Nuclear-Spin-Lattice Relaxation ofV51andTc99in V-Tc Alloys

Abstract

LAMThe spin-lattice relaxation time, T h associated with the V 51 and Tc" nuclei in the V-Tc binary alloy system has been measured over a range of compositions at room, liquid-nitrogen, and liquid-helium temperatures. The quantity T\T (T = absolute temperature) is strongly composition-dependent, but only slightly temperature-dependent, indicating that the predominant relaxation path is via conduction electrons. Of the possible terms contributing to conduction-electron relaxation, that due to the orbital motion of the d-band electrons is believed predominant.

Knight shift, spin-lattice relaxation and electric field gradient in technetium metal

“…The obtained R values were entirely attributed to the spin-orbit interaction, in disagreement with the relevant data for other d-metals [9]. In [5][6][7][8], measurements were done in rather weak magnetic fields (B 0 < 1.4 T) on a wide-line spectrometer with field sweep, which made difficult sufficiently accurate measurement of NMR parameters. Furthermore, nothing was said about the temperature behaviour of the Knight shift and the quadrupole coupling constant.…”

“…Van Ostenburg et al reported C Q = 5.05 MHz, K iso = 6100 ppm and a very small anisotropy K an [6,7]. The spin-lattice relaxation times in technetium metal have been measured at 8 MHz and characterized by the parameter R = (T 1 T ) −1 = 1.56 (s K) −1 at 300 K, 1.25 (s K) −1 at 77.3 K and 1.40 (s K) −1 at 4.2 K [8]. The obtained R values were entirely attributed to the spin-orbit interaction, in disagreement with the relevant data for other d-metals [9].…”

Evolution with Composition of thed-Band Density of States at the Fermi Level in Highly Spin PolarizedCo1−xFexS2Kuhns1, Hoch2, Reyes3 et al. 2006Phys. Rev. Lett.130130View full textAdd to dashboardCite

“…Contact hyperfine interactions due to s electrons are not considered because ionization to form Co 2 removes s states. It is difficult to determine the core polarization contribution 1=T cp 1 reliably but previous work on a variety of systems suggests that this contribution is negligibly small compared to the orbital or dipolar contributions [33,34]. We assume that, for the present highly SP systems, we can neglect this mechanism.…”