Anomalous magnetic transport in ferromagnetic graphene junctions

Voltage-induced ferromagnetic resonance in magnetic tunnel junctions.

We demonstrate excitation of ferromagnetic resonance in CoFeB/MgO/CoFeB magnetic tunnel junctions (MTJs) by the combined action of voltage-controlled magnetic anisotropy (VCMA) and spin transfer torque (ST). Our measurements reveal that GHz-frequency VCMA torque and ST in low-resistance MTJs have similar magnitudes, and thus that both torques are equally important for understanding high-frequen...

Transport properties of armchair graphene nanoribbon junctions between graphene electrodes.

The transmission properties of armchair graphene nanoribbon junctions between graphene electrodes are investigated by means of first-principles quantum transport calculations. First the dependence of the transmission function on the size of the nanoribbon has been studied. Two regimes are highlighted: for a small applied bias transport takes place via tunneling and the length of the ribbon is t...

Quantized Transport in Graphene p-n Junctions in a Magnetic Field.

Recent experimental work on locally gated graphene layers resulting in p-n junctions has revealed the quantum Hall effect in their transport behavior. We explain the observed conductance quantization, which is fractional in the bipolar regime and an integer in the unipolar regime, in terms of quantum Hall edge modes propagating along and across the p-n interface. In the bipolar regime, the elec...

Spontaneous Magnetic Flux Induced by Ferromagnetic π-Junctions

Anomalous transport in biased ac-driven Josephson junctions: Negative conductances

We investigate classical anomalous electrical transport in a driven, resistively, and capacitively shunted Josephson junction device. Intriguing transport phenomena are identified in chaotic regimes when the junction is subjected to both a time-periodic ac and a constant biasing dc current. The dependence of the voltage across the junction on the dc exhibits a rich diversity of anomalous transp...