We study effect of noise on the tunneling process of the magnetization in a sweeping field from the viewpoint of the nonadiabatic transition. The tunneling probability depends on the properties of the noise, e.g. the direction, the amplitude, and the relaxation time of the autocorrelation function. We investigate the tunneling process in the presence of noise by solving the time-dependent Schrö...

Spatially resolved tunneling spectroscopic studies of colossal magnetoresistive (CMR) manganite La0.7Ca0.3MnO3 (LCMO) epitaxial films on (LaAlO3)0.3(Sr2AlTaO6)0.7 substrate are investigated as functions of temperature, magnetic field and spin polarization by means of scanning tunneling spectroscopy. Systematic surveys of the tunneling spectra taken with Pt/Ir tips reveal spatial variations on t...

scanning hall probe microscopy (shpm) is a scanning probe microscopy technique developed to observe and image magnetic fields locally. this method is based on application of the hall effect, supplied by a micro hall probe attached to the end of cantilever as a sensor.  shpm provides direct quantitative information on the magnetic state of a material and can also image magnetic induction under a...

We analyze the interference between tunneling paths that occurs for a spin system with both fourth-order and second-order transverse anisotropy. Using an instanton approach, we find that as the strength of the second-order transverse anisotropy is increased, the tunnel splitting is modulated, with zeros occurring periodically. This effect results from the interference of four tunneling paths co...