Nuclear Spin-Lattice Relaxation of 82 Br Fe

The field dependence of the nuclear spin-lattice relaxation (SLR) of cold implanted 82 Br ( T ≤ 25 mK) in α-Fe single crystals was investigated with nuclear magnetic resonance of oriented nuclei (NMR/ON) at low temperatures as experimental technique. The SLR at the lattice sites with the hyperfine fields found by earlier NMR/ON experiments was measured as a function of the applied external magnetic field B ext parallel to the three principle axes [100], [110] and [111] of the iron single crystal. The data were evaluated with the full relaxation formalism in the single impurity limit and for comparison also with the often employed model of a single exponential function with an effective relaxation time T 1 ′. With a phenomenological model the high field values of the relaxation rates r ∞, [100]′ = 6.6(2) · 10 −15 T 2 sK −1 , r ∞, [110] = 5.4(2) · 10 −15 T 2 sK −1 and r ∞, [111] = 5.2(1) · 10 −15 T 2 sK −1 were obtained.