Mössbauer characterization of <sup>119</sup>Sn<sup>4+</sup> Dopant ions in the antiferromagnetic ilmenite NiTiO<sub>3</sub>
Language
en
Article de revue
This item was published in
Solid State Communications. 2009, vol. 149, n° 37-38, p. 1535-1538
Elsevier
English Abstract
Magnetic hyperfine splitting of the <sup>119</sup>Sn<sup>4+</sup> nuclear levels in the antiferromagnetic NiTiO<sub>3</sub> was for the first time observed using the Mössbauer effect. For the majority of the <sup>119</su ...Read more >
Magnetic hyperfine splitting of the <sup>119</sup>Sn<sup>4+</sup> nuclear levels in the antiferromagnetic NiTiO<sub>3</sub> was for the first time observed using the Mössbauer effect. For the majority of the <sup>119</sup>Sn<sup>4+</sup> dopant ions, the saturation value of the transferred hyperfine field (at 4.2 K, H = 5.25 T) is found to be equal to that previously reported for <sup>119</sup>Sn<sup>4+ </sup>in the antiferromagnetic MnTi0<sub>3</sub>. This finding shows that in both ilmenites the spin polarization of Sn<sup>4+</sup> is produced by the divalent cation half-filled e<sup>2</sup><sub>g</sub> orbitals involved in interlayer superexchange interactions and implies the location of the dopant within titanium (111) layers. The principal V<sub>zz</sub> component of the EFG at the Sn<sup>4+</sup> site in NiTiO<sub>3</sub> is found to have a positive sign and be aligned along the [111] axis, as it was the case for Sn<sup>4+</sup> in MnTiO<sub>3</sub>. Lattice-sum calculations on the basis of a simple ionic point-charge model, lead to an erroneous result (in either titanate the sign of V<sub>zz</sub> on the Ti<sup>4+</sup> site would be negative) and thus demonstrate their failure in identifying the Sn sites.Read less <
English Keywords
Antiferromagnetic materials
Nickel titanates
Point charge approximation
Electric field gradients
Superexchange interactions
Spin polarization
Hyperfine magnetic field
Hyperfine splitting
Doping
Mössbauer effect
Origin
Hal imported