Spin -lattice relaxation in solid lead nitrate and other heavy metal salts
Abstract
The spin-lattice relaxation time, T1, for 207Pb in solid lead compounds has been investigated in an effort to understand the mechanism of relaxation. The 207Pb T1 relaxation times for lead nitrate are independent of magnetic field strength and inversely proportional to the square of the temperature. These are signatures of relaxation by a spin-phonon Raman scattering mechanism. We propose a coupling mechanism in which phonons create a local magnetic field by modulating the valence electron shell motion relative to the nuclear/electron core. We also measured the 207Pb spin-lattice relaxation times for lead molybdate, lead tungstate, and a series of BaxPb 1−x(NO3)2 solid solutions and found the T1 times to be proportional to the square of the temperature in all cases. The proposed spin-phonon mechanism should contribute to relaxation in other heavy spin-½ nuclei. We have measured the T 1 relaxation time of 195Pt in potassium hexacyanoplatinate and found that it is also independent of the magnetic field strength and proportional to the square of the temperature, suggesting that the spin-phonon mechanism is the source of relaxation. Literature data suggests that spin-phonon scattering is a common relaxation pathway for 199Hg, 203Tl, and 205Tl as well.
Degree
Ph.D.
Advisors
Grutzner, Purdue University.
Subject Area
Chemistry|Analytical chemistry
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