No abstract

Magnetic properties of inhomogeneous nanoisland FeNi films were studied by SQUID magnetometry. The FeNi films with nominal thickness ranging from 0.6 to 2.0 nm were deposited by rf sputtering on Sitall glass substrates and covered by a protecting Al2O3 layer on the top. The SQUID data indicate pronounced irreversibility behavior for the out-of-plane temperature-dependent magnetization response (measured at H≃100 Oe) using zero-field cooling (ZFC) and field-cooled warming (FCW) after the applied dc magnetizing field Hm≃2 T for the FeNi samples with nominal thickness 1.1 nm ≲d≲1.8 nm, below the percolation threshold. The positive difference between the FCW and ZFC data identifies two irreversibility temperature scales, TB≈50 K and T⁎≈200 K, which can be associated with the superparamagnetic and superferromagnetic behavior in inhomogeneous nanoisland FeNi films, respectively. However, above the film percolation threshold, we observed a crossover from the out-of-plane to in-plane magnetization orientation. Here, the in-plane FCW-ZFC difference implies negative remanent magnetization response in the temperature range TB≲T≲T⁎. The observed magnetization properties can be associated with the presence of the superferromagnetic phase in self-assembled clusters of quasi-2D metallic magnetic FeNi nanoislands.

Imaging of surface plasmon polaritons (SPP's) with a photon scanning tunneling microscope (PSTM) combined with shear force feedback is experimentally investigated. A contrast correction factor, that accounts for spatial frequency filtration performed by an uncoated fiber tip of the PSTM (when detecting the SPP intensity distribution), is introduced and evaluated from the measurements of a standing wave interference pattern formed by two counterpropagating evanescent waves, that are generated by total internal reflection of light beams inside a glass prism. Influence of propagating field components stemming from inelastic SPP scattering on the resultant intensity distributions and, consequently, on the near-field optical images obtained with the PSTM is discussed. Optical images taken at different tip-surface distances are used to evaluate the contribution from propagating field components in near-field optical images taken with shear force feedback. The approach developed is applied to experimental studies of elastic scattering of SPP's excited at the wavelength of 633 nm along smooth and rough surfaces of gold and silver films.

No abstract

Effect of palladium cap layer thickness on desorption of hydrogen from PrH x films: A spectroscopic ellipsometry study J. Appl. Phys. 90, 1795 (2001); 10.1063/1.1385569Determining thickness of thin metal films with spectroscopic ellipsometry for applications in magnetic randomaccess memory Transition from strong to weak electron localization in a percolating gold film under the influence of an electric field Low Temp.