Observation of the 169Tm and 27Al NMR in Thulium Aluminum Garnet

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Abstract
The observations of the 169Tm and 27Al nuclear magnetic resonances (NMR) in a single crystal of cubic thulium aluminum garnet are reported. The 27Al MNR was studied between 1.5° and 300°K, while the 169Tm NMR was observed only for T169Tm NMR fields, the (ξ, η, ζ) components of the Tm3+ susceptibility tensor were found to be highly ansiotropic and in units of emu/gram‐atom, χ1=0.014, χ2=0.551, and χ3=0.03. The room temperature 27Al nuclear quadrupolar coupling constants e2qQ/h for the a and d sites were measured to be (0.892±0.005) and (6.155±0.005) MHz, respectively. The 27Al NMR frequency shifts for both sites were found to be angular and temperature dependent. A calculation for the observed angular dependences of the 27Al NMR frequency shifts in terms of dipolar fields is found to give reasonable agreement with experiment for the 1.5° and 300°K NMR data.