An active field of research of our group is that related to the double perovskites of general formula A₂(BB’)O₆, where A stands for an alkali-earth metal and B, B’ are transition metals of the first and second (or third) rows. The most representative example is Sr₂FeMoO₆, ferrimagnetic and half-metallic, which is considered, at present, among the most promising MR materials, given their high T_C and MR at low field.

Recently, we demonstrated that high pressure is a powerful tool to minimize the unwanted antisite Fe/Mo disordering: degrees of ordering close to 100% can be obtained by pressure treatments starting from partially disordered perovskites (70% order). Additionally, we have prepared, also under pressure, the perovskite Sr₂FeReO₆ and, adequately tuning the oxidizing/reducing conditions, a large number of novel oxides like Sr₂BUO₆ (B= Mn, Fe, Ni, Zn), A₂CrSbO₆ (A= Ca, Sr), Ba₂BSbO₆ (B= Fe, Co), Sr₂MReO₆ (M= Ni, Co, Zn), etc…

Besides the currently exploited ideas to improve the properties of interest, based upon cationic substitutions, we aim to develop more original ideas based upon changing the anionic sublattice, enhancing the covalence of the chemical bonds, through nitridation or flourination of the previously formed oxide, thus favouring the first-neighbour magnetic interactions and enhancing ferromagnetism.

Recent Publications

High-pressure synthesis of the double perovskite Sr₂FeMoO₆: increment of the cationic ordering and enhanced magnetic properties . Retuerto, M.; Martinez-Lope, M. J.; Garcia-Hernandez, M.; Alonso, J. A. JOURNAL OF PHYSICS-CONDENSED MATTER 21, 186003  (2009)

A Structural and Magnetic Study of the Series of Double Perovskites Ca₂Fe_1+xW_1-xO₆, Retuerto, M, Alonso, JA, Martinez-Lope, MJ, Garcia-Hernandez, M, Lopez, CA, Viola, MD, Pedregosa, JC, Fernandez-Diaz, MT, EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, 25,  3750- 3757 (2009)

Study of the valence state and electronic structure in Sr₂FeMO₆ (M = W,  Mo, Re and Sb) double perovskites, Retuerto, M,  Jimenez-Villacorta, F, Martinez-Lope, MJ, Huttel, Y, Roman, E, Fernandez-Diaz, MT, Alonso, JA, PHYSICAL CHEMISTRY CHEMICAL PHYSICS 12,  13616-13625 (2010).

Raman and infrared spectroscopy of Sr₂B’UO₆ (B ‘ = Ni; Co) double perovskites, Moreira, A. F. L.; Garcia-Flores, A. F.; Granado, E.; Massa, N. E.; Pinacca, R. M.; Pedregosa, J. C.; Carbonio, R. E.; Munoz, A.; Martinez-Lope, M. J.; Alonso, J. A.; del Campo, L.; Meneses, D. De Sousa; Echegut, P.,VIBRATIONAL SPECTROSCOPY 54,  142-147 (2010)

Enhancing Magnetic and Magnetotransport Properties by Topotactic   Reduction of the Sr2Fe1.33Mo0.66O6 Double Perovskite, Lopez, CA, Viola, MD, Pedregosa, JC, Alonso, JA,   Fernandez-Diaz, MT, EUROPEAN JOURNAL OF INORGANIC CHEMISTRY  26, 4110- 4120 (2010)

Crystallo-chemical evolution of the La₂ZnTiO₆ double perovskite upon reduction: A structural study, Aguadero, A.; Alonso, J. A.; Martinez-Lope, M. J.; Fernandez-Diaz, M. T., SOLID STATE SCIENCES 13,  13-18 (2011)