Magnetic properties and materials

  • Article
    | Open Access

    The Kondo effect has been observed in a variety of systems, including carbon nanotube quantum dots and graphene in the presence of impurities. Here, the authors report the observation of the Kondo effect in bilayer graphene quantum dots and study its interplay with weak spin-orbit coupling.

    • Annika Kurzmann
    • , Yaakov Kleeorin
    •  & Klaus Ensslin
  • Article
    | Open Access

    The band topology of nonmagnetic crystals can be characterized by Topological Quantum Chemistry (TQC), whereas the band topology of magnetic crystals remains unexplored. Here, the authors extend TQC to the magnetic space groups to form a complete, real-space theory of band topology in magnetic and nonmagnetic crystalline solids.

    • Luis Elcoro
    • , Benjamin J. Wieder
    •  & B. Andrei Bernevig
  • Article
    | Open Access

    Quantum spin liquid states are realized in systems with frustrated magnetic interactions. Here, the authors show that tunable frustrated spin-spin interactions can be induced by coupling a quantum antiferromagnet to the quantized light of a driven optical cavity, giving rise to robust quantum spin liquid states.

    • Alessio Chiocchetta
    • , Dominik Kiese
    •  & Sebastian Diehl
  • Article
    | Open Access

    Sr3Ru2O7 exhibits a quantum critical point tunable by magnetic field and has been widely used in the study of criticality. Here, by using inelastic neutron scattering, the authors measure collective magnetic excitations near the quantum critical point and relate them to thermodynamic properties and spin density wave order.

    • C. Lester
    • , S. Ramos
    •  & S. M. Hayden
  • Article
    | Open Access

    Strontium Ruthenate, Sr2RuO4, displays a remarkable number of intriguing physical phenomena, from superconductivity, to strain-induced ferromagnetism. Here, using low-energy muon spectroscopy, Fittipaldi et al. demonstrate the existence of unconventional magnetism at the surface of Sr2RuO4 in its normal state and without any applied strain.

    • R. Fittipaldi
    • , R. Hartmann
    •  & A. Di Bernardo
  • Article
    | Open Access

    Merons and Skyrmions, two topological spin-textures, have attracted a lot of interests due to their potential use in information storage. Here, the authors demonstrate the transformation of Meron pairs into Skyrmions without an applied magnetic field within domain walls of GdFeCo films.

    • Zhuolin Li
    • , Jian Su
    •  & Baogen Shen
  • Article
    | Open Access

    The X-ray magnetic circular dichroism detection of magnetic octupole moment has not been experimentally demonstrated so far. Here, the authors observe ferroic order of magnetic octupole in Mn3Sn, finding the exotic material functionalities related to the multipole order.

    • Motoi Kimata
    • , Norimasa Sasabe
    •  & Tetsuya Nakamura
  • Article
    | Open Access

    The honeycomb lattice with a spin-orbit interaction can give rise to exotic quantum states. With the measurements of bulk properties and inelastic neutron scattering, Lin et al demonstrate the existence of a field induced spin-disordered state in Na2Co2TeO6 and extend the Kitaev model to 3d system.

    • Gaoting Lin
    • , Jaehong Jeong
    •  & Jie Ma
  • Article
    | Open Access

    Resistive switching usually occurs by the formation of conducting filaments in the direction of current flow. Here the authors study an intriguing type of volatile metal-to-insulator resistive switching in (La,Sr)MnO3, which occurs by the formation of an insulating barrier perpendicular to the current.

    • Pavel Salev
    • , Lorenzo Fratino
    •  & Ivan K. Schuller
  • Article
    | Open Access

    Toroidal moments arise from vortex like spin arrangements. These moments can then interact, giving rise to ferri- or ferro-toroidal order, though controlling such order is difficult. Here, the authors demonstrate a ferri-toroidal state in BaCoSiO4, which under an applied magnetic field exhibits multiple toroidal and metamagnetic transitions.

    • Lei Ding
    • , Xianghan Xu
    •  & Huibo Cao
  • Article
    | Open Access

    Anisotropic spin S >1/2 quantum magnets can have multiple low energy modes. In this manuscript, the authors study the interaction of such low energy modes in the S = 1 antiferromagnet Ba2FeSi2O7 by combining neutron scattering measurements with an SU(3) generalization of the 1/S expansion.

    • Seung-Hwan Do
    • , Hao Zhang
    •  & Andrew D. Christianson
  • Article
    | Open Access

    Skyrmions are topological two-dimensional spin textures that in three-dimensional systems resemble strings or tubes. Here, using transmission electron microscopy Zheng et al observe the braiding of skyrmion strings in FeGe and predict this phenomenon for a large family of magnets.

    • Fengshan Zheng
    • , Filipp N. Rybakov
    •  & Rafal E. Dunin-Borkowski
  • Article
    | Open Access

    Triplons are elementary spin excitations characteristic of dimerized magnets, carrying a spin angular momentum one. Here, the authors report evidence for spin current of triplons via thermal transport measurements in a spin-dimer compound CuGeO3.

    • Yao Chen
    • , Masahiro Sato
    •  & Eiji Saitoh
  • Article
    | Open Access

    Skyrmions are a type of topological spin texture that great potential across a wide variety of technological applications. Here, Yu et al. study the thermally driven motion of Skyrmions and find a minimum temperature gradient for the motion of skyrmions two orders of magnitude smaller than for domain walls.

    • Xiuzhen Yu
    • , Fumitaka Kagawa
    •  & Yoshinori Tokura
  • Article
    | Open Access

    Previous work has shown the existence of spin-orbit-entangled excitons and their coupling to antiferromagnetism in the correlated insulator NiPS3. Here the authors show that non-equilibrium driving of these excitons produces a transient metallic antiferromagnetic state that cannot be achieved by tuning the temperature in equilibrium.

    • Carina A. Belvin
    • , Edoardo Baldini
    •  & Nuh Gedik
  • Article
    | Open Access

    Bound states in superconducting vortices are expected to exhibit an electron-hole asymmetry, but it is usually tiny and can be easily washed out. Here, the authors show that the vortex bound states coupling to magnetic impurities provides an axial electron-hole asymmetry on a much longer scale, and that the direction of the asymmetry depends on the band character of the superconducting material.

    • Sunghun Park
    • , Víctor Barrena
    •  & Hermann Suderow
  • Article
    | Open Access

    Ferromagnetic systems rarely display a large or non-saturating magnetoresistance, due to the low Fermi velocity of the predominant charge carrier. Here, the authors show that MnBi, a ferromagnet, bucks this trend, showing both large and non-saturating magnetoresistance, and high charge carrier motilities.

    • Yangkun He
    • , Jacob Gayles
    •  & Claudia Felser
  • Article
    | Open Access

    Understanding the strange metal behavior, characterized by linear-in-temperature resistivity, could shed light on the mechanism of unconventional superconductivity. Here, by using electrical resistivity measurements into the micro-Kelvin regime, the authors report evidence of unconventional superconductivity in the strange metal YbRh2Si2 and propose a possible pairing mechanism.

    • D. H. Nguyen
    • , A. Sidorenko
    •  & S. Paschen
  • Article
    | Open Access

    Thermoelectric effects are limited to electrons to occur, and disappear at low temperatures due to electronic entropy quenching. Here, the authors report thermoelectric generation caused by nuclear spins down to 100 mK due to nuclear-spin excitation in a magnetically ordered material MnCO3.

    • T. Kikkawa
    • , D. Reitz
    •  & E. Saitoh
  • Article
    | Open Access

    In real materials, a spin quantum number assumes a fixed value, which makes it challenging to realize a crossover between quantum and classical spin regimes. Here the authors demonstrate such a crossover in a weakly coupled chain compound by controlling the amount of quantum correlations, in the form of the inverse spin quantum number, with external pressure.

    • Daisuke Yamamoto
    • , Takahiro Sakurai
    •  & Yoshiya Uwatoko
  • Article
    | Open Access

    In this manuscript, the authors grow very thin layers of FeAs in a matrix of InAs. The resulting superlattice displays ferromagnetism, with the Curie temperature varying depending on the layer thickness. These results further illustrate the wide array of intriguing ground states of materials with tetrahedral FeAs bonds

    • Le Duc Anh
    • , Taiki Hayakawa
    •  & Masaaki Tanaka
  • Article
    | Open Access

    Single atom magnets on surfaces offer potentially long lived and stable spin states, particular lanthanides, which can be adsorbed onto Magnesium Oxide. Here, the authors report on Dysprosium adsorbed onto Magnesium Oxide, which exhibits large magnetic anisotropy energy, and a spin life time of several days at low temperatures

    • A. Singha
    • , P. Willke
    •  & T. Choi
  • Article
    | Open Access

    Nuclear spin polarization and relaxation can be studied using nuclear magnetic resonance (NMR). Here the authors demonstrate a combination of fast-field cycling and optical magnetometry techniques, to realize a NMR sensor that operates in the region of very low frequency and high relaxation rate.

    • Sven Bodenstedt
    • , Morgan W. Mitchell
    •  & Michael C. D. Tayler
  • Article
    | Open Access

    The nature of spin interactions and the field-induced quantum spin liquid phase in the Kitaev material α-RuCl3 have been debated. Here, using a combination of many-body techniques, the authors derive an effective spin model that explains the majority of experimental findings and predicts a new quantum spin liquid phase in strong out-of-plane magnetic field.

    • Han Li
    • , Hao-Kai Zhang
    •  & Wei Li
  • Article
    | Open Access

    Recent advances in the identification and growth of antiferromagnetic topological insulators open the way to the manipulation of the chiral edge states that are topologically required at their step edges and domain walls. Here, the authors propose a quantum point junction formed by two types of edge states and discuss its applications in electron quantum optics.

    • Nicodemos Varnava
    • , Justin H. Wilson
    •  & David Vanderbilt
  • Article
    | Open Access

    Van der Waals magnetic materials (vdWs) have allowed for the exploration of the two dimensional limit of magnetism, however, most vdWs are only magnetic at low temperature. Herein, the authors overcome this limitation, observing room temperature magnetic ordering in Cobalt doped graphene-like Zinc-Oxide.

    • Rui Chen
    • , Fuchuan Luo
    •  & Jie Yao
  • Article
    | Open Access

    It was suggested that some 3d materials display bond-dependent exchange interactions, leading to exotic many-body effects. Here, using inelastic neutron scattering, the authors reveal such interactions in the stacked honeycomb magnet CoTiO3 and show how they induce a spectral gap and affect the Dirac magnon band structure.

    • M. Elliot
    • , P. A. McClarty
    •  & R. Coldea
  • Article
    | Open Access

    A field-induced incommensurate spin density wave order was observed in the spin-chain material YbAlO3; however, its mechanism is not fully understood. Here, using neutron scattering and numerical calculations, the authors propose a mechanism based on multiple fermion scattering caused by weak inter-chain coupling.

    • S. E. Nikitin
    • , S. Nishimoto
    •  & A. Podlesnyak
  • Article
    | Open Access

    Experimentally detectable signature of an axion insulator remains elusive. Here, the authors predict a topological phase diagram of MnBi2Te4/(Bi2Te3)n heterostructure, where the chiral hinge mode induced by the surface anomalous Hall conductivity is identified as a signature of an axion insulator state.

    • Mingqiang Gu
    • , Jiayu Li
    •  & Qihang Liu
  • Article
    | Open Access

    It was recently proposed that the coupling between phonons and fractional excitations of a Kitaev quantum spin liquid can be detected in its phonon dynamics. Here, the authors report signatures of this coupling, manifested in low-energy phonon anomalies measured by inelastic X-ray scattering with meV resolution.

    • Haoxiang Li
    • , T. T. Zhang
    •  & H. Miao
  • Article
    | Open Access

    Antiferromagnets (AFM) exhibit faster magnetization dynamics, and have immunity to stray fields, making AFMs attractive for spintronic devices. Here, the authors investigate the behaviour of domain walls in AFMs, and find a new type domain wall, a superposition of two adjacent rotational domains.

    • Jonas Spethmann
    • , Martin Grünebohm
    •  & André Kubetzka
  • Article
    | Open Access

    Domain wall skyrmions have been proposed but the experimental observation has been difficult. Here, the authors report experimental discovery of domain wall bimerons due to the interplay between magnetic anisotropy and Dzyaloshinskii-Moriya interaction in chiral magnet Co-ZnMn(110) thin films.

    • Tomoki Nagase
    • , Yeong-Gi So
    •  & Masahiro Nagao
  • Article
    | Open Access

    Two-dimensional artificial spin-ice systems have been studied for over 15 years but do not capture the detailed geometry of their bulk counterparts. Here, the authors fabricate a three-dimensional artificial spin-ice and show that the surface termination plays a crucial role in dictating the magnetic charge transport.

    • A. May
    • , M. Saccone
    •  & S. Ladak
  • Article
    | Open Access

    Ultrastrong light-matter interactions with dominant antiresonant terms are expected to give rise to interesting phenomena such as quantum fluctuation suppression. Here, the authors propose a system of ultrastrongly coupled magnon modes in a rare earth orthoferrite as a platform for exploring such phenomena.

    • Takuma Makihara
    • , Kenji Hayashida
    •  & Junichiro Kono
  • Article
    | Open Access

    The typical characters of the electronic structure of magnetic kagome materials remain elusive. Here, the authors observe a Dirac cone, a flat band and a saddle point near the Fermi energy in ferromagnetic kagome material YMn6Sn6.

    • Man Li
    • , Qi Wang
    •  & Shancai Wang
  • Article
    | Open Access

    Spinon excitations of a Kagome quantum spin liquid are expected to give rise to a magnetic continuum in Raman spectroscopy. Here, the authors report a magnetic Raman continuum in the Kagome spin liquid candidate Cu3Zn(OH)6FBr, in contrast to a sharp magnon Raman peak in the Kagome antiferromagnet EuCu3(OH)6Cl3.

    • Ying Fu
    • , Miao-Ling Lin
    •  & Jia-Wei Mei
  • Article
    | Open Access

    Spin-ices can exhibit a variety of remarkable phenomena, not least the appearance of emergent magnetic monopoles. In this theory paper, Daniel Khomskii shows that in the moment fragmentation state, the electric dipoles associated with magnetic monopoles become ordered, leading to a change in electrical activity.

    • D. I. Khomskii
  • Article
    | Open Access

    Some one-dimensional chains host fractional excitations at their ends, akin to the hallmark excitations of quantum spin liquids. Here, Savary proposes a realistic model which uses such one-dimensional chains as building blocks for higher-dimensional exotic fluctuating quantum phases.

    • Lucile Savary
  • Article
    | Open Access

    Metallic van der Waals magnets have considerable technological promise, due to their ability to be strongly coupled with electronic currents and integrated in two dimensional heterostructures. Here, Seo et al. demonstrate highly tunable itinerant antiferromagnetism in a van der Waals magnet.

    • Junho Seo
    • , Eun Su An
    •  & Jun Sung Kim
  • Article
    | Open Access

    Quantum degrees of freedom, such as spin or valleys, lie at the basis of many intriguing phenomena. In this theory work, the authors present a new type of spin-valley locking enabled by a crystalline symmetry, which allows for the generation of valley polarizations and net magnetization via strain, and non-collinear spin currents via charge currents.

    • Hai-Yang Ma
    • , Mengli Hu
    •  & Junwei Liu
  • Article
    | Open Access

    Predicting and controlling the (in)stability of thin shells are important tasks in many practical applications but hampered by the presence of imperfections. Here Yan et al. show that when the material composition is magnetic the conditions for collapse can simply be readjusted with external fields.

    • Dong Yan
    • , Matteo Pezzulla
    •  & Pedro M. Reis
  • Article
    | Open Access

    The Mott transition is a celebrated example of a metal-insulator transition driven by electron correlations. Here, using magnetoresistance measurements, the authors demonstrate the presence of a spin-driven metal-insulator transition, where the insulating gap only opens below the Neel temperature.

    • Yejun Feng
    • , Yishu Wang
    •  & T. F. Rosenbaum
  • Article
    | Open Access

    Domains and domain walls can have distinctively different physical properties. Here, the authors show how to transfer domains into domain walls and vice versa while maintaining their physical properties. Thereby the authors tune a multiferroic state between three and two dimensions.

    • E. Hassanpour
    • , M. C. Weber
    •  & M. Fiebig
  • Article
    | Open Access

    In this work, Meisenheimer et al. use careful epitaxial growth of FeGa thin films to achieve a metastable state with remarkably high magetostrictive coefficients. Materials with strong magnetostrictive properties are vital components in magnetoelectric multiferroic heterostructures, with considerable potential for use a variety of technologies.

    • P. B. Meisenheimer
    • , R. A. Steinhardt
    •  & J. T. Heron
  • Article
    | Open Access

    Chiral superconductors are predicted to realize Majorana normal fluid at its boundary, but remain elusive experimentally. Here, Bae et al. report anomalous surface normal fluid response in UTe2 single crystal which is further attributed to a chiral spin-triplet pairing state.

    • Seokjin Bae
    • , Hyunsoo Kim
    •  & Steven M. Anlage