Temperature distribution in a solid state NMR sample rotor during MAS experiments.

We investigated temperature distribution in a solid state nuclear magnetic resonance (NMR) sample rotor under magic angle spinning (MAS) experiments by analyzing the (207)Pb chemical shift of solid lead nitrate (Pb(NO3)2). The analysis corrected a mismatch of the temperature dependence of (1)H spin-lattice relaxation time (T1(H)) obtained from different sample positions in the rotor. We prepared three rotors that consisted of Pb(NO3)2 partitioned into the three different parts with Teflon spacers, and measured the temperature distribution related to the placement using the prepared three rotors. The obtained temperature distribution showed a large gradient in the sample rotor. The temperature distribution was related to the placement in the rotor and successfully visualized. Finally, the divergent temperature dependence of T1(H) obtained at different placement positions in the sample rotor was successfully corrected to accurate temperature dependence.