An experimental demonstration of electrical detection of coherent spin motion of weakly coupled, localized electron spins in thin fullerene C60 films at room temperature is presented. Pulsed electrically detected magnetic resonance experiments on vertical photocurrents through Al/C(60)/ZnO samples showed that an electron spin Rabi oscillation is reflected by transient current changes. The nature of possible microscopic mechanisms responsible for this spin to charge conversion as well as its implications for the readout of endohedral fullerene (N@C(60)) spin qubits are discussed.

Articles you may be interested inEnhanced performance of solar cells with optimized surface recombination and efficient photon capturing via anisotropic-etching of black silicon Appl. Phys. Lett.Effect of plasma polymerization film on reducing damage of reactive ion etched silicon substrates with CHF3+O2 plasmas J.New concepts in silicon solar cell design require dry processing technologies. For this reason two reactive ion etching ͑RIE͒ processes have been developed: one for surface cleaning and one for the removal of phosphorous glass ͑PSG͒. However, damage is induced in silicon during reactive ion etching which deteriorates solar cell performance. Damage caused by SF 6 RIE cleaning has been investigated by means of secondary ion mass spectroscopy, positron annihilation, and minority charge carrier lifetime measurements. Particles contained in the etch gas can be detected up to a depth of 50-80 nm in the silicon sample. A two layer model of vacancy distribution has been established: A layer of high vacancy concentration (10 19 cm Ϫ3 ) up to a depth of 20 nm is followed by a second layer that extends over a depth of 1 m with a vacancy concentration of 10 16 cm Ϫ3 . Effective minority charge carrier lifetimes decrease to about 10% of the lifetime of the wet etched control during RIE. If a heavily damaged layer of 20 nm is being removed by anodic oxidation, lifetimes return to the initial value. Under certain etching conditions it is possible to anneal plasma induced damage at 400°C. The influence of RIE induced damage on solar cells is quantified by open circuit voltage analysis: Long process times, addition of oxygen to the etch gas, and high rf power or self-induced dc bias result in a significant decrease in open circuit voltage. Nearly damage free RIE processes have been developed for surface cleaning as well as PSG removal. Dry processed solar cells thus show the same performance as wet etched cells.

We present a new mechanism for spin-wave excitation using a pinned domain wall which is forced to oscillate at its eigenfrequency and radiates spin waves. The domain wall acts as a frequency doubler, as the excited spin waves have twice the frequency of the domain wall oscillation. The investigations have been carried out using micromagnetic simulations and enable the determination of the main characteristics of the excited spin-waves such as frequency, wavelength, and velocity. This behavior is understood by the oscillation in the perpendicular magnetization which shows two anti-nodes oscillating out of phase with respect to each other. PACS numbers:The dynamic properties of ferromagnetic thin films have attracted much attention recently. In particular, the possibility to create logic circuits harvesting magnetic features such as domain walls [1] and spin waves [2,3,4,5] is in the focus of research activities. Thus, the excitation and propagation of spin waves and their interaction with domain walls is relevant to this research interest.In this letter a new mechanism for the excitation and manipulation of spin waves is presented. In case when a pinned domain wall is excited by an external field with its eigenfrequency, a "steady-state" oscillation forms with this eigenfrequency and a distinct amplitude which is determined by the balance between energy dissipation processes due to damping and the external triggering by the applied field. The energy pumped into the system by the external field leads not only to the compensation of the damped oscillation, but also to the radiation of spin waves. It will be shown that the domain wall itself oscillates with the frequency of the externally applied field whereas the spin waves of twice that frequency are allowed to propagate.To demonstrate the principle of a spin-wave frequency doubler, micromagnetic simulations using the LLG-code [6] were performed. The used material is Ni 81 Fe 19 and standard values for this material (saturation magnetization M s =800 G, exchange constant A ex =1.05 µerg/cm 3 ) were used. The sample geometry is presented in Fig.

We investigated the organic device ITO/ZnPc/Al with continuous wave and pulsed electrically detected magnetic resonance (cw‐EDMR/p‐EDMR). Resonant microwave absorption of the sample leads to current changes that can be explained by the theory of spin dependent recombination of localized spin carriers. The coherent spin motion during the microwave pulse shows two frequency components, which can be attributed to spin pairs with large and small Larmor separation. This is supported by the analysis of the cw‐EDMR spectrum, when taking into account exchange coupling between the spin pair partners. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)