Person: Martínez De Irujo Labalde, Xabier
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First Name
Xabier
Last Name
Martínez De Irujo Labalde
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Química Inorgánica
Area
Química Inorgánica
Identifiers
5 results
Search Results
Now showing 1 - 5 of 5
Item Structural Ordering Supremacy on the Oxygen Reduction Reaction of Layered Iron-Perovskites(Inorganic Chemistry, 2020) Martínez De Irujo Labalde, Xabier; Marín Gamero, Rafael; Urones Garrote, Esteban; García Martín, Susana; ACS PublicationsItem Multiferroism induced by spontaneous structural ordering in antiferromagnetic iron perovskites(Chemistry of Materials, 2019) Martínez De Irujo Labalde, Xabier; Goto, Masato; Urones-Garrote, Esteban; Amador, Ulises; Ritter, Clemens; Amano Patino, Midori ; Koedtruad, Anucha; Tan, Zhenhong; Shimakawa, Yuichi; García Martín, SusanaRoom-temperature multiferroism in polycrystalline antiferromagnetic Fe perovskites is reported for the first time. In the perovskite-type oxides RE1.2Ba1.2Ca0.6Fe3O8 (RE = Gd, Tb), the interplay of layered ordering of Gd(Tb), Ba, and Ca atoms with the ordering of FeO4-tetrahedra (T) and FeO6-octahedra (O) results in a polar crystal structure. The layered structure consists of the stacking sequence of RE/Ca-RE/Ca-Ba-RE/Ca layers in combination with the TOOT sequence in a unit cell. A polar moment of 33.0 μC/cm2 for the Gd-oxide (23.2 μC/cm2 for the Tb one) is determined from the displacements of the cations, mainly Fe, and oxygen atoms along the b-axis. These oxides present antiferromagnetic ordering doubling the c-axis, and the magnetic structure in the Tb-compound remains up to 690 K, which is one of the highest transition temperatures reported in Fe perovskites.Item Complex modulation of the crystal structure of a layered perovskite. A promising solid-oxide-fuelcell cathode(Journal of Materials Chemistry A, 2016) Martínez De Irujo Labalde, Xabier; Muñoz Gil, Daniel; Urones Garrote, Esteban; Ávila Brande, David; García Martín, SusanaLayered-type perovskites have been the focus of research in the last few years due to their outstanding properties as solid oxide fuel cell oxygen electrodes. The synthesis of a new (GdBa)0.8Ca0.4Co0.6Fe1.4O6-d layered perovskite as a single phase as well as the crystal structure determination and catalytic activity for oxygen reduction is reported. Highly advanced methods of transmission electron microscopy have been used for structure determination at atomic resolution. The oxide shows a complex modulation of the crystal structure associated with layered-type ordering of the Gd, Ba and Ca atoms in combination with formation of different coordination polyhedra of the Fe and Co atoms. Location of the anion vacancies within particular highly ion-conducting layers of the crystal structure has been achieved by phase image reconstruction. This material exhibits excellent electrochemical behaviour and thermal stability for use as an air electrode in IT-SOFCs.Item YBaCuO-type perovskites as potential air electrodes for SOFCs. The case of YSr2Cu2FeO7+δ(Journal of Materials Chemistry A, 2021) López Paz, Sara Almudena; Marín Gamero, Rafael; Martínez De Irujo Labalde, Xabier; Sánchez Marcos, Jorge; Perez Coll, Domingo; Alario y Franco, Miguel Ángel; García Martín, SusanaThe electrochemical properties of YSr2Cu2FeO7+d with YBaCuO-type structure have been studied. The temperature dependent oxygen content of this oxide has a marked influence on its p-type conducting behavior, since topochemical oxygen release occurs on heating above 673 K while reversible oxygen uptake takes place on cooling. Mixed valence Fe3+/Fe4+ and Cu2+/Cu3+ in combination with anion vacancies within the oxygen-sublattice suggest mixed (electronic and ionic) conductivity in this oxide. Electrochemical measurements indicate that YSr2Cu2FeO7+d shows high oxygen reduction reaction activity at intermediate temperatures, revealing its potential applications as an air electrode in SOFCs.Item 3D to 2D Magnetic Ordering of Fe3+ Oxides Induced by Their Layered Perovskite Structure(Inorganic Chemistry, 2021) García Martín, Susana; Martínez De Irujo Labalde, Xabier; Amador, Ulises; Ritter, Clemens; Goto, Masato; Patino, Midori Amano; Shimakawa, YuichiThe antiferromagnetic behavior of Fe3+ oxides of composition RE1.2Ba1.2Ca0.6Fe3O8, RE2.2Ba3.2Ca2.6Fe8O21, and REBa2Ca2Fe5O13 (RE = Gd, Tb) is highly influenced by the type of oxygen polyhedron around the Fe3+ cations and their ordering, which is coupled with the layered RE/Ba/Ca arrangement within the perovskite-related structure. Determination of the magnetic structures reveals different magnetic moments associated with Fe3+ spins in the different oxygen polyhedra (octahedron, tetrahedron, and square pyramid). The structural aspects impact on the strength of the Fe-O-Fe superexchange interactions and, therefore, on the Neel temperature ( ́ TN) of the compounds. The oxides present an interesting transition from three-dimensional (3D) to two-dimensional (2D) magnetic behavior above TN. The 2D magnetic interactions are stronger within the FeO6 octahedra layers than in the FeO4 tetrahedra layers.