 ) 60 keV implantations of 57 Mn + (T 1/2 = 1.5 min) and emission Mössbauer spectroscopy on the 57m Fe daughter nuclei in the temperature range from 110-700 K. At 110 K, most probe atoms are found in the Fe 2+ state in amorphous surroundings due to the implantation damage. A fraction of the Fe is found in cubic environment, possibly nano-precipitates of η-Al 2 O 3 . This site is found to disappear from the

Atomic‐Scale Magnetic Properties of Truly 3d‐Diluted ZnO

“…Our results are in accordance with those previously reported in Co and Gd implanted ZnO crystals at fl uences from 5 × 10 13 to 1 × 10 15 cm −2 (total maximum ion concentration of 0.2%), where the absence of room temperature ferromagnetism has been evidenced. [ 40 ] By conducting experiments similar to those reported here, no magnetic ordering has been detected in Mn/ Fe-implanted Al 2 O 3 , [ 41 ] MgO, [ 20 ] TiO 2 , [ 29 ] and SnO 2 [ 42 ] in the ultra-dilute regime (i.e., 10 −5 -10 −3 at%) as well.…”

Magnetism in iron implanted oxides: a status report

“…Upon Mn implantation again several components show up see Fig. 6 and Table 2 [14]. As described above for the case of MgO data were taken in zero field and with applied field of 0.3 T. The sextet has B Hf close to 50 T, again similar to the one observed in ZnO and MgO identifying this component as Fe 3+ .…”

“…The central part of the spectrum consists of an asymmetric doublet (Dam), indicative of an amorphous surrounding with IS compatible with 2+ which is still present at the highest temperature of 666 K, indicating large defect migration energies. A cubic component (S1) which possibly is a nano-precipitate of η-Al 2 O 3 is assigned in addition [14]. An analysis of the relaxation rate of the magnetic component as described for ZnO is included in Fig.…”

Observation of spin-lattice relaxations of dilute Fe3+ in MgO by Mössbauer spectroscopy

“…These spectral components are easily distinguishable in the Mössbauer spectra as they have intensity in the wings of the spectra for |v| > 4 mm/s. Such components have been reported in ZnO [1,2], MgO [3] and α-Al 2 O 3 [4]. The reasons for such a slow relaxation process are presumably a negligible spin-spin relaxation caused by the low concentration (<10 −4 at.…”