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Ferromagnetic resonance experiments of magnetic nanostructures over a large frequency range from 1 to 225 GHz are presented. We find unambiguous evidence for a nonlinear frequency dependence of the linewidth. The viscous Gilbert damping and two-magnon scattering are clearly separated. Both angular and frequency dependent measurements give a transverse scattering rate within the magnetic subsystem of the order of 10 9 s −1 , whereas the longitudinal Gilbert relaxation into the thermal bath is one to two orders of magnitude smaller.

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The transmission-electron-spin resonance (TESR) is measured on copper foils with ferromagnetic films of permalloy, iron, and nickel deposited on one surface. The greatly enhanced TESR resulting from the presence of the ferromagnetic film is studied as a function of orientation of the magnetic field which tunes the relative resonance frequencies of the ferromagnetic resonance (FMR) mode and the pure-copper TESR modes over a wide range. A phenomenological theory is developed from appropriate Bloch equations for the copper and for the ferromagnetic film, coupled by the transport of magnetization by the diffusion of electrons across the interface between the two metals. This theory describes well a number of distinct features of the experimental results. 19O1979 The American Physical Society COUPLING 9ET%EEN FERROMAGNETIC AND CONDUCTION. . . J 4383 planted ions. In the simpler cases, the analysis has been done by Hurdequint'and Walker" and can be sketched in the following manner: the eigenmode for resonance of the conduction-electron spin is identical to that of a very dilute homogeneous alloy containing the same number of magnetic ions (except for the diffusion coefficient). However the response of that mode to rf excitation is that of the implanted layer which will be much more strongly coupled than the pure metal, due to the greatly enhanced susceptibility. This results mainly in an appreciable gain in signal intensity, together with a shift and linewidth increment, due to the coupling of the electrons spins to the ions.

The structure and electronic properties of potassium-doped single-wall carbon nanotubes have been studied by conduction electron spin resonance, conductivity (), and x-ray diffraction ͑XRD͒, using in situ electrochemical methods. The spin susceptibility P of the K-saturated phase is independent of temperature; a lower bound is 5ϫ10 Ϫ8 emu/g. At 300 K both and P increase monotonically and reversibly with K/C. The spin relaxation rate and g factor do not change with doping, and XRD reveals an irreversible loss of crystallinity upon doping. We propose an inhomogeneous doping model to explain these results. RAPID COMMUNICATIONS R4846PRB 62 CLAYE, NEMES, JÁ NOSSY, AND FISCHER RAPID COMMUNICATIONS R4848PRB 62 CLAYE, NEMES, JÁ NOSSY, AND FISCHER

Single crystals of a linear cycloadduct conducting polymer, (KC(60))n, have been grown that are a few tenths of a millimeter in length. Partial oxidation under toluene transformed these crystals into bundles of fibers. The degree of polymerization exceeded 100,000.

High filling of single wall carbon nanotubes (SWCNT) with C60 and C70 fullerenes in solvent is reported at temperatures as low as 69 o C. A 2 hour long refluxing in n-hexane of the mixture of the fullerene and SWCNT results in a high yield of C60,C70@SWCNT, fullerene peapod, material. The peapod filling is characterized by TEM, Raman and electron energy loss spectroscopy and X-ray scattering. We applied the method to synthesize the temperature sensitive (N@C60:C60)@SWCNT as proved by electron spin resonance spectroscopy. The solvent prepared peapod samples can be transformed to double walled nanotubes enabling a high yield and industrially scalable production of DWCNT.