INVESTIGADORES
ERRICO Leonardo Antonio
congresos y reuniones científicas
Título:
Ab-initio study of structural, electronic, and magnetic properties of magnetic impurities in rutile TiO2
Autor/es:
L. A. ERRICO, M. WEISSMANN Y M. RENTERÍA
Lugar:
Buenos Aires, Argentina
Reunión:
Workshop; At the Frontiers of Condensed Matter physics II; 2004
Resumen:
Integrating spin
functionality into otherwise nonmagnetic materials has become a highly
desirable goal in the last years. In particular, dilute magnetic impurities in
semiconductors and oxides produce novel materials appealing for spintronics and
optoelectronics (see, e.g., refs. [1-2] and other references therein). Magnetic
dopants in nonmagnetic solids are assumed to couple with the electronic states
of the host, but remaining magnetically active. While most of the dilute
magnetic semiconductors have Curie temperatures much lower than room temperature,
this is not so for Co-doped rutile and anatase TiO2 and rutile SnO2
[2], [3]. However, many questions remain regarding the precise location of Co
in the host lattice and the underlying microscopic mechanism of long-range
magnetic order.
In this contribution we
present a set of density-functional-theory-based calculations in the systems RxTi1-xO2
(R = Mn, Fe, Co, Ni). The calculations were performed with the WIEN97
implementation [4] of the full-potential linearized-augmented-plane-wave
(FP-LAPW) method, assuming that the magnetic impurities substitutionally
replace the Ti ions. The calculations were performed considering different
dilutions and distributions of the impurities. The effects of the structural
relaxations induced by the impurities in the host-lattice on the magnetic
properties and the tendencies to ferromagnetism or antiferromagnetism are
discussed and compared with previous calculations and experiments. Finally,
from the study of different distributions of the impurities in the host, we
calculate the exchange interaction parameters (J).
This research was
partially supported by CONICET, Fundación Antorchas, ANPCyT (PICT 03-03727),
Argentina, and TWAS, Italy.
References
[1] Z. Yang, G. Liu, and R.
Wu, Phys. Rev. B 67, R60402 (2003).
[2] J. Y. Kim, Phys. Rev.
Lett. 90, 17401 (2003).
[3] S. B. Ogale et al.,
Phys. Rev. Lett. 91, 77205 (2003).
[4] P.
Blaha, K. Schwarz, P. Dufek, and J. Luitz, Wien97, (K. Schwarz, Technische
Universtität Wien, Austria, 1999), ISBN
3-9501031-0-4.