The elementary excitations of magnets are called spin waves, and their corresponding quasi-particles are known as magnons. The rapidly growing field of Magnonics aims at using them as information... Show moreThe elementary excitations of magnets are called spin waves, and their corresponding quasi-particles are known as magnons. The rapidly growing field of Magnonics aims at using them as information carriers in a new generation of electronic devices, (almost) free of electric currents. Encoding information in the amplitude and/or phase of these coherent waves could lead to a drastic decrease in dissipated power, typically related to the motion of electrons ("Joule" or "Ohmic" heating).This dissertation describes the development and use of a new technique to study spin waves. This technique uses the electronic spins associated with nitrogen-vacancy (NV) centers as magnetic field sensors. An NV center is a light-emitting defect in the crystal lattice of diamond. Remarkably, the brightness of its emission depends on its spin state, sensitive to magnetic fields. This way, magnetic information can be investigated optically. Show less
Triplet superconductivity refers to a condensate of equal-spin Cooper pairs (pairs of electrons with equal spin). While exceptionally rare in nature, triplet pairing of electrons can occur if... Show moreTriplet superconductivity refers to a condensate of equal-spin Cooper pairs (pairs of electrons with equal spin). While exceptionally rare in nature, triplet pairing of electrons can occur if either the temporal or spatial component of the superconducting wavefunction can be represented by an odd function. These are often referred to as odd-frequency and odd-parity triplets, respectively. We use hybrid magnetic devices to study the former, while the latter is investigated in mesoscopic structures of strontium ruthenate (Sr\tss{2}RuO\tss{4}). Show less
In this PhD thesis we investigated the feasibility to build a spin-flip laser, a spintronic device recently proposed by Kadigrobov that can emit radiation within the so-called terahertz gap. In the... Show moreIn this PhD thesis we investigated the feasibility to build a spin-flip laser, a spintronic device recently proposed by Kadigrobov that can emit radiation within the so-called terahertz gap. In the first part of this thesis, we describe point contact spectroscopy experiments which were meant as a first step to the final observation of radiation coming from the spin-flip laser. The ferromagnet used in our spin-flip laser is SmCo5, a hard ferromagnet with a very large coercive field. The next chapter of the thesis describes the sputter growth of thin films of Sm-Co. We found that one of the main problems of building a spin-flip laser is the issue of spin current injection and the relaxation of the spin current in an adjacent layer. In the last chapters of the thesis, we use the ferromagnetic resonance technique to study how the spin currents behave at the interface of a ferromagnet and a normal metal with large spin-orbit coupling, such as Pt or Pd or a normal metal with weak spin-orbit coupling, such as Cu. Show less
The effect of spin-orbit coupling on various quantum transport phenomena is considered. The main topics discussed are: * How spin-orbit coupling can induce shot noise through trajectory splitting. ... Show moreThe effect of spin-orbit coupling on various quantum transport phenomena is considered. The main topics discussed are: * How spin-orbit coupling can induce shot noise through trajectory splitting. * How spin-orbit coupling can degrade electron-hole entanglement (created by a tunnel barrier) by mode mixing. * Mesoscopic Spin Hall effect: longitudinal charge current leads to transverse spin currents in a chaotic electron cavity which has universal fluctuations around a zero mean. * How smooth disorder increases the conductivity of a graphene sheet. In addition a detailed introduction is given to both the origin of spin-orbit coupling and the consequences of time reversal symmetry in quantum systems. Show less
