Search results for "Intron"
showing 10 items of 420 documents
A functional analysis of ACP-20, an adult-specific cuticular protein gene from the beetle Tenebrio. Role of an intronic sequence in transcriptional a…
2004
0962-1075 (Print) Comparative Study Journal Article Research Support, Non-U.S. Gov't; A gene encoding the adult cuticular protein ACP-20 was isolated in Tenebrio. It consists of three exons interspersed by two introns, intron 1 interrupting the signal peptide. To understand the regulatory mechanisms of ACP-20 expression, ACP-20 promoter-luciferase reporter gene constructs were transfected into cultured pharate adult wing epidermis. Transfection assays needed the presence of 20-hydroxyecdysone, confirming that ACP-20 is up-regulated by ecdysteroids. Analysis of 5' deletion constructs revealed that three regions are necessary for high levels of transcription. Interaction experiments between i…
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…
Femtosecond formation dynamics of the spin Seebeck effect revealed by terahertz spectroscopy
2018
Understanding the transfer of spin angular momentum is essential in modern magnetism research. A model case is the generation of magnons in magnetic insulators by heating an adjacent metal film. Here, we reveal the initial steps of this spin Seebeck effect with <27fs time resolution using terahertz spectroscopy on bilayers of ferrimagnetic yttrium-iron garnet and platinum. Upon exciting the metal with an infrared laser pulse, a spin Seebeck current $j_\textrm{s}$ arises on the same ~100fs time scale on which the metal electrons thermalize. This observation highlights that efficient spin transfer critically relies on carrier multiplication and is driven by conduction electrons scattering …
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.
Investigating spintronics thin film systems with synchrotron radiation
2009
Abstract Spintronics is a research field involving a wide variety of different magnetic materials. Synchrotron radiation in the VUV and soft X-ray regime is ideally suited to investigate the relationships between magnetic properties and electronic structure of spintronics thin film stacks. Complex layered structures and nanomagnets are the main building blocks for current and future spintronics applications. In this contribution we describe the study of spintronics model systems with respect to the static and dynamic behavior with an emphasis on interfaces.
Quaternary Heusler compounds Co(2-x)Rh(x)MnZ (Z = Ga, Sn, Sb): crystal structure, electronic structure, and magnetic properties.
2012
Within the huge family of Heusler compounds only a few quaternary derivatives are known that crystallize in the F43m space group. In this work, the yet unreported compounds CoRhMnZ (Z = Ga, Sn, Sb) and the alloy Co(0.5)Rh(1.5)MnSb were investigated in detail by experimental techniques and theoretical methods. The ab initio calculations predict the CoRhMnZ compounds to be half-metallic ferromagnets or to be close to the half-metallic ferromagnetic state. Calculations of the elastic constants show that the cubic structure is stable in compounds containing Mn. Both calculations and experiment reveal that Mn cannot be exchanged by Fe (CoRhFeGa). The low temperature magnetization of the compound…
Metal-Controlled Magnetoresistance at Room Temperature in Single-Molecule Devices
2017
The appropriate choice of the transition metal complex and metal surface electronic structure opens the possibility to control the spin of the charge carriers through the resulting hybrid molecule/metal spinterface in a single-molecule electrical contact at room temperature. The single-molecule conductance of a Au/molecule/Ni junction can be switched by flipping the magnetization direction of the ferromagnetic electrode. The requirements of the molecule include not just the presence of unpaired electrons: the electronic configuration of the metal center has to provide occupied or empty orbitals that strongly interact with the junction metal electrodes and that are close in energy to their F…
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…
Large negative magnetoresistance effects in Co2Cr0.6Fe0.4Al
2003
Abstract Materials, which display large changes in resistivity in response to an applied magnetic field (magnetoresistance) are currently of great interest due to their potential for applications in magnetic sensors, magnetic random access memories, and spintronics. Guided by striking features in the electronic structure of several magnetic compounds, we prepared the Heusler compound Co2Cr0.6Fe0.4Al. Based on our band structure calculations, we have chosen this composition in order to obtain a half-metallic ferromagnet with a van Hove singularity in the vicinity of the Fermi energy in the majority spin channel and a gap in the minority spin channel. We find a magnetoresistive effect of 30% …
Antiferromagnetic Insulatronics: spintronics without magnetic fields
2021
While known for a long time, antiferromagnetically ordered systems have previously been considered, as expressed by Louis Neel in his Nobel Prize Lecture, to be “interesting but useless”. However, since antiferromagnets potentially promises faster operation, enhanced stability with respect to interfering magnetic fields and higher integration due to the absence of dipolar coupling, they could potentially become a game changer for new spintronic devices. The zero net moment makes manipulation using conventional magnetic fields challenging. However recently, these materials have received renewed attention due to possible manipulation based on new approaches such as photons or spin-orbit torqu…