Temperature-dependent 29Si NMR resonance shifts in lightly- and heavily-doped Si:P.

Careful NMR measurements on a very lightly-doped reference silicon sample provide a convenient highly precise and accurate secondary chemical shift reference standard for (29)Si MAS-NMR applicable over a wide temperature range. The linear temperature-dependence of the (29)Si chemical shift measured in this sample is used to refine an earlier presentation of the paramagnetic (high-frequency) (29)Si resonance shifts in heavily-doped n-type silicon samples near the metal-nonmetal transition. The data show systematic decreases of the local magnetic fields with increasing temperature in the range 100-470 K for all samples in the carrier concentration range from 2×10(18) cm(-3) to 8×10(19) cm(-3).

Tilting after Dutch windmills: probably no long-lived Davydov solitons in proteins.

We present a summary of picosecond pump-probe and photon echo experiments in the mid-IR at 6 mum on the protein myoglobin. The intriguing temperature dependence of the amide I band in Mb is rather similar to the temperature dependence of the amide I band of acetanilide, the molecule that launched Al Scott down the road of looking for Davydov solitons in biology. Alas, after much effort, we believe the data show that there is no long-lived Davydov soliton, at least in myoglobin.

Nuclear quadrupole resonance studies of transparent conducting oxides.

We report (63,65)Cu spin-lattice relaxation rates measured by nuclear quadrupole resonance (NQR) in the delafossite compound CuYO(2) and CuYO(2):Ca over a temperature range from 200 to 450K. CuYO(2):Ca is a prototype transparent oxide exhibiting p-type electrical conductivity. Relaxation rates in CuYO(2):Ca are enhanced by one to two orders of magnitude relative to undoped material, exhibit much stronger temperature dependence, and contain contributions from magnetic and quadrupolar relaxation mechanisms with roughly equal strengths.

Nuclear Resonance Properties of YBa2Cu3O6+x Superconductors.

Nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) results for copper-63, oxygen-17, and yttrium-89 nuclei in the superconducting composition range of YBa(2)Cu(3)O(6+x) (0.4 View Article and Find Full Text PDF