Controlling Magnetism with Light in a Zero Orbital Angular Momentum Antiferromagnet

Antiferromagnetic materials feature intrinsic ultrafast spin dynamics, making them ideal candidates for future magnonic devices operating at THz frequencies. A major focus of current research is the investigation of optical methods for the efficient generation of coherent magnons in antiferromagnetic insulators. In magnetic lattices endowed...

Ultrafast activation of the double-exchange interaction in antiferromagnetic manganites

In doped manganite systems, strong electronic correlations result in rich phase diagrams where electron delocalization strongly affects the magnetic order. Here, we employ a femtosecond all-optical pump-probe scheme to impulsively photodope the antiferromagnetic parent manganite system CaMnO₃ and unveil the formation dynamics of a...

Resonant optical control of magnetism on ultrashort timescales

Excitation of optical transitions in solids using ultrashort pulses of light allows to selectively perturb microscopic degrees of freedom in order to change and control material properties on very short timescales. In this thesis we study how ultrafast resonant excitation of optical transitions can induce coherent structural dynamics in wide...

Systematic solvent screening and selection for polyhydroxyalkanoates (PHBV) recovery from biomass

The biotechnological production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) derived from organic waste streams by mixed microbial communities is well established at the pilot-level. However, there is limited research on the recovery of the biopolymer from the microbial biomass, while its impact on product quality and product costs...

Coupling Charge and Topological Reconstructions at Polar Oxide Interfaces

In oxide heterostructures, different materials are integrated into a single artificial crystal, resulting in a breaking of inversion symmetry across the heterointerfaces. A notable example is the interface between polar and nonpolar materials, where valence discontinuities lead to otherwise inaccessible charge and spin states. This approach...

Controlling the anisotropy of a van der Waals antiferromagnet with light

Van der Waals magnets provide an ideal playground to explore the fundamentals of low-dimensional magnetism and open opportunities for ultrathin spin-processing devices. The Mermin-Wagner theorem dictates that as in reduced dimensions isotropic spin interactions cannot retain long-range correlations, the long-range spin order is stabilized by...

Ultrafast control of magnetic interactions via light-driven phonons

Resonant ultrafast excitation of infrared-active phonons is a powerful technique with which to control the electronic properties of materials that leads to remarkable phenomena such as the light-induced enhancement of superconductivity^1,2, switching of ferroelectric polarization^3,4 and ultrafast insulator-to-metal...

Ultrafast strain engineering and coherent structural dynamics from resonantly driven optical phonons in LaAlO₃

Strain engineering has been extended recently to the picosecond timescales, driving ultrafast metal–insulator phase transitions and the propagation of ultrasonic demagnetization fronts. However, the nonlinear lattice dynamics underpinning interfacial optoelectronic phase switching have not yet been addressed. Here we perform time-resolved all...

Berry phase engineering at oxide interfaces

Three-dimensional strontium ruthenate (SrRuO3) is an itinerant ferromagnet that features Weyl points acting as sources of emergent magnetic fields, anomalous Hall conductivity, and unconventional spin dynamics. Integrating SrRuO3 in oxide heterostructures is potentially a novel route to engineer emergent electrodynamics, but its electronic...

Temperature dependent inverse spin Hall effect in Co/Pt spintronic emitters

In bilayers of ferromagnets and heavy metals, which form the so-called spintronic emitters, the phenomena of ultrafast demagnetization and the inverse spin Hall effect (ISHE) conspire to yield remarkably efficient emission of electric pulses in the THz band. Light-induced demagnetization of the ferromagnet launches a pulse of spin current...

Electrodynamic response of mesoscopic objects: Carbon nanotubes and superconducting nanowires

Microwave-induced nonequilibrium temperature in a suspended carbon nanotube

Antenna-coupled suspended single carbon nanotubes exposed to 108?GHz microwave radiation are shown to be selectively heated with respect to their metal contacts. This leads to an increase in the conductance as well as to the development of a power-dependent DC voltage. The increased conductance stems from the temperature dependence of tunneling...

Critical-current reduction in thin superconducting wires due to current crowding

We demonstrate experimentally that the critical current in superconducting NbTiN wires is dependent on their geometrical shape, due to current-crowding effects. Geometric patterns such as 90? corners and sudden expansions of wire width are shown to result in the reduction of critical currents. The results are relevant for single-photon detectors...

Noise in NbTiN, Al, and Ta Superconducting Resonators on Silicon and Sapphire Substrates

We present measurements of the frequency noise and resonance frequency temperature dependence in planar superconducting resonators on both silicon and sapphire substrates. We show, by covering the resonators with sputtered SiOx layers of different thicknesses, that the temperature dependence of the resonance frequency scales linearly with...

Contribution of dielectrics to frequency and noise of NbTiN superconducting resonators

We study NbTiN resonators by measurements of the temperature dependent resonance frequency and frequency noise. Additionally, resonators are studied covered with SiOx dielectric layers of various thicknesses. The resonance frequency develops a nonmonotonic temperature dependence with increasing SiOx layer thickness. The increase in the noise is...