Search results for "Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik"
showing 10 items of 223 documents
Introducing coherent time control to cavity magnon-polariton modes
2020
By connecting light to magnetism, cavity-magnon-polaritons (CMPs) can build links from quantum computation to spintronics. As a consequence, CMP-based information processing devices have thrived over the last five years, but almost exclusively been investigated with single-tone spectroscopy. However, universal computing applications will require a dynamic control of the CMP on demand and within nanoseconds. In this work, we perform fast manipulations of the different CMP modes with independent but coherent pulses to the cavity and magnon system. We change the state of the CMP from the energy exchanging beat mode to its normal modes and further demonstrate two fundamental examples of coheren…
Magnetic states in low-pinning high-anisotropy material nanostructures suitable for dynamic imaging
2013
We present magnetic domain states in a material configuration with high (perpendicular) magnetic anisotropy and particularly low magnetic pinning. This material, a B-doped Co/Pt multilayer configuration, exhibits a strong magnetic contrast in x-ray transmission experiments, making it apt for dynamic imaging with modern synchrotron techniques, providing high spatial and high temporal resolution simultaneously. By analyzing the static spin structures in nanodisks at variable external fields, we show that CoB/Pt multilayers exhibit low enough domain wall pinning to manipulate the domain pattern with weak stimuli and in particular to move domains and domain walls. We demonstrate in a proof-of-p…
Magnetic state control via field-angle-selective switching in asymmetric rings
2020
Switching the chirality of the vortex state in asymmetric ferromagnetic rings is interesting for multistate memory devices, logic elements, and stray-field-based rotation sensors. This study shows that different magnetic states can be configured by carefully tuning the magnetic field angle. Using time-resolved scanning electron microscopy with polarization analysis to image the magnetization dynamics of these rings, the authors detect competing switching pathways for certain field angles. These different pathways do not change the resulting magnetic states, though, which is advantageous for engineering reliable devices for a range of potential spintronic applications.
Theory of domain-wall magnetoresistance in metallic antiferromagnets
2020
We develop a theory to compute the domain-wall magnetoresistance (DWMR) in antiferromagnetic (AFM) metals with different spin structures. In the diffusive transport regime, the DWMR can be either {\it negative} or positive depending on the domain-wall orientation and spin structure. In contrast, when the transport is in the ballistic regime, the DWMR is always positive, and the magnitude depends on the width and orientation of the domain wall. Our results pave the way of using electrical measurements for probing the internal spin structure in antiferromagnetic metals.
Magnetoresistance effects in the metallic antiferromagnet Mn$_2$Au
2019
In antiferromagnetic spintronics, it is essential to separate the resistance modifications of purely magnetic origin from other effects generated by current pulses intended to switch the N\'eel vector. We investigate the magnetoresistance effects resulting from magnetic field induced reorientations of the staggered magnetization of epitaxial antiferromagnetic Mn2Au(001) thin films. The samples were exposed to 60 T magnetic field pulses along different crystallographic in-plane directions of Mn2Au(001), while their resistance was measured. For the staggered magnetization aligned via a spin-flop transition parallel to the easy [110]-direction, an ansiotropic magnetoresistance of -0.15 % was m…
Giant Spin Seebeck Effect through an Interface Organic Semiconductor
2019
Interfacing an organic semiconductor C60 with a non-magnetic metallic thin film (Cu or Pt) has created a novel heterostructure that is ferromagnetic at ambient temperature, while its interface with a magnetic metal (Fe or Co) can tune the anisotropic magnetic surface property of the material. Here, we demonstrate that sandwiching C60 in between a magnetic insulator (Y3Fe5O12: YIG) and a non-magnetic, strong spin-orbit metal (Pt) promotes highly efficient spin current transport via the thermally driven spin Seebeck effect (SSE). Experiments and first principles calculations consistently show that the presence of C60 reduces significantly the conductivity mismatch between YIG and Pt and the s…
Harnessing Orbital-to-Spin Conversion of Interfacial Orbital Currents for Efficient Spin-Orbit Torques.
2020
The system generates two errors of "Bad character(s) in field Abstract" for no reason. Please refer to the manuscript for the full abstract.
Microstructure Design for Fast Lifetime Measurements of Magnetic Tunneling Junctions
2019
The estimation of the reliability of magnetic field sensors against failure is a critical point concerning their application for industrial purposes. Due to the physical stochastic nature of the failure events, this can only be done by means of a statistical approach which is extremely time consuming and prevents a continuous observation of the production. Here, we present a novel microstructure design for a parallel measurement of the lifetime characteristics of a sensor population. By making use of two alternative designs and the Weibull statistical distribution function, we are able to measure the lifetime characteristics of a CoFeB/MgO/CoFeB tunneling junction population. The main param…
Modulating the polarization of broadband terahertz pulses from a spintronic emitter at rates up to 10 kHz
2021
Reliable modulation of terahertz electromagnetic waveforms is important for many applications. Here, we rapidly modulate the direction of the electric field of linearly polarized terahertz electromagnetic pulses with 1–30 THz bandwidth by applying time-dependent magnetic fields to a spintronic terahertz emitter. Polarity modulation of the terahertz field with more than 99% contrast at a rate of 10 kHz is achieved using a harmonic magnetic field. By adding a static magnetic field, we modulate the direction of the terahertz field between angles of, for instance, −53° and 53° at kilohertz rates. We believe our approach makes spintronic terahertz emitters a promising source for low-noise modula…
Interfacial Dzyaloshinskii-Moriya interaction and chiral magnetic textures in a ferrimagnetic insulator
2019
The interfacial Dzyaloshinskii-Moriya interaction (DMI) in multilayers of heavy metal and ferromagnetic metals enables the stabilization of novel chiral spin structures such as skyrmions. Magnetic insulators, on the other hand can exhibit enhanced dynamics and properties such as lower magnetic damping and therefore it is of interest to combine the properties enabled by interfacial DMI with insulating systems. Here, we demonstrate the presence of interfacial DMI in heterostructures that include insulating magnetic layers. We use a bilayer of perpendicularly magnetized insulating thulium iron garnet (TmIG) and the heavy metal platinum, and find a surprisingly strong interfacial DMI that, comb…