The magnetic after‐effect spectrum in cobalt between 20 and 350 K after electron irradiation at 4.2 K

Abstract

After electron irradiation of cobalt single crystals a spectrum of magnetic after-effect processes is observed where nearly all the relaxation peaks anneal out rapidly during the measurement. For the discussion of the experimental results a survey is given of the configurations of interstitial atoms and close Frenkel pairs which can be expected for the h.c.p. lattice. Taking into account resistivity annealing experiments the relaxation process at 325 K can be attributed to a diffusion after-effect which is due to a freely migrating defect.Nach Elektronenbestrahlung von Kobalteinkristallen wird das Nachwirkungsspektrum zwischen 20 und 360 K untersucht. Nahezu alle in diesem Temperaturbereich untersuchten Nachwirkungsprozesse heilen wiihrend der Messung aus. Zur Diskussion der experimentellen Ergebnisse wird eine vbersicht iiber die Konfigurationen von Zwischengitteratomen und engen Frenkelpaaren gegeben, die im hexagonal dichtest gepackten Gitter moglich sind. Unter Berucksichtigung gleichzeitig durchgefiihrter Widerstandsmessungen kann der NachwirkungsprozeB bei 325 K einer Diffusionsnachwirkung durch frei wandernde Fehlstellen zugeschrieben werden.

Electrical resistivity recovery of cobalt after low‐temperature electron irradiation

“…One can therefore assume that in stage I11 freely migrating defects are involved. This interpretation is supported by our magnetic aftereffect ineasurenients [8] which show that the defects annealing out in stage I11 give rise to a diffusion aftereffect. From our present results we cannot decide whether stage I11 in Co can be attributed to interstitial [19] or vacancy [13,20] migrat,ion, which both can give rise to a diffusion aftereffect.…”

“…This can easily be understood, if one considers the great variety of Frenkel pairs which may exist in the h.c.p. lattice The interpretation of the recovery spectrum between 20 and 55 K by annealing of close Frenkel pairs is also suggested by our magnetic aftereffect measurements [8], with a number of relaxation processes in this temperature range which anneal out during measurement with a very few jumps of the defects involved.…”

“…The complex structure of the recovery spectra may be due to the great number of defect configurations (interstitials and Frenkel pairs), which is to be expected for hexagonal metals [8], but it may also be influenced by the rather high impurity contents of the present Co samples.…”