Publications by authors named "Mantao Huang"

9 Publications

  • Page 1 of 1

Voltage control of ferrimagnetic order and voltage-assisted writing of ferrimagnetic spin textures.

Nat Nanotechnol 2021 Jul 29. Epub 2021 Jul 29.

Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.

Voltage control of magnetic order is desirable for spintronic device applications, but 180° magnetization switching is not straightforward because electric fields do not break time-reversal symmetry. Ferrimagnets are promising candidates for 180° switching owing to a multi-sublattice configuration with opposing magnetic moments of different magnitudes. In this study we used solid-state hydrogen gating to control the ferrimagnetic order in rare earth-transition metal thin films dynamically. Electric field-induced hydrogen loading/unloading in GdCo can shift the magnetic compensation temperature by more than 100 K, which enables control of the dominant magnetic sublattice. X-ray magnetic circular dichroism measurements and ab initio calculations indicate that the magnetization control originates from the weakening of antiferromagnetic exchange coupling that reduces the magnetization of Gd more than that of Co upon hydrogenation. We observed reversible, gate voltage-induced net magnetization switching and full 180° Néel vector reversal in the absence of external magnetic fields. Furthermore, we generated ferrimagnetic spin textures, such as chiral domain walls and skyrmions, in racetrack devices through hydrogen gating. With gating times as short as 50 μs and endurance of more than 10,000 cycles, our method provides a powerful means to tune ferrimagnetic spin textures and dynamics, with broad applicability in the rapidly emerging field of ferrimagnetic spintronics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41565-021-00940-1DOI Listing
July 2021

Observation of fluctuation-mediated picosecond nucleation of a topological phase.

Nat Mater 2021 Jan 5;20(1):30-37. Epub 2020 Oct 5.

European XFEL, Schenefeld, Germany.

Topological states of matter exhibit fascinating physics combined with an intrinsic stability. A key challenge is the fast creation of topological phases, which requires massive reorientation of charge or spin degrees of freedom. Here we report the picosecond emergence of an extended topological phase that comprises many magnetic skyrmions. The nucleation of this phase, followed in real time via single-shot soft X-ray scattering after infrared laser excitation, is mediated by a transient topological fluctuation state. This state is enabled by the presence of a time-reversal symmetry-breaking perpendicular magnetic field and exists for less than 300 ps. Atomistic simulations indicate that the fluctuation state largely reduces the topological energy barrier and thereby enables the observed rapid and homogeneous nucleation of the skyrmion phase. These observations provide fundamental insights into the nature of topological phase transitions, and suggest a path towards ultrafast topological switching in a wide variety of materials through intermediate fluctuating states.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41563-020-00807-1DOI Listing
January 2021

Fast Magneto-Ionic Switching of Interface Anisotropy Using Yttria-Stabilized Zirconia Gate Oxide.

Nano Lett 2020 May 4;20(5):3435-3441. Epub 2020 May 4.

Center for Spintronics, Korea Institute of Science and Technology, Seoul 02792, Korea.

Voltage control of interfacial magnetism has been greatly highlighted in spintronics research for many years, as it might enable ultralow power technologies. Among a few suggested approaches, magneto-ionic control of magnetism has demonstrated large modulation of magnetic anisotropy. Moreover, the recent demonstration of magneto-ionic devices using hydrogen ions presented relatively fast magnetization toggle switching, ∼ 100 ms, at room temperature. However, the operation speed may need to be significantly improved to be used for modern electronic devices. Here, we demonstrate that the speed of proton-induced magnetization toggle switching largely depends on proton-conducting oxides. We achieve ∼1 ms reliable (>10 cycles) switching using yttria-stabilized zirconia (YSZ), which is ∼100 times faster than the state-of-the-art magneto-ionic devices reported to date at room temperature. Our results suggest that further engineering of the proton-conducting materials could bring substantial improvement that may enable new low-power computing scheme based on magneto-ionics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.nanolett.0c00340DOI Listing
May 2020

Nonlocal Detection of Out-of-Plane Magnetization in a Magnetic Insulator by Thermal Spin Drag.

Phys Rev Lett 2020 Jan;124(2):027701

Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.

We demonstrate a conceptually new mechanism to generate an in-plane spin current with out-of-plane polarization in a nonmagnetic metal, detected by nonlocal thermoelectric voltage measurement. We generate out-of-plane (∇T_{OP}) and in-plane (∇T_{IP}) temperature gradients, simultaneously, acting on a magnetic insulator-Pt bilayer. When the magnetization has a component oriented perpendicular to the plane, ∇T_{OP} drives a spin current into Pt with out-of-plane polarization due to the spin Seebeck effect. ∇T_{IP} then drags the resulting spin-polarized electrons in Pt parallel to the plane against the gradient direction. This finally produces an inverse spin Hall effect voltage in Pt, transverse to ∇T_{IP} and proportional to the out-of-plane component of the magnetization. This simple method enables the detection of the perpendicular magnetization component in a magnetic insulator in a nonlocal geometry.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1103/PhysRevLett.124.027701DOI Listing
January 2020

Voltage-gated optics and plasmonics enabled by solid-state proton pumping.

Nat Commun 2019 11 6;10(1):5030. Epub 2019 Nov 6.

Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.

Devices with locally-addressable and dynamically tunable optical properties underpin emerging technologies such as high-resolution reflective displays and dynamic holography. The optical properties of metals such as Y and Mg can be reversibly switched by hydrogen loading, and hydrogen-switched mirrors and plasmonic devices have been realized, but challenges remain to achieve electrical, localized and reversible control. Here we report a nanoscale solid-state proton switch that allows for electrical control of optical properties through electrochemical hydrogen gating. We demonstrate the generality and versatility of this approach by realizing tunability of a range of device characteristics including transmittance, interference color, and plasmonic resonance. We further discover and exploit a giant modulation of the effective refractive index of the gate dielectric. The simple gate structure permits device thickness down to ~20 nanometers, which can enable device scaling into the deep subwavelength regime, and has potential applications in addressable plasmonic devices and reconfigurable metamaterials.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-019-13131-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6834670PMC
November 2019

M13 Virus-Based Framework for High Fluorescence Enhancement.

Small 2019 07 27;15(28):e1901233. Epub 2019 May 27.

Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.

Fluorescence imaging is a powerful tool for studying biologically relevant macromolecules, but its applicability is often limited by the fluorescent probe, which must demonstrate both high site-specificity and emission efficiency. In this regard, M13 virus, a versatile biological scaffold, has previously been used to both assemble fluorophores on its viral capsid with molecular precision and to also target a variety of cells. Although M13-fluorophore systems are highly selective, these complexes typically suffer from poor molecular detection limits due to low absorption cross-sections and moderate quantum yields. To overcome these challenges, a coassembly of the M13 virus, cyanine 3 dye, and silver nanoparticles is developed to create a fluorescent tag capable of binding with molecular precision with high emissivity. Enhanced emission of cyanine 3 of up to 24-fold is achieved by varying nanoparticle size and particle-fluorophore separation. In addition, it is found that the fluorescence enhancement increases with increasing dye surface density on the viral capsid. Finally, this highly fluorescent probe is applied for in vitro staining of E. coli. These results demonstrate an inexpensive framework for achieving tuned fluorescence enhancements. The methodology developed in this work is potentially amendable to fluorescent detection of a wide range of M13/cell combinations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/smll.201901233DOI Listing
July 2019

Magneto-ionic control of magnetism using a solid-state proton pump.

Nat Mater 2019 01 12;18(1):35-41. Epub 2018 Nov 12.

Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.

Voltage-gated ion transport as a means of manipulating magnetism electrically could enable ultralow-power memory, logic and sensor technologies. Earlier work made use of electric-field-driven O displacement to modulate magnetism in thin films by controlling interfacial or bulk oxidation states. However, elevated temperatures are required and chemical and structural changes lead to irreversibility and device degradation. Here we show reversible and non-destructive toggling of magnetic anisotropy at room temperature using a small gate voltage through H pumping in all-solid-state heterostructures. We achieve 90° magnetization switching by H insertion at a Co/GdO interface, with no degradation in magnetic properties after >2,000 cycles. We then demonstrate reversible anisotropy gating by hydrogen loading in Pd/Co/Pd heterostructures, making metal-metal interfaces susceptible to voltage control. The hydrogen storage metals Pd and Pt are high spin-orbit coupling materials commonly used to generate perpendicular magnetic anisotropy, Dzyaloshinskii-Moriya interaction, and spin-orbit torques in ferromagnet/heavy-metal heterostructures. Thus, our work provides a platform for voltage-controlled spin-orbitronics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41563-018-0211-5DOI Listing
January 2019

Three-terminal resistive switch based on metal/metal oxide redox reactions.

Sci Rep 2017 08 7;7(1):7452. Epub 2017 Aug 7.

Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA.

A solid-state three-terminal resistive switch based on gate-voltage-tunable reversible oxidation of a thin-film metallic channel is demonstrated. The switch is composed of a cobalt wire placed under a GdOx layer and a Au top electrode. The lateral resistance of the wire changes with the transition between cobalt and cobalt oxide controlled by a voltage applied to the top electrode. The kinetics of the oxidation and reduction process are examined through time- and temperature-dependent transport measurements. It is shown that that reversible voltage induced lateral resistance switching with a ratio of 10 can be achieved at room temperature. The reversible non-volatile redox reaction between metal and metal oxide may provide additional degrees of freedom for post-fabrication control of properties of solid-state materials. This type of three-terminal device has potential applications in neuromorphic computing and multilevel data storage, as well as applications that require controlling a relatively large current.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-017-06954-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5547166PMC
August 2017

Crystallographic data of double antisymmetry space groups.

Acta Crystallogr A Found Adv 2014 Jul 18;70(Pt 4):373-81. Epub 2014 Jun 18.

Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16801, USA.

This paper presents crystallographic data of double antisymmetry space groups, including symmetry-element diagrams, general-position diagrams and positions, with multiplicities, site symmetries, coordinates, spin vectors, roto vectors and displacement vectors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1107/S2053273314006871DOI Listing
July 2014
-->