New Technological Project

“Microhilos Magnéticos para Sensores Magnetoelásticos”

A contract of Technological Support has been signed with the Universidad Pública de Navarra (Prof. J.I. Pérez de Landazábal) concerning the development of magnetic microwires as sensing elements for magnetoelastic sensors (2021). The project is supervised by M. Vazquez.

New technological project

Magnetic Microwire Research Project

A contract has been signed with the company Bartington Instrument Ltd., United Kingdom, to develop technologically advanced magnetic microwires (2021-2022). The project is supervised by M. Vazquez and R.P del Real.

New patent

“Magnetic microwires for energy-transporting biomedical applications”

US Patent Application Pub.No. US 2021/0101016 A1; Northeastern University, Boston and CSIC

Inventors: L.H. Lewis, R. P. del Real, M. Vazquez Villalabeitia and A.N. Koppes

Methods and devices including amorphous magnetic microwires are provided for biomedical energy transfer for diagnosis or therapy, to promote cellular growth, or to deliver pharmaceutical agents. Applications of the technology include sensors, actuators and therapeutic coatings and for increasing the amount, directionally, or length of nerve growth. The technology can also be utilized for nerve regeneration, hyperthermic treatment of tumors, vascular theranostics, probing and stimulating a nerve, sensing a biological condition, catheterization and micro-actuation.

This patent application is the result of a continuous collaboration of our GNMP group with the Northeastern University of Boston.

New article

“Evidence of Skyrmion-Tube Mediated Magnetization Reversal in Modulated Nanowires”

E. Berganza, J. Marqués-Marchán, C. Bran, M. Vazquez, A. Asenjo and M. Jaafar

 Materials 14 (2021) 5671

DOI://doi.org/10.3390/ma14195671

Magnetic nanowires, as individual building blocks for spintronic devices, constitute a well-suited model to design and study magnetization reversal processes, or to tackle fundamental questions, as the presence of topologically protected magnetization textures under particular conditions. Recently, a skyrmion-tube mediated magnetization reversal process was theoretically reported in diameter modulated cylindrical nanowires where a vortex nucleates at the end of the segments with larger diameter and propagates, resulting in a first switching of the nanowire core magnetization at small fields. Here, we show experimental evidence of the so-called Bloch skyrmion-tubes, using advanced Magnetic Force Microscopy modes to image the magnetization reversal process of FeCoCu diameter modulated nanowires. By monitoring the magnetic state during applied field sweeping, a detected drop of magnetic signal at a given critical field unveils the presence of a skyrmion-tube, due to mutually compensating stray field components.

This study is a collaboration between our GNMP group and the Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Germany and the Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), and the Instituto Nicolás Cabrera, at the Universidad Autónoma de Madrid.

New article

“Stochastic vs. deterministic magnetic coding in designed cylindrical nanowires for 3D magnetic networks”

C. Bran, E. Saugar, J.A. Fernandez-Roldan, R.P. del Real, A. Asenjo, L. Aballe, M. Foerster, A. Fraile Rodríguez, E.M. Palmero, M. Vazquez and O. Chubykalo-Fesenko

Nanoscale 13 (2021) 12587

DOI: 10.1039/d1nr02337c

 

Advances in cylindrical nanowires for 3D information technologies profit from intrinsic curvature that introduces significant differences with regards to planar systems. A model is proposed to control the stochastic and deterministic coding of remanent 3D complex vortex configurations in designed multilayered (magnetic/non-magnetic) cylindrical nanowires. This concept, introduced by micromagnetic simulations, is experimentally confirmed by magnetic imaging in FeCo/Cu multilayered nanowires. The control over the random/deterministic vortex states configurations is achieved by a suitable geometrical interface tilting of almost non-interacting FeCo segments with respect to the nanowire axis, together with the relative orientation of the perpendicular magnetic field. The proper design of the segments’ geometry (e.g. tilting) in cylindrical nanowires opens multiple opportunities for advanced nanotechnologies in 3D magnetic networks.

This work has been performed in collaboration between our GNMP group at ICMM/CSIC with ALBA Synchrotron Light Facility, CELLS, Barcelona, the Departament de Física de la Matèria Condensada, Universitat de Barcelona and the Group of Permanent Magnets and Applications, IMDEA Nanoscience, Madrid. It has been supported by the Spanish Ministry of Science and Innovation under Projects MAT2016-76824-C3-1-R, PID2019-108075RB-C31/AEI /10.13039/501100011033 and PGC2018-097789-B-I00 and the Regional Government of Madrid under Project S2018/NMT-4321 NANOMAGCOST-CM.

New Review Article

“Matteucci Effect and Single Domain Wall Propagation in Bistable Microwire under Applied Torsion”

 A. Jiménez, E. Calle, J.A. Fernandez-Roldan, R.P. del Real, R. Varga and M. Vázquez

Phys. Status Solidi A 2021, 2100284  

DOI: 10.1002/pssa.202100284

Systematic experimental results on the Matteucci effect in torsioned magnetostrictive FeSiB microwire are introduced observed during the propagation of a single domain wall (DW) under the action of axial driving magnetic field, Hdr. The Matteucci electromotive force (emf) is associated with depinning and annihilation of the DW. The emf amplitude is proportional to the DW velocity and the time derivative of the azimuthal magnetization, tailored by applied torsion. The clockwise/counterclockwise applied torsion dependence of Matteucci emf and DW velocity are experimentally determined for parallel and antiparallel Hdr. Asymmetric behaviors are observed for both, the sense of applied torsion and the direction of Hdr. The experimental data are discussed in terms of the magnetoelastic anisotropy introduced by torsion. Through analysis of the DW dynamics, such asymmetric behaviors are interpreted as a magnetochiral effect derived from the change of chirality of the propagating wall.

This Review Article is included in the special issue to celebrate the 60th anniversary of Physica Status Solidi, and it is a collaboration between our GNMP group and the Centre of Progressive Materials, P.J. Safarik University Kosiçe, Slovakia. It was supported by the Regional Government of Madrid under project S2018/NMT-4321 NANOMAGCOST-CM.

New article

Field tunable three-dimensional magnetic nanotextures in cobalt-nickel nanowires”

I.M. Andersen, D. Wolf, L.A. Rodriguez, A. Lubk, D. Oliveros, C. Bran, T. Niermann, U.K. Rößler, M. Vazquez, C. Gatel and E. Snoeck

 Phys. Rev. Research 3 (2021) 033085

DOI: doi.org/10.1103/PhysRevResearch.3.033085

 

Cylindrical magnetic nanowires with large transversal magnetocrystalline anisotropy sustain nontrivial magnetic configurations resulting from the interplay of spatial confinement, exchange and anisotropies. Holographic vector-field electron tomography is employed to reconstruct the remanent magnetic states in CoNi nanowires with 10 nm resolution in 3D, with a particular focus on domain walls between remanent states and ubiquitous real-structure effects stemming from irregular morphology and anisotropy variations.

By tuning the applied magnetic field direction, both longitudinal and transverse multivortex states of different chiralities and peculiar 3D features such as shifted vortex cores are stabilized. The chiral domain wall between the longitudinal vortices of opposite chiralities exhibits a complex 3D shape characterized by a push out of the central vortex line and a gain in exchange and anisotropy energy. Exploiting these peculiar 3D spin configurations and their solitonic inhomogeneities is expected to improve magnetization switching in future spintronics, such as power-saving magnetic memory and logic applications

This work is the result of the international collaboration between our GNMP group, ICMM/CSIC, with the Centre d’Élaboration de Matériaux et d’Etudes Structurales, CNRS, Toulouse, and the Leibniz Institute for Solid State and Materials Research, IFW Dresden. It has been supported by Spanish MINECO under project PID2019-108075RBC31, and by the Regional Government of Madrid under Project S2018/NMT-4321 NANOMAGCOSTCM.

New people in the group

Joao Filipe Pinto de Queiros Fradet has been awarded with a predoc grant FPI linked to the National Project «3D magnetism in cylindrical geometry for energy efficient emergent technologies». He will study  the movement of magnetic domain-walls induced by electric current and thermal gradients on magnetic nanowires. To that aim, characterization techniques such as MFM and  XMCD-PEEM microscopies will be employed in combination with micromagnetic simulations. Nanofabrication methods will be developed employing physical and electrochemical techniques, such as electrodeposition onto nanoporous alumina templates and sputtering.

New people in the group

Felipe Tejo, from Chile, has been awarded with a postdoc grant «ANID-PFCHA/Postdoctorado Becas Chile 74200122» and he will be with us until June 2022. Using magnetic simulations he will study magnetic properties of skyrmions and Bloch points.