The Advanced Characterization and Nanostructuration of Materials (ACNM) group’s main scientific goal is to generate both fundamental and applied knowledge for the implementation of functional oxide materials in novel technologies as spintronics.
The group focuses on the preparation and advanced characterization of thin films and nanostructures of complex oxides with potential functional properties of interest for the development of magnetoelectronic devices with new and enhanced performances.
The main research line is focused on the use of the spin of electrons as a control variable for the implementation on spintronic devices. Additionally, resistive switching phenomena and self-assembling processes in functional oxides and preparation and characterization of magnetic nanoparticles for life sciences are also investigated.
Functional properties of magnetic oxide thin films are very often dependent on the microstructural features. In particular, double perovskite oxides are of interest because of their electric, magnetic, and elastic properties. However, these properties are strongly dependent on the ordered arrangement of cations in the double perovskite structure.
This year, group’s work has concentrated on the epitaxial growth of La2AMnO6 (A=Co, Ni) double perovskites by using both sputtering and polymer assisted deposition (PAD) techniques. Confirmation of the achievement of full Co/Mn cationic ordering was found by scanning transmission electron microscopy (STEM) measurements; EELS maps indicated the ordered occupancy of B– B′ sites by Co/Mn cations. As a result, optimal magnetic properties (Msat ≈ 6 μB /f.u. and Tc ≈ 230 K) are obtained. In the case of Ni/Mn full suppression of antisite defects is a little bit more difficult signaling to differences of ionic radius between Co/Mn and Ni/Mn. Nevertheless, La2NiMnO6 epitaxial thin films of excellent quality and antisite defects below 10 %, among the best in the literature, have been obtained.
Group’s work has also focused on reversible resistive switching (RS) phenomena, i.e. the change of resistance in a reversible manner between two stable states of well-defined resistance by applying voltage pulses, which has been proposed as an appealing solution for the development of nonvolatile memory devices. We have studied the local electrical properties, measured by conductive atomic force microscopy, of semimetallic SrIrO3 thin films demonstrating the appearance of an Anderson-type metal−insulator transition triggered by disorder and spatial localization due to film thickness reduction. For thin enough films (below ∼3 nm) samples are insulating with hysteretic I−V curves indicative of reversible resistive switching behavior between two states of clearly different resistance at room temperature.
Dynamic magnetic properties and spin pumping in polymer-assisted-deposited La0.92MnO3 thin films
Hailin Wang, Alberto Pomar, Sergi Martín-Rio, Carlos Frontera, Narcis Mestres and Benjamín Martínez
J. Mater. Chem. C, 7, 12633-12640, 2019
Resistive Switching in Semimetallic SrIrO3 Thin Films
Víctor Fuentes, Borislav Vasić, Zorica Konstantinović, Benjamín Martínez, Lluís Balcells and Alberto Pomar
ACS Appl. Electron. Mater., 1, 9, 1981–1988, 2019
Spontaneous cationic ordering in chemical-solution-grown La2CoMnO6 double perovskite thin films
Hailin Wang, Jaume Gazquez, Carlos Frontera, Matthew F. Chisholm, Alberto Pomar, Benjamin Martinez and Narcis Mestres
NPG Asia Materials, 11, 44, 2019
Trapping and electrical characterization of single core/shell iron-based nanoparticles in self-aligned nanogaps
Jacqueline Labra-Muñoz, Zorica Konstantinović, Lluis Balcells, Alberto Pomar, Herre S.J. van der Zant, Diana Dulić
Appl. Phys. Lett., 115, 063104, 2019
Nanoscale mechanical control of surface electrical properties of manganite films with magnetic nanoparticles
Borislav Vasić, Zorica Konstantinović, Elisa Pannunzio-Miner, Sergio Valencia, Radu Abrudan, Radoš Gajić, Alberto Pomar
Nanoscale Adv., 1, 1763-1771, 2019
Spontaneous in-flight assembly of magnetic nanoparticles into macroscopic chains
Lluis Balcells, Igor Stanković, Zorica Konstantinović, Aanchal Alagh, Victor Fuentes, Laura López-Mir, Judit Oró, Narcis Mestres, Carlos García, Alberto Pomar, Benjamín Martínez
Nanoscale, 11, 14194-14202, 2019
Non-stoichiometry Driven Ferromagnetism in Double Perovskite La2Ni1-xMn1+xO6 Insulating Thin Films
Monica Bernal-Salamanca, Zorica Konstantinović, Lluis Balcells, Elisa Pannunzio-Miner, Felip Sandiumenge, Laura Lopez-Mir, Bernat Bozzo, Javier Herrero-Martín, Alberto Pomar, Carlos Frontera, Benjamín Martínez
Cryst. Growth Des., 19, 5, 2765–2771, 2019
Low Temperature Superspin Glass Behavior in a Co/Ag Multilayer
E. Navarro, M. Alonso, A. Ruiz, C. Magen, U. Urdiroz, F. Cebollada, Ll. Balcells, B. Martínez , F. J.
Palomares and J. M. González
AIP Advances 9, 125327, 2019
Switching on superferromagnetism
A. Arora, L. C. Phillips, P. Nukala, M. Ben Hassine, A. A. Unal, B. Dkhi, Ll. Balcells, O. Iglesias, A. Barthelemy, F. Kronast, M. Bibes, S. Valencia
Physical Review Materials 3, 024403, 2019
Uptake of Sb(V) by Nano Fe3O4-Decorated Iron Oxy-Hydroxides
Konstantinos Simeonidis, Kyriaki Kalaitzidou, Efthimia Kaprara, Georgia Mitraka, Theopoula Asimakidou, Lluis Balcells, Manassis Mitrakas
Water 11, 181, 2019