High-resolution records of the upper Olduvai geomagnetic field reversal were obtained from two localities within steeply dipping lacustrine sediments of the Confidence Hills, southern Death Valley, California . The difference in bedding attitude between the two localities allowed us to perform a fold test of both transitional and non-transitional paleomagnetic directions. This is the first posi...

We calculate the rate of decrease of the expectation value of the transverse component of spin for spin-1/2 particles in a magnetic field with a spatial gradient, to determine the conditions under which a previous classical description is valid. A density matrix treatment is required for two reasons. The first arises because the particles initially are not in a pure state due to thermal motion....

To prevent irreversible demagnetization of a permanent magnet (PM) for interior permanent magnet synchronous motors (IPMSMs) by flux-weakening control, a robust PM flux-linkage nonsingular fast terminal-sliding-mode observer (NFTSMO) is proposed to detect demagnetization faults. First, the IPMSM mathematical model of demagnetization is presented. Second, the construction of the NFTSMO to estima...

We report ab initio simulations of the quantum dynamics of electronic charge and spins when subjected to intense laser pulses. By performing these purely electron-dynamics calculations for a thin film and for the bulk of Ni, we conclude that formation of surfaces has a dramatic influence of amplifying the laser induced demagnetization. The reason for this amplification is enhanced spin-currents...

Some rocks contain multiple remanence “components,” each of which preserves a record different magnetic field. The temperature ranges over these components unblock can overlap, making it difficult to determine their directions. We present data analysis tool called Thermal Resolution Of Unblocking Temperatures (TROUT) that treats the process thermal demagnetization as function (or alternating fi...

Abstract To assess the feasibility of using high-temperature superconductors for beam screens future circular colliders, we have undertaken a study power dependence microwave surface resistance in state-of-the-art REBCO coated conductors at about 8 GHz and 50 K. We employed dielectric resonator to produce radio-frequency (RF) electromagnetic fields on having amplitudes similar those generated b...

The laser-induced ultrafast demagnetization of CoFeB/MgO/CoFeB magnetic tunneling junction is exploited by time-resolved magneto-optical Kerr effect (TRMOKE) for both the parallel state (P state) and the antiparallel state (AP state) of the magnetizations between two magnetic layers. It was observed that the demagnetization time is shorter and the magnitude of demagnetization is larger in the A...

We consider a lowest-order finite element scheme for the Landau-Lifshitz-Gilbert equation (LLG) which describes the dynamics of micromagnetism. In contrast to previous works from the mathematics literature, we examine LLG including the total magnetic field induced by physical phenomena described in terms of exchange energy, anisotropy energy, magnetostatic energy, as well as Zeeman energy. Besi...