Knight Shifts and Magnetic Susceptibilities in V Alloys with Ti, Cr, and Tc

Ostenburg, D. O. Van; Lam, D. J.; Trapp, H. D.; MacLeod, D. E.

doi:10.1103/physrev.128.1550

Cited by 50 publications

(6 citation statements)

References 13 publications

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“…Depehding on which curves are used, the Knight shift data may be interpreted in a [157], V-Cr [157,158], V-Tc [157], V-Fe [159], V-Ru [160] , V-H [161] , Nb-H [162] , Nb-Tc [163], Zr-Nb and Nb-Mo [164] . (b) Ti-V [165] , V-Cr [157,165], V-Tc [157], Zr-Nb [164], Nb-Mo [163,164] , Nb-Re and Nb-Tc [163]. (c) Ti-V and V-Cr [164 ,166,167] , V-Fe [164], Zr-Nb andNb-Mo [168] .…”

Section: Concentration In Transition Metal Alloysmentioning

confidence: 99%

Relevance of knight shift measurements to the electronic density of states

Bennett

Watson

Carter

1970

J. RES. NATL. BUR. STAN. SECT. A.

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The Knight shift, % , measures th e magne ti c hype rfin e fi eld at th e nucleu s produ ced by th e conducti on e lec tro ns whi c h are po la ri ze d in a ma gne ti c fi e ld. Kni ght s hifts are ofte n dominated by th e Pauli term a nd , in it.s mo st s impl e form , can be writte n as % = (a) x p. H ere XP is the conduction electron Pauli s pin s usce ptibility whic h de pe nd s on th e de nsity of states at th e Fe rmi le vel, N(EF), and (a ) is an a ve rage magneti c hype rfin e couplin g' cons tant associated with th e wav e function characte r at the nu c le us, 1

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Section: Concentration In Transition Metal Alloysmentioning

confidence: 99%

Relevance of knight shift measurements to the electronic density of states

Bennett

Watson

Carter

1970

J. RES. NATL. BUR. STAN. SECT. A.

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“…Both methods indicate the same result, namely, a speed of plasma expansion of about 10 4 cm sec" 1 . In contrast, the calculated wave velocity for the propagation of electroacoustic waves in the plasma would be about 10 6 cm sec" 1 .…”

mentioning

confidence: 68%

“…Figure 1 shows a plot of the room-temperature magnetic susceptibility as a function of Tc content for the ternary alloys and for the alloys of the V-Tc binary system. 1 In both cases the susceptibility decreases with increasing Tc concentration and has a very small temperature dependence. Figure 2 shows the Knight shifts of the three nuclear species in the ternary alloys.…”

mentioning

confidence: 93%

Knight ShiftsKV,KTc, and
Ostenburg
¹
,
Lam
²
,
Trapp
³

et al. 1963
Phys. Rev. Lett.
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the delay in response between a pair of probes and the other on the time that elapsed before each individual probe responded. Both methods indicate the same result, namely, a speed of plasma expansion of about 10 4 cm sec" 1 . In contrast, the calculated wave velocity for the propagation of electroacoustic waves in the plasma would be about 10 6 cm sec" 1 .The evidence for the slow expansion of the plasma column rests solely on the probe signals. Such slow motion in the absence of an external magnetic field has been unknown hitherto, so it is natural to suspect the probes. There is no evidence as yet to support this suspicion: For example, in one run during which the probes responded at different times as usual, there was subsequently a break in the discharge currentIn bcc V-Tc-Al alloys the conduction electrons of V and of Tc form a common band, according to measurements of the magnetic susceptibility and nuclear magnetic resonance of the alloys, whereas the conduction electrons of the Al interact but little, if at all, with those of the transition elements. For the V and Tc these results agree with the previously reported behavior of bcc binary alloys of V with other transition metals 1 of the first and second long periods. Since the composition dependence of the Knight shift and magnetic susceptibility of these binary alloys depend essentially on the electron/atom ratio rather than on the alloying species, these elements appear to conform to the rigid-band model; that is, the number of electrons in the band of an element in the periodic table is simply increased or decreased by alloying with a neighboring element without appreciably affecting the band structure. Measurements of low-temperature specific heats 2 and of superconductive transition temperature 3 likewise imply applicability of the rigid-band model to bcc alloys of the first and second long-period transition elements.On the other hand alloying V with nontransition elements, 4 such as Al or Si, changes the which was not maintained. The collection of current by all the probes then ceased simultaneously.At this preliminary stage of the investigation it would be premature to offer an explanation of the slow expansion. However, it is certain that it is not an aerodynamic effect related to the ejection; the neutral particles reached the ionization gauge much more quickly than the charged particles reached probes situated closer to the exposed plasma column than the gauge. It is possible that the effect is associated with the stability of the plasma sheath and that some form of electrostatic confinement retards the motion of the plasma.A more detailed account has been submitted for publication elsewhere.picture. For example, in the V-Al binary bcc system, the V 51 shift increases only slightly from 0. 56% in pure V to 0. 58% at 40 at.% Al in V, and the change is nearly linear with Al content. The Al 27 shift is negative and nearly independent of concentration within experimental error, with a value in the vicinity of -0.03%. This is to be contrasted with t...

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“…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.…”

Section: Introductionmentioning

confidence: 82%

“…They determined the isotropic Knight shift K iso = 7150 ppm, anisotropy of this shift K an = 1150 ppm, linewidth of the central component H pp = 13 Gs and C Q = 5.716 MHz at zero asymmetry parameter of the electric field gradient (EFG) tensor by analysing the lineshape for a Tc powder as a function of resonance frequency (3.2-10.2 MHz). 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].…”

Section: Introductionmentioning

confidence: 99%

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

Тарасов

Muravlev

Guerman³

2001

J. Phys.: Condens. Matter

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Spin-lattice relaxation time (T 1), isotropic Knight shift (K iso) and quadrupole coupling constant (C Q) have been measured in technetium metal by pulsed 99 Tc NMR in a magnetic field of 7.04 T in the temperature range 120-400 K. It was found that (T 1 × T) −1 = 3.21 ± 0.35 (s K) −1 , K iso (T) = 7305 − 1.52T ppm; the quadrupole coupling constant C Q = 5.74 ± 0.05 MHz is temperature independent. Experimental data on T 1 and K iso are analysed in terms of the contact, d-polarization and orbital hyperfine interactions. It is shown that the main contribution to the relaxation rate comes from the contact interaction and the Knight shift is governed by the orbital interaction. The electric field gradient at 99 Tc nucleus site is considered to be a sum of the electron q el and lattice q lat contributions with different signs. The calculated lattice contribution is positive and constitutes about 30% of the electronic contribution. The obtained values of q el and q lat are compared with data for other metals with hexagonal closepacked lattices.

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Knight Shifts and Magnetic Susceptibilities in V Alloys with Ti, Cr, and Tc

Cited by 50 publications

References 13 publications

Relevance of knight shift measurements to the electronic density of states

Relevance of knight shift measurements to the electronic density of states

Knight ShiftsKV,KTc, and
Ostenburg
¹
,
Lam
²
,
Trapp
³

et al. 1963
Phys. Rev. Lett.
Self Cite

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

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Knight Shifts and Magnetic Susceptibilities in V Alloys with Ti, Cr, and Tc

Cited by 50 publications

References 13 publications

Relevance of knight shift measurements to the electronic density of states

Relevance of knight shift measurements to the electronic density of states

Knight ShiftsKV,KTc, andOstenburg1, Lam2, Trapp3 et al. 1963Phys. Rev. Lett.Self Cite

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

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About

Knight ShiftsKV,KTc, and
Ostenburg
¹
,
Lam
²
,
Trapp
³

et al. 1963
Phys. Rev. Lett.
Self Cite