Accurate measurements of small 31P Knight shift effects in crystalline Ni3P and Cu3P alloys have been performed by using a magic-angle spinning (MAS) nuclear magnetic resonance (NMR) technique. Both the average Knight shift and the width of its distribution have been found to be different when comparing a normal (equilibrium) and a melt-quenched Ni3P alloy and this is attributed to possible differences in defect concentration and grain size. The 31P NMR line shift of Cu3P is much smaller (K=0.012%) than that of Ni3P (K=0.179%) but spin-lattice relaxation time measurements indicated a Korringa-type relaxation mechanism for both alloys, i.e. Cu3P has also a metallic character.

https://iopscience.iop.org/article/10.1088/0953-8984/2/18/018/pdf

31P nuclear magnetic resonance Knight shift and linewidth in Ni3P and Cu3P : a magic-angle spinning study

The magnetic susceptibility χ and the 1H-Knight shift KH of the b.c.c. system Ta1−xTixHy, (0 ≤ x ≤ 0.3, 0 < y ≤ 0.9) was studied by high resolution 1H nuclear magnetic resonance spectroscopy at T = 160°C. Moreover temperature dependent measurements of these properties were carried out for x = 0.0 and x = 0.1 within a temperature range of about 150 K in the α-phase of the alloys. The molar magnetic susceptibility χM(x, y) depends only upon the valence electron concentration and the rigid band model is a very satisfying approximation. On the contrary, the 1H-Knight shift KH(x, y) is strongly influenced by the titanium atoms and the rigid band model fails. The temperature dependence of χ(T) and KH(T) suggest that the Ti-3d-wave-functions produce a negative hyperfine field at the proton sites which differs in sign from that of the Ta-5d-wave-functions. There are pronounced similarities between the systems Ta1−xTixHy, and Nb1−xTixHy.

1H‐NMR Studies of the System Ta1−xTixHy, 0 ≤ x ≤ 0.3, 0 < y ≤ 0.9. Magnetic Susceptibility and Knight Shift

Nuclear magnetic resonance study of the electronic structure and hydrogen diffusion in the random b.c.c. VyTa1−y-H(D) system

Nuclear magnetic resonance study of the electronic structure of TaV2Hx(Dx)

The basic theoretical ideas about the influence of the magnetic susceptibility of the sample material on the nuclear magnetic resonance line position and width of powder samples are discussed Three different effects may occur the respective influence of which could be derived from multiple-pulse line-narrowing experiments with and without rapid magic-angle sample spinning using powder samples mixed from polymer and metal powders Measures to avoid the influence of the susceptibility effects are proposed



Einflus der magnetischen Suszeptibilitat auf Position und Breite von Linien der magnetischen Protonenresonanz in Pulverproben von Ubergangsmetallhydriden



Die theoretischen Grundlagen zum Einflus der magnetischen Suszeptibilitat des Probenmaterials auf Position und Breite von NMR-Linien pulverformiger Proben werden diskutiert Es treten drei unterschiedliche Effekte auf, deren jeweilige Einflusse mit Hilfe von Vielimpulsexperimenten zur Linienverschmalerung mit und ohne schnelle Probenrotation unter dem magischen Winkel zum Bo-Feld an Polymer-Metall-Pulvergemischen bestimmt werden konnten Es werden Wege vorgeschlagen, um den Einflus dieser Suszeptibilitatseffekte zu vermeiden

R. Göring

Papers

Influence of Magnetic Susceptibility on Position and Line-width of Proton Magnetic Resonance Lines in Powder Samples of Transition Metal Hydrides