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Basini M, Pancaldi M, Wehinger B, Udina M, Unikandanunni V, Tadano T, Hoffmann MC, Balatsky AV, Bonetti S. Terahertz electric-field-driven dynamical multiferroicity in SrTiO 3. Nature 2024; 628:534-539. [PMID: 38600387 PMCID: PMC11023939 DOI: 10.1038/s41586-024-07175-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 02/07/2024] [Indexed: 04/12/2024]
Abstract
The emergence of collective order in matter is among the most fundamental and intriguing phenomena in physics. In recent years, the dynamical control and creation of novel ordered states of matter not accessible in thermodynamic equilibrium is receiving much attention1-6. The theoretical concept of dynamical multiferroicity has been introduced to describe the emergence of magnetization due to time-dependent electric polarization in non-ferromagnetic materials7,8. In simple terms, the coherent rotating motion of the ions in a crystal induces a magnetic moment along the axis of rotation. Here we provide experimental evidence of room-temperature magnetization in the archetypal paraelectric perovskite SrTiO3 due to this mechanism. We resonantly drive the infrared-active soft phonon mode with an intense circularly polarized terahertz electric field and detect the time-resolved magneto-optical Kerr effect. A simple model, which includes two coupled nonlinear oscillators whose forces and couplings are derived with ab initio calculations using self-consistent phonon theory at a finite temperature9, reproduces qualitatively our experimental observations. A quantitatively correct magnitude was obtained for the effect by also considering the phonon analogue of the reciprocal of the Einstein-de Haas effect, which is also called the Barnett effect, in which the total angular momentum from the phonon order is transferred to the electronic one. Our findings show a new path for the control of magnetism, for example, for ultrafast magnetic switches, by coherently controlling the lattice vibrations with light.
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Affiliation(s)
- M Basini
- Department of Physics, Stockholm University, Stockholm, Sweden
| | - M Pancaldi
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, Venice, Italy
- Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
| | - B Wehinger
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, Venice, Italy
- European Synchrotron Radiation Facility, Grenoble, France
| | - M Udina
- Department of Physics and ISC-CNR, 'Sapienza' University of Rome, Rome, Italy
| | - V Unikandanunni
- Department of Physics, Stockholm University, Stockholm, Sweden
| | - T Tadano
- Research Center for Magnetic and Spintronic Materials, National Institute for Materials Science, Tsukuba, Japan
| | - M C Hoffmann
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - A V Balatsky
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, Venice, Italy
- NORDITA, Stockholm, Sweden
- Department of Physics, University of Connecticut, Storrs, CT, USA
- Rara Foundation - Sustainable Materials and Technologies, Venice, Italy
| | - S Bonetti
- Department of Physics, Stockholm University, Stockholm, Sweden.
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, Venice, Italy.
- Rara Foundation - Sustainable Materials and Technologies, Venice, Italy.
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Bossini D, Pancaldi M, Soumah L, Basini M, Mertens F, Cinchetti M, Satoh T, Gomonay O, Bonetti S. Ultrafast Amplification and Nonlinear Magnetoelastic Coupling of Coherent Magnon Modes in an Antiferromagnet. Phys Rev Lett 2021; 127:077202. [PMID: 34459640 DOI: 10.1103/physrevlett.127.077202] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 05/22/2021] [Accepted: 06/24/2021] [Indexed: 06/13/2023]
Abstract
We investigate the role of domain walls in the ultrafast magnon dynamics of an antiferromagnetic NiO single crystal in a pump-probe experiment with variable pump photon energy. Analyzing the amplitude of the energy-dependent photoinduced ultrafast spin dynamics, we detect a yet unreported coupling between the material's characteristic terahertz- and gigahertz-magnon modes. We explain this unexpected coupling between two orthogonal eigenstates of the corresponding Hamiltonian by modeling the magnetoelastic interaction between spins in different domains. We find that such interaction, in the nonlinear regime, couples the two different magnon modes via the domain walls and it can be optically exploited via the exciton-magnon resonance.
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Affiliation(s)
- D Bossini
- Department of Physics and Center for Applied Photonics, University of Konstanz, D-78457 Konstanz, Germany
| | - M Pancaldi
- Department of Physics, Stockholm University, 106 91 Stockholm, Sweden
| | - L Soumah
- Department of Physics, Stockholm University, 106 91 Stockholm, Sweden
| | - M Basini
- Department of Physics, Stockholm University, 106 91 Stockholm, Sweden
| | - F Mertens
- Experimentelle Physik VI, Technische Universität Dortmund, Otto-Hahn Straße 4, 44227 Dortmund, Germany
| | - M Cinchetti
- Experimentelle Physik VI, Technische Universität Dortmund, Otto-Hahn Straße 4, 44227 Dortmund, Germany
| | - T Satoh
- Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551, Japan
| | - O Gomonay
- Institut für Physik, Johannes Gutenberg Universität Mainz, D-55099 Mainz, Germany
| | - S Bonetti
- Department of Physics, Stockholm University, 106 91 Stockholm, Sweden
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, 30172 Venezia-Mestre, Italy
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Arosio P, Basini M, Barbaglia A, Piñol R, Murillo JL, Millán A, Lascialfari A. Effect of Spin Clustering on Basic and Relaxometric Properties of Magnetic Nanoparticles. J Nanosci Nanotechnol 2019; 19:2950-2962. [PMID: 30501805 DOI: 10.1166/jnn.2019.16019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
An increasing awareness about novel medical applications of smaller, inorganic-based nanoparticles, possessing unique properties at the nanoscale, has led to a burst of research activities in the development of "nanoprobes" for diagnostic medicine and agents for novel, externally activated therapies. In this research field magnetic nanoparticles are prominent due to fundamental peculiar properties particularly appealing for their use in materials and biomedical applications. Aiming to study the relationship between the topology of the magnetic nanoparticles and their efficacy as MRI contrast agents (relaxometric properties), we prepared three different stable colloidal suspension (ferrofluid) of magnetic nanobeads (MNBs) constituted by a discrete number of maghemite nanoparticles, arranged in disordered clusters or ordered in a polymeric matrix. An accurate morpho-dimensional and magnetic characterization displays the close correlation between the magnetic fundamental properties and the topology of our spin systems. The NMR relaxometry profiles confirmed the nature of the physical mechanisms inducing the increase of nuclear relaxation rates at low (magnetic anisotropy) and high (Curie relaxation) magnetic fields. Moreover the transverse relaxivity (r₂) values for all the MNBs are higher than those of common contrast agents and the differences between the three MNBs are suggested to be due to the spin topology effect.
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Affiliation(s)
- P Arosio
- Dipartimento di Fisica and INSTM, Università degli Studi di Milano and INSTM Milano Unit, Milano, 20133, Italy
| | - M Basini
- Dipartimento di Fisica and INSTM, Università degli Studi di Milano and INSTM Milano Unit, Milano, 20133, Italy
| | - A Barbaglia
- Italian Institute of Technology (IIT), Genova, Italy and Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, 16163, Italy
| | - R Piñol
- Departamento de Fisica de la Materia Condensada, Facultad de Ciencias and Instituto de Ciencia de Materiales de Aragón, CSIC Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - J L Murillo
- Departamento de Fisica de la Materia Condensada, Facultad de Ciencias and Instituto de Ciencia de Materiales de Aragón, CSIC Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - A Millán
- Departamento de Fisica de la Materia Condensada, Facultad de Ciencias and Instituto de Ciencia de Materiales de Aragón, CSIC Universidad de Zaragoza, 50009 Zaragoza, Spain
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Basini M, Orlando T, Arosio P, Casula MF, Espa D, Murgia S, Sangregorio C, Innocenti C, Lascialfari A. Local spin dynamics of iron oxide magnetic nanoparticles dispersed in different solvents with variable size and shape: A 1H NMR study. J Chem Phys 2017; 146:034703. [DOI: 10.1063/1.4973979] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- M. Basini
- Dipartimento di Fisica and INSTM, Università degli Studi di Milano, Milano, Italy
| | - T. Orlando
- EPR Research Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - P. Arosio
- Dipartimento di Fisica and INSTM, Università degli Studi di Milano, Milano, Italy
| | - M. F. Casula
- Dipartimento di Scienze Chimiche e Geologiche and INSTM, Università di Cagliari, Monserrato, Italy
| | - D. Espa
- Dipartimento di Scienze Chimiche e Geologiche and INSTM, Università di Cagliari, Monserrato, Italy
| | - S. Murgia
- Dipartimento di Scienze Chimiche e Geologiche and INSTM, Università di Cagliari, Monserrato, Italy
| | | | - C. Innocenti
- Dipartimento di Chimica and INSTM, Università degli studi di Firenze, Sesto Fiorentino, Italy
| | - A. Lascialfari
- Dipartimento di Fisica and INSTM, Università degli Studi di Milano, Milano, Italy
- Istituto di Nano scienze, CNR-S3, Modena, Italy
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Gossuin Y, Orlando T, Basini M, Henrard D, Lascialfari A, Mattea C, Stapf S, Vuong QL. NMR relaxation induced by iron oxide particles: testing theoretical models. Nanotechnology 2016; 27:155706. [PMID: 26933908 DOI: 10.1088/0957-4484/27/15/155706] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Superparamagnetic iron oxide particles find their main application as contrast agents for cellular and molecular magnetic resonance imaging. The contrast they bring is due to the shortening of the transverse relaxation time T 2 of water protons. In order to understand their influence on proton relaxation, different theoretical relaxation models have been developed, each of them presenting a certain validity domain, which depends on the particle characteristics and proton dynamics. The validation of these models is crucial since they allow for predicting the ideal particle characteristics for obtaining the best contrast but also because the fitting of T 1 experimental data by the theory constitutes an interesting tool for the characterization of the nanoparticles. In this work, T 2 of suspensions of iron oxide particles in different solvents and at different temperatures, corresponding to different proton diffusion properties, were measured and were compared to the three main theoretical models (the motional averaging regime, the static dephasing regime, and the partial refocusing model) with good qualitative agreement. However, a real quantitative agreement was not observed, probably because of the complexity of these nanoparticulate systems. The Roch theory, developed in the motional averaging regime (MAR), was also successfully used to fit T 1 nuclear magnetic relaxation dispersion (NMRD) profiles, even outside the MAR validity range, and provided a good estimate of the particle size. On the other hand, the simultaneous fitting of T 1 and T 2 NMRD profiles by the theory was impossible, and this occurrence constitutes a clear limitation of the Roch model. Finally, the theory was shown to satisfactorily fit the deuterium T 1 NMRD profile of superparamagnetic particle suspensions in heavy water.
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Affiliation(s)
- Y Gossuin
- Biomedical Physics Department, University of Mons, 24, Avenue du Champ de Mars, B-7000, Mons, Belgium
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