Ultrathin Crystals Research Articles

Abstract: Theory of ferromagnetic resonance and static magnetization in ultrathin crystals

A theory of the static magnetization orientations ϑ0 and of the ferromagnetic resonance fields Hres in ultrathin (50 Å) monocrystalline films is presented. Both ϑ0 and Hres are shown to depend crucially on the magnetocrystalline surface anisotropy, and a generalization of this anisotropy is proposed. The equation-of-motion of the magnetization is combined with the general exchange boundary condition, and realistic approximations are introduced in order to obtain closed algebraic expressions for ϑ0 and Hres. The spatial dependence of the oscillations in the presently calculated resonance modes do not represent spin waves but nondissipative exponential decays perpendicular to the film surfaces. The film thicknesses 2L are so small that the films are ’’beyond spin wave cutoff.’’ It is shown that the angular dependence of Hres differs strongly from that predicted by the uniform mode theory and that Hres is a linear function of 1/L rather than independent of L. An extension of the theory to somewhat thicker films is also presented. A full account of this work has been submitted to Physical Review B.

Low order proton channelling

Computer studies of proton channelling through ultra-thin crystals of gold reveal how to design experiments to measure the potential experienced by the channelling proton and to relate the stopping power to the path of the proton in the channel.

133. The optical constants of graphite in the infrared spectrum determined by transmission through ultrathin crystals

133. The optical constants of graphite in the infrared spectrum determined by transmission through ultrathin crystals

132. The optical constants of graphite in the ultraviolet-visible spectrum determined by transmission through ultrathin crystals

132. The optical constants of graphite in the ultraviolet-visible spectrum determined by transmission through ultrathin crystals