Electrical Resistance Anomaly and Hall Effect in (Fe<SUB>1&minus;<I>x</I></SUB>V<I><SUB>x</SUB></I>)<SUB>3</SUB>Al Alloys

The quantum Hall effect as an electrical resistance standard

The quantum Hall effect (QHE) provides an invariant reference for resistance linked to natural constants. It is used worldwide to maintain and compare the unit of resistance. The reproducibility reached today is almost two orders of magnitude better than the uncertainty of the determination of the ohm in the international system of units SI. In this article, mainly the aspects of the QHE releva...

Unusual Hall effect anomaly in MnSi under pressure.

We report the observation of a highly unusual Hall current in the helical magnet MnSi in an applied pressure P=6-12 kbars. The Hall conductivity displays a distinctive stepwise field profile quite unlike any other Hall response observed in solids. We identify the origin of this Hall current with the effective real-space magnetic field due to chiral spin textures, which may be a precursor of the...

Equivalent Electrical Circuit Representations of AC Quantized Hall Resistance Standards

University of Maryland, College Park, MD 20742-4111 We use equivalent electrical circuits to analyze the effects of large parasitic impedances existing in all sample probes on four-terminal-pair measurements of the ac quantized Hall resistance RH. The circuit components include the externally measurable parasitic capacitances, inductances, lead resistances, and leakage resistances of ac quantiz...

Frequency Dependent Electrical Transport in the Integer Quantum Hall Effect

Quantum Hall Effect as a Resistance Standard

In a two-dimensional electron gas system, the Hall resistance at low temperatures and in strong magnetic field has plateaus as a function of the number of electrons that can be linked to natural constants as RH = h/ie. Due to the high precision of the measurement, the quantization of the Hall resistance is now used as the primary standard of resistance. The paper describes the use of quantum Ha...