Itinerant-Electron Ferromagnetism in a Titanium-Rich Magnesium Titanate Ilmenite Solid Solution

作者：Fujioka Y^*; Frantti J; Nieminen R M

来源：Journal of Physical Chemistry C, 2011, 115(5): 1457-1463.

DOI：10.1021/jp107698j

Magnetization hysteresis loops and magnetic susceptibility were measured from Mg(0.9)Ti(1.1)O(3) and Mg(0.88)-Ti(1.12)O(3) samples. The hysteresis loops revealed that the ferromagnetic transition occurs at or below 260 K. The magnetization did not reach saturation up to 70 kOe at 5 K. In contrast, stoichiometric MgTiO(3), consisting of closed. shell ions, does not exhibit magnetic ordering. Combined magnetic susceptibility measurements, X-ray diffraction, X-ray photoelectron spectroscopy, and spin-polarized density-functional theory computations show that the ferromagnetism is due to the conduction electrons, which are responsible for the semimetallic nature of the titanium-rich magnesium titanate Mg(1-x)Ti(1+x)O(3) solid solution. Excess Ti at the Mg-O cation layer results in a partially occupied band at the conduction band edge. This in turn shows that the magnetic properties can be controlled by a transition metal element substitution in a cation layer, which is a technological advantage.

• 出版日期2011-2-10