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Aluminum alloys 2099-T6 die forgings, 2099-T83 extrusions, 7075-T7651 plate, 7085-T7452 die forgings, 7085-T7651 plate, and 2397-T87 plate were thermally exposed at temperatures of 180 °C (350 °F), 230 °C (450 °F), and 290 °C (550 °F) for 0.1, 0.5, 2, 10, 100, and 1000 h. The purpose of this study was to determine the effect of thermal exposure on the mechanical properties and electrical conductivity of these alloys. The data shows that higher temperatures and longer exposure times generally resulted in decreased strength and hardness and increased percent elongation and electrical conductivity.

The CESR linewidth of pure aluminium is shown to have a temperature dependent phonon contribution which is largely frequency independent. A second term in the linewidth is found to be temperature independent but linearly dependent upon frequency giving 0.11 mT per GHz. Finally it is shown that if partial breakdown of motional narrowing occurs it contributes a term proportional to the frequency and not, as expected, to the frequency squared.

Results are presented of an electron spin resonance (ESR) study carried out at cryogenic temperatures (4.2 K≲T≲35 K) at X‐ and K‐band frequencies of spin‐active defect centers created by ion implantation of 1014 As+ cm−2 at 60 or 80 keV into the SiO2 layer of Si‐SiO2 structures (dSiO2=104–130 nm). Observations were made on single‐crystal boron doped (001) Si wafers of resistivities ρ300 K=0.23 and 22 Ω cm, which had been thermally oxidized. In general, three well‐distinguished centers are observed; two signals, which originate from centers residing in the SiO2 layer, showed typical ‘‘glass’’ pattern line shapes. The first is definitely proven to be the E′ center, which constitutes the first clear experimental evidence of the E′ center in ion‐implanted Si/SiO2 structures. The second signal is shown to correspond very nearly with the ‘‘wet’’ oxygen‐related hole center (OHC) with zero crossing of the derivative spectrum dP/dB given by ga=2.0095. A third previously unreported anisotropic center located at the...

The effect of the observational frequency upon the Conduction Electron Spin Resonance recorded from silver foils and sodium in quartz tubes is reported. For both materials an increase in frequency results in an increase in linewidth, a linear relationship being indicated for silver. We interpret some features of the results as being due to surface effects, additional evidence for the influence of the surface on CESR coming from surface treatment of copper foils.

The influence of ion implantation of 56Fe and 63Cu on the bulk properties of the conduction electrons in aluminium has been investigated with the reflection conduction electron spin resonance (CESR) technique at 21 GHz. The doses were kept low and varied from 3*1013 to 5.4*1014 atoms cm-2. Below 25K, large line broadening and an unexpected g rise has been found in the nonannealed Fe implanted samples, which indicate the existence of surface spins. From the similarity between pure and ion implanted Al it is concluded that surface spins may be important in the so called pure Al too.

The linewidths of the conduction electron spin resonances from high purity aluminium foils and films are measured at frequencies of 9.27 and 20.98 GHz using reflection spectrometers. An attempt is made to fit a breakdown of motional narrowing model to the data. It is found that such a model cannot satisfactorily explain the dependence of the linewidths on frequency, temperature, and sample thickness. Likewise a model based on many-body effects, although explaining some of the features of the results, does not fit all the data. It is possible that a contribution to the impurity induced linewidth which is frequency dependent would provide a better fit and it is concluded that to fully interpret the data a more complex theory is necessary. Leslargeurs de raie des spectres de resonance magnetique des electrons de conduction dans ľaluminium ont ete mesurees a des frequences de 9.27 et 20,98 GHz. Les echantillons etaient sons forme de films ou de couches minces. avec des epaisseurs variant entre 0.8 et 3.8 μm. On a essaye ďexpliquer les resultats par des modeles comprenant les effets de diffusion et ďinteraction d′bechange. Ces modeles ne peuvent pas expliquer toutes les donnees sur la variation des largeurs de raie causee par ľinteraction des electrons avec les impuretes que ľon suppose dependante de la frequence. Ľon peut en conclure qu′une theorie plus complexe est neessaire.

The Hall coefficient and the transverse magnetoresistance in aluminium single crystals were determined from measurements on standing helicon waves, in the three main crystallographic directions [100], [110] and [111]. The magnetic fields ranged from 1 to 7T and the temperature from 4.2 to 20 K. A Legendy-type theory with parameters adapted to the separation of the satellites as measured at high fields gave good fittings over the whole field range. The Hall coefficients, determined in this work, decrease with magnetic field as mentioned in earlier publications, but are generally lower than those published previously for comparable field ranges. The transverse magnetoresistance as a function of temperature was determined from a continuous recording of the helicon response at resonance. The temperature dependent part of the resistivity varies according to a T 3 law for all fields. The field dependence is close to linear, but indications of quadratic and saturation behaviour are also present.

A reinterpretation is presented of recent results (Chizhov et al. 1982) on the conduction electron spin resonance (CESR) linewidths recorded from small lithium particles to which small levels c of sodium impurities have been added. This reanalysis demonstrates good agreement with contemporary understanding of interface spin scattering in bimetallic, layered, systems. It is shown that the sodium segregates out to the surface of the lithium particles. A maximum of three atomic layers of sodium on the surface gives rise to the observed spin-flip probability of the lithium conduction electrons at the surface, ϵ obs , being equal to ϵ Na where ϵ Na is the surface spin-flip probability for the sodium-vacuum interface. We approximate, for sufficient sodium impurities, ϵ obs = ϵ Na to σ sf , Li (Na)/ σ r , Li (Na) where σ sf , Li (Na) and σ r , Li (Na) are the spin-flip and resistivity scattering cross sections respectively for Na impurities in Li. From this relationship it is predicted that the amount of CESR linewidth broadening due to dissolved Na, is ΔB i (Na)/ c = 0.11 mT/at.%.

The exchange parameters and saturation magnetization have been measured for a large number of films of nickel-cobalt alloys. The data are obtained from standing spin wave resonance at room temperature in a conventional 9 GHz spectrometer. The distortions in the spectra are accounted for by a first order perturbation calculation. 1 The results are analysed using a model proposed by Hatherley et al . 2 Within the framework of this model values for the second moment of the exchange integral between NiNi, NiCo and CoCo pairs of atoms are derived.

Polycristalline copper surfaces and germanium single crystals were bombarded with 1000 eV argon ions. The argon ions were produced by means of an electron current between a heated tungsten cathode and an anode at a potential of +300 V. The pressure of the argon gas was maintained at 10−3 mm Hg. The whole system could be evacuated to 10−6 mm Hg with an oil diffusion pump.

The E.S.R. in undiluted single crystals of copper(II) ethylene diamine sulfate has been investigated in the temperature range 300°K–4°K. In the plane perpendicular to the c axis the g-value was isotropic (2.063 ± 0.005) Along the c axis the g-value was 2.276 ± 0.005. The linewidth was found to be isotropic in all the planes investigated. g-factors and linewidth were independent of temperature within experimental error. An unusually high degree of exchange narrowing was also observed.

Conduction-electron spin resonance in thin aluminium platelets, coated with a plastic surface layer, has been studied in a reflection spectrometer at 60 GHz. It is shown that the data on linewidth and g -factor fall in line with recent measurements at 21 GHz by the present authors and partly also with earlier measurements at 1.27 GHz 9.27 GHz, 35 GHz and 79 GHz by others.

The rise in g factor and linewidth with decreasing temperature below 30 K usually observed in CESR of aluminium samples, is almost absent in samples coated with a plastic layer. The properties of untreated samples are slowly restored after removal of the plastic layer. These observations, together with previous results on ion implanted samples, point towards interactions of the conduction electrons with a layer of localized moments on the surface.

In this paper we report the observation of ferromagnetic resonance in nickel at 891 GHz using an HCN laser and pulsed high magnetic fields (up to 35 T). To observe the resonance in a metal we have applied a stripline technique.

The magnetoresistance of single crystal aluminium was measured with the magnetic field in the three main crystallographic directions [100], [110] and [111], in the temperature range 4.2–20 K and in magnetic fields up to 7 T. The exponent of a T n -law is shown to be decreasing with increasing fields.

The electron-electron cross-relaxation rate has the right order of magnitude to explain the variation of linewidth and g factor against temperature of Conduction Electron Spin Resonance in Aluminium at low temperatures.