Research Groups

RESEARCH UNIT: Magnetic Materials and Functional Oxides

Laboratory of Multifunctional Thin Films and Complex Structures (MULFOX)

The group has made real progress on epitaxial ferroelectric (HfZr)O2 films and disclosure of electroresistance mechanisms, controllable transparence window of conducting oxides (SrVO3) and photoresponsive 2DEGs that mimic synaptic spike-timing dependent plasticity.

The Laboratory of Multifunctional Thin Films and Complex Structures (MULFOX) focuses on the development and integration of new materials, especially nanometric oxide thin films, and the exploration of their use in photovoltaics, photonics, electronics, spintronics, data storage and computing. These broad and scientifically challenging objectives are currently major technological demands, as silicon-based electronics is reaching its limits and radically new and sustainable approaches are needed.

Specifically, current activities include: the search for disruptive approaches to materials and methods in photovoltaic conversion and transparent metals; development of materials and devices that, based on polar materials, may allow us to contribute to develop more efficient data storage and brain-inspired computing schemes; exploring data storage and data manipulation alternatives to current methods, by using non-dissipative currents or efficient plasmonic signals and integration of functional (magnetic and ferroelectric) materials in photonic devices.


  • Prof. Josep Fontcuberta - Research Professor
  • Dr. Lourdes Fàbrega - Tenured Scientist
  • Dr. Florencio Sánchez - Tenured Scientist
  • Dr. Gervasi Herranz - Tenured Scientist
  • Dr. Vassil Skumryev - ICREA Research Professor – UAB
  • Dr. Mikko Kataja - Postdoctoral Researcher
  • Dr. Ferran Macià - Postdoctoral Researcher
  • Dr. Ignasi Fina - Postdoctoral Researcher (Ramon y Cajal)
  • Tingfeng Song - PhD Researcher
  • Yunwei Sheng - PhD Researcher
  • Xiao Long - PhD Researcher
  • Milena Sulzbach - PhD Researcher
  • Mathieu Mirjolet - PhD Researcher
  • Yu Chen - PhD Researcher
  • Saul Estandía - PhD Researcher
  • Jiahui Jia - PhD Researcher

(a) Transparent highly conducting oxides, (b) antiferromagnetic materials for secure data storage, (c) polarization and ionic resistive switching mechanisms in Hf0.5Zr0.5O2 (HZO) films, (d) tuning ferroelectric properties of HZO films by substrate selection, (e) photoresponsive 2DEGs mimicking spike-timing dependent plasticity.


The group has focused on the development of epitaxial ferroelectric Hf0.5Zr0.5O2 thin films and on the identification of the role of substrates on the stabilization of the ferroelectric phase and the observed polarization. Coexisting polarization-related and ionic controlled electroresistance mechanisms and ways to control them have been identified as well as ferroelectric tunnel junctions in complementary resistive switching to mitigate sneak current leakage in data storage arrays.

The group has also focused on building on achievements of previous years related to the impact of ferroelastic domains and possible polar domain walls in SrTiO3, and its use to electrically control the magnetic properties of adjacent magnetic layers, now that they have shown that electric field can produce avalanches of ferroelastic domains.

The group has discovered persistent photoconductance in 2DEGS (LAO/STO), demonstrating that the associated changes of resistance mimic neuromorphic-like electric responses can be used to encode visual patterns imprinted as spatiotemporal modulations of persistent photoconductance, inspiring neuromorphic hybrid electronic/photonic systems.

Magnetic materials are pivotal in current large data storage. Spin currents and antiferromagnets have come to enrich this arena while looking for lower energy consumption and storing robustness, respectively. Mulfox members have authored invited review documents focused on the critical role of interfaces in spin mixing conductance, identifying challenges and opportunities and unraveling how phase-separation and strain in antiferromagnetic materials can be used as toggles to keep magnetic information. Rotational polarization topologies at the nanoscale were observed in BaTiO3/SrTiO3 superlattices grown on cubic SrTiO3(001) by means of aberration-corrected scanning transmission electron microscopy, reflecting that nominal tetragonal structure of BTO allows rotational polar textures. Finally, Mulfox members have chaired and contributed to the Roadmap of Oxide Electronics developed within an EU COST consortium.


Rotational Polarization Nanotopologies in BaTiO3/SrTiO3 Superlattices
S. Estandía, F. Sánchez, M.F. Chisholm, J. Gazquez
Nanoscale, 11, 21275, 2019

Giant topological Hall effect in correlated oxide thin films
L Vistoli, W Wang, A Sander, Q Zhu, B Casals, R Cichelero, A Barthélémy, S Fusil, G Herranz, S Valencia, R Abrudan, E Weschke, K Nakazawa, H Kohno, J Santamaria, W Wu, V Garcia & M Bibes
Nature Physics 15, 67–72, 2019

Asymmetric Resistive Switching Dynamics in BaTiO3 Tunnel Junctions
M Qian, I Fina, F Sánchez, and J Fontcuberta
Adv. Electron.Mater. 5, 1800407, 2019

Quantification of propagating and standing surface acoustic waves by stroboscopic X-ray photoemission electron microscopy
M. Foerster, N. Statuto, B. Casals, A. Hernández-Mínguez, S. Finizio, A. Mandziak, L. Aballe, J. M. Hernàndez Ferràs and F. Macià
Journal of Synchrotron Radiation, 26, 184-193, 2019

Growth Window of Ferroelectric Epitaxial Hf0.5Zr0.5O2 Thin Films
J. Lyu, I. Fina, R. Solanas, J. Fontcuberta, and F. Sanchez
ACS Appl. Electron. Mater. 1 (2), 220–228, 2019

Epitaxial Integration on Si(001) of Ferroelectric Hf0.5Zr0.5O2 Capacitors with High Retention and Endurance
J. Lyu, I. Fina, J. Fontcuberta, F. Sanchez
ACS Appl. Mater. Interfaces, 11 (6), 6224–6229, 2019

Complementary Resistive Switching Using Metal–FerroelectricMetal Tunnel Junctions
M. Qian, I. Fina, F. Sánchez, J. Fontcuberta
Small, 15, 1805042, 2019

High Carrier Mobility, Electrical Conductivity, and Optical Transmittance in Epitaxial SrVO3 Thin Films
M. Mirjolet, F. Sánchez, J. Fontcuberta
Adv. Funct. Materials, 1808432, 2019

Disclosing odd symmetry, strain driven magnetic response of Co on Pt/PMN-PT (011)
M. Foerster, I. Fina, S. Finizio, B. Casals, A. Mandziak, F. Fauthand, L. Aballe
J. Phys.: Condens. Matter. 31, 084003, 2019

Topochemical nitridation of Sr2FeMoO6
R. Ceravola, C. Frontera, J. Oro ́-Solé, A. P. Black, C. Ritter, I. Mata, E. Molins, J. Fontcuberta and A. Fuertes
Chem. Commun. 55, 3105, 2019

Gap suppression at a Lifshitz transition in a multi-condensate superconductor
G. Singh, A. Jouan, G. Herranz, M. Scigaj, F. Sánchez, L. Benfatto, S. Caprara, M. Grilli, G. Saiz, F. Couëdo, C. Feuillet-Palma, J. Lesueur & N. Bergeal
Nature Materials, 18, 948 – 954, 2019

Multiple magnetic droplet soliton modes
N. Statuto, C. Hahn, J. M. Hernàndez, A. D. Kent, and F. Macià
Physical Review B 99, 174436, 2019

Towards Oxide Electronics: a Roadmap
M. Coll, J. Fontcuberta, M. Althammer, M. Bibes, H. Boschker, A. Calleja, G. Cheng, M. Cuoco, R. Dittmann, B. Dkhil, I. El Baggari, M. Fanciulli, I. Fina, E. Fortunato, C. Frontera, S. Fujita, V. Garcia, S.T.B. Goennenwein, C.-G. Granqvist, J. Grollier, R. Gross, A. Hagfeldt, G. Herranz, K. Hono, E. Houwman, M. Huijben, A. Kalaboukhov, D.J. Keeblea, G. Koster, L.F. Kourkoutis, J. Levy, M. Lira-Cantu, J.L. MacManus-Driscoll, Jochen Mannhart, R. Martins, S. Menzel, T. Mikolajick, M. Napari, M.D. Nguyen, G. Niklasson, C. Paillardah, S. Panigrahi, G. Rijnders, F. Sánchez, P. Sanchis, S. Sanna, D.G. Schlom, U. Schroeder, K.M. Shen, A. Siemon, M. Spreitzer, H. Sukegawa, R. Tamayo, J. van den Brink, N. Pryds, F. Miletto Granozio
Applied Surface Science, 482, 1–93, 2019
Guest editors: M. Coll, J. Fontcuberta, N. Pryds and F. Miletto Granozio

Enhanced ferroelectricity in epitaxial Hf0.5Zr0.5O2 thin films integrated with Si(001) using SrTiO3 templates
J. Lyu, I. Fina, R. Bachelet, G. Saint-Girons, S. Estandıa, J. Gazquez, J. Fontcuberta, F. Sanchez
Appl. Phys. Lett. 114, 222901, 2019

Plasticity of Persistent Photoconductance of Amorphous LaAlO3/SrTiO3 Interfaces under Varying Illumination Conditions.
Y. Chen, B. Casals, G. Herranz
ACS Appl. Electron. Mater. 1, 810-816, 2019

Engineering Ferroelectric Hf0.5Zr0.5O2 Thin Films by Epitaxial Stress
S. Estandía, N. Dix, J. Gazquez, I. Fina, J. Lyu, M. F. Chisholm, J. Fontcuberta,  F. Sánchez
ACS Applied Electronic Materials, 1, 8, 1449-1457, 2019

On the Role of Interfaces on Spin Transport in Magnetic Insulator/Normal Metal Heterostructures
J. Fontcuberta,H. B. Vasili, J. Gàzquez, F. Casanova
Adv. Mater. Interfaces, 6, 1900475, 2019

Solid-State Synapses Modulated by Wavelength-Sensitive Temporal Correlations in Optic Sensory Inputs
Y. Chen, B. Casals, F. Sánchez, G. Herranz
ACS Appl. Electron. Mater. 1, 7, 1189-1197, 2019

Independent Tuning of Optical Transparency Window  and Electrical Properties of Epitaxial SrVO3 Thin Films  by Substrate Mismatch
M. Mirjolet, H. B. Vasili, L. López-Conesa, S. Estradé, F. Peiró, J. Santiso, F. Sánchez, P. Machado, P. Gargiani, M. Valvidares, J. Fontcuberta
Adv. Funct. Mater. 29, 1904238, 2019

Synergetic Electronic and Ionic Contributions to Electroresistance in Ferroelectric Capacitors
M. Qian, I. Fina, M. Cervo Sulzbach, F. Sánchez, J. Fontcuberta
Advanced Electronic Materials 5, 3, 1800646, 2019

Direct Reversible Magnetoelectric Coupling in a Ferroelectric/Ferromagnetic Structure Controlled by Series Resistance Engineering
S. González-Casal, I. Fina, F. Sánchez, J. Fontcuberta
ACS Appl. Electron. Mater. 1, 9, 1937-1944, 2019

Strain and voltage control of magnetic and electric properties of FeRh films
I. Fina, J. Fontcuberta
Journal of Physics D: Applied Physics, 53, 2, 2019

Unraveling Ferroelectric Polarization and Ionic Contributions to Electroresistance in Epitaxial Hf0.5Zr0.5O2 Tunnel Junctions
M. Cervo Sulzbach, S. Estandía, X. Long, J. Lyu, N. Dix, J. Gàzquez, M. F. Chisholm, F. Sánchez, I. Fina, J. Fontcuberta
Adv. Electron. Mater. 6, 1900852 (2020)

Electric-field-induced avalanches and glassiness of mobile ferroelastic twin domains in cryogenic SrTiO3
B. Casals, S. van Dijken, G. Herranz, E. K. H. Salje
Phys. Rev. Research 1, 032025(R), 2019

Spectral and Angle-Resolved Magneto-Optical Characterization of Photonic Nanostructures.
Kataja, M., Cichelero, R., Herranz, G.
J. Vis. Exp. (153), e60094, 2019.

Optical isolation in magnetoplasmonic diffraction gratings .
Rafael Cichelero, Mikko Kataja, Gervasi Herranz
Proceedings of SPIE, Volume 11090, Spintronics XII
; 1109039

Disentangling Highly Asymmetric Magnetoelectric Effects in Engineered Multiferroic Heterostructures . 
Enric Menéndez, Veronica Sireus, Alberto Quintana, Ignasi Fina, Blai Casals, Rafael Cichelero, Mikko Kataja, Massimiliano Stengel, Gervasi Herranz, Gustau Catalán, Maria Dolors Baró, Santiago Suriñach, and Jordi Sort. 
Phys. Rev. Applied 12, 014041, 2019.

Electronic and structural reconstructions of the polar (111) SrTiO3 surface.
X. Torrelles, G. Cantele, G. M. De Luca, R. Di Capua, J. Drnec, R. Felici, D. Ninno, G. Herranz, and M. Salluzzo
Phys. Rev. B. 99, 205421, 2019

Unexpected large transverse magneto-optic Kerr effect at quasi-normal incidence in magnetoplasmonic crystals.
Cichelero, M.A. Oskuei, M. Kataja, S.M. Hamidi, G. Herranz, 
Journal of Magnetism and Magnetic Materials 476, 54–58, 2019

Vehicle Classification System Based on Ferroelectric Materials
I Fina, X Martí, G Catalan
2019 IEEE International Symposium on Applications of Ferroelectrics (ISAF), Lausanne, Switzerland, 1-4, 2019

Band Gap Tuning of Solution-Processed Ferroelectric Perovskite BiFe1–xCoxO3 Thin Films
Pamela Machado, Mateusz Scigaj, Jaume Gazquez, Estel Rueda, Antonio Sánchez-Díaz, Ignasi Fina, Martí Gibert-Roca, Teresa Puig, Xavier Obradors, Mariano Campoy-Quiles, and Mariona Coll
Chemistry of Materials 1 (3), 947-954, 2019

Awards and Recognitions

  • Gervasi Herranz was promoted to Research Scientist (Investigador Científico CSIC)
  • Florencio Sánchez was promoted to Research Scientist (Investigador Científico CSIC)
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Web & Graphic Editor
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