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The mechanism of anomalous resistivity is still an open and unsolved problem in collisionless magnetic reconnection. Studies show that magnetic reconnection regions often have magnetic island-chain structures. By using the test particle simulation, the chaos-induced resistivity is calculated in the regions around X points and O points, respectively. The results show that the chaos-induced resistivity in the X-type region is higher than that in the O-type region by an order of magnitude for the case with a strong guide field or a high magnetic island parameter. For the case of a weak guide field, however, the chaos-induced resistivity in the X-type region sensitively depends on the guide field and may be close to or less than that in the O-type region in the case of a low magnetic island parameter. This work will be helpful for us to understand the magnetic energy dissipation of occurring in collisionless reconnection regions as well as the dynamical evolution of reconnection current sheets. [ABSTRACT FROM AUTHOR]

A strain sensor using a stress-magnetoresistance effect of a Ni-Fe/Mn-Ir exchange-coupled magnetic film was fabricated and evaluated. The stress magnetoresistance is used in the inverse magnetostrictive effect and the magnetoresistance effect in the magnetic film since an external stress is changed into an electric resistance in it. A compressive stress was measured by the strain sensor with a Mn-Ir (10 nm)/Ni-Fe (50 nm)/Ru (1 nm) exchange-coupled film. The change in resistivity ▵p/p is proportional to the applied compressive stress σ for σ⩽50 MPa in the strain sensor. When increasing Ni-Fe layer thickness in the strain sensor, a gauge factor increased. [ABSTRACT FROM AUTHOR]

We present a model to investigate the lateral transport and anisotropic magnetoresistance (AMR) of a permalloy film, with a two-dimensional array of unfilled holes (antidotes). The current density distribution j is first obtained numerically by solving the Poisson equation in the absence of B field, while the magnetization M of the film is calculated via micromagnetics. The M and j distributions are linearly interpolated through the sample, and then combined in a self-consistent scheme to obtain the galvanomagnetic effects (normal and planar Hall effects), which affect the current direction. The overall AMR is evaluated from the parallel contributions of the resulting current paths. Modifying the film geometry by reducing the antidot spacing results in an increase in the peak AMR ratio, which may be explained by the inhomogeneous current density and magnetization alignment induced by the antidots. [ABSTRACT FROM AUTHOR]

Features the magneto-optical properties of ion-implanted iron (Fe) films along with structural changes of Fe films induced by terbium-, bismuth-, and Fe-ion implantations. Polar Kerr rotation in a static magnetic field; Faraday rotation in a pulse magnetic field; Enhancement of the Faraday rotation in the ion implanted Fe layer.

FeSe films have been grown on GaAs (001) substrates by low-pressure metal organic vapor deposition at different temperatures. X-ray diffraction analysis indicated that the FeSe films grown at substrate temperatures (Ts) between 220 and 340 °C were preferentially oriented with tetragonal structure. It was not possible to deposit films at Ts above 400 °C. The atomic molar ratios of Se/Fe increased with increasing the flow rate of H2Se/Fe(CO)5 and the growth temperature. The electronic property results showed that the conductive type of FeSe could be adjusted by controlling the growth temperature. The coercivity of FeSe decreased with increasing the growth temperature from 220 to 300 °C due to the improvement of crystal quality. [ABSTRACT FROM AUTHOR]

FeSe film was prepared on GaAs (001) substrate by low pressure metal-organic chemical vapor deposition. The x-ray diffraction measurement indicated that the sample was preferentially oriented with tetragonal structure. The structure relationship between FeSe epilayer and GaAs (001) substrate has been studied. The critical behavior in the temperature-dependent resistivity at ∼290 K is close to the Curie temperature, which confirmed that the transformation from ferromagnetism to paramagnetism could be responsible for the critical behavior. [ABSTRACT FROM AUTHOR]

The optical and electrical properties of FeSe thin films are studied by both optical absorption and Hall measurements, which suggest that ferromagnetic FeSe is a metal instead of a semiconductor. No absorption gap is observed in the whole spectrum range from far infrared to ultraviolet. Temperature dependent transport measurement indicates that FeSe has a resistivity about 10-3 Ω cm. It is also found that there is a transition from n-type conductivity at low temperatures to p-type conductivity at higher temperatures in FeSe, which is attributed to the two-carrier transport nature and the thermal activation of localized carriers in the thin film. [ABSTRACT FROM AUTHOR]

Capacitive and inductive stochastic heating rely on the repeated interaction of electrons with a localized oscillating electromagnetic structure, such as an electric sheath or a magnetic skin depth. The periodic interaction with a third type of localized structure, the zero line of a linear magnetic field, also provides an efficient means to sustain radio frequency low pressure discharges. In order to calculate the stochastic heating rate, the relevant variables are identified and the electron orbits are classified. Then the kinetic theory of collisionless heating in this type of magnetized discharge is developed. The stochasticity threshold and the quasilinear equation are derived to evaluate the collisionless absorption. The analytical scaling of the heating threshold and the collisionless power absorption are expressed and discussed as a function of the discharge parameters. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]