Temperature dependence of the Spin-Lattice Relaxation Time
نویسندگان
چکیده
The spin-lattice relaxation time, TX, of the 2 3 N a N M R line in N a N 0 2 is measured between 25 K and 160 K at two magnetic field strengths, 1.1 T and 6.9 T. The temperature dependence of TX for the center line, observed on a polycrystalline sample prepared by precipitation from aqueous solution, is given by a monotonous curve. Tx increases gradually as the temperature decreases. On the other hand for a single crystal, which is made by a modified Bridgman method, the temperature dependence of TX shows two deep dips below 150 K and a frequency dependence which cannot be explained by ordinary BPP theory. The dominant relaxation mechanism above and below 150 K is also investigated.
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