DE PAOLI JUAN MARTÍN
Congresos y reuniones científicas
Título:
Structural magnetic and electric characterization of Sr3M2ReO9 (M= Cr, Fe).
Autor/es:
E. V. PANNUNZIO-MINER; J. M. DE PAOLI; R. D. SÁNCHEZ; R. E. CARBONIO
Lugar:
Buenos Aires, Argentina.
Reunión:
Congreso; At the Frontiers of Condensed Matter III.; 2006
Resumen:
Structural magnetic and electriccharacterization of Sr3M2ReO9 (M= Cr, Fe).
Pannunzio-Miner, E. V.1, De Paoli, J. M.2, Sanchez, R. D.2, and Carbonio, R. E.1.
1 Depto. Fisicoquımica, Facultad de Ciencias Qu´ımicas, U. N. de Cordoba.
2 Centro Atomico Bariloche-CNEA.
The search of new materials with colossal magnetoresistant (CMR) includes some members of the family of double perovskites A2BB’O6 (A= alkali earths and B, B’= transition metals). These, as an alternative to perovskite manganites, have been proposed as half-metallic ferromagnets with TC’s well above room temperature. These transition metals oxides have a ”double” crystalline structure because they have, in an ideal order, the M ions alternated in two different B site. The interest in this family was triggered by a report on Sr2FeMoO6, demonstrating that in the electronic structure only minority spins are present at the Fermi level. This material exhibits magnetoresistance (MR) at room temperature, which has also been observed for double perovskites containing other transition metals than Mo, such as A2FeReO6 (A= Ca, Sr, Ba). In the present work we present magnetoresistance, hysteresis loops, magnetization and electrical resistivity as a function of temperature from a new chemical composition of these oxides: Sr3M2ReO9 with M= Cr or Fe. Their crystallographic formula can be written like Sr2[(M) 2a (M,Re) 2b]O6, being the site 2b occupied by 1/3 of M ions and 2/3
by Re ions, turning it one in a double Perovskite with intrinsic disorder in the 2a and 2b crystallographic B sites.
Pannunzio-Miner, E. V.1, De Paoli, J. M.2, Sanchez, R. D.2, and Carbonio, R. E.1.
1 Depto. Fisicoquımica, Facultad de Ciencias Qu´ımicas, U. N. de Cordoba.
2 Centro Atomico Bariloche-CNEA.
The search of new materials with colossal magnetoresistant (CMR) includes some members of the family of double perovskites A2BB’O6 (A= alkali earths and B, B’= transition metals). These, as an alternative to perovskite manganites, have been proposed as half-metallic ferromagnets with TC’s well above room temperature. These transition metals oxides have a ”double” crystalline structure because they have, in an ideal order, the M ions alternated in two different B site. The interest in this family was triggered by a report on Sr2FeMoO6, demonstrating that in the electronic structure only minority spins are present at the Fermi level. This material exhibits magnetoresistance (MR) at room temperature, which has also been observed for double perovskites containing other transition metals than Mo, such as A2FeReO6 (A= Ca, Sr, Ba). In the present work we present magnetoresistance, hysteresis loops, magnetization and electrical resistivity as a function of temperature from a new chemical composition of these oxides: Sr3M2ReO9 with M= Cr or Fe. Their crystallographic formula can be written like Sr2[(M) 2a (M,Re) 2b]O6, being the site 2b occupied by 1/3 of M ions and 2/3
by Re ions, turning it one in a double Perovskite with intrinsic disorder in the 2a and 2b crystallographic B sites.
