Nuclear Spin-Lattice Relaxation of 82BrFe

The field dependence of the nuclear spin-lattice relaxation (SLR) of cold implanted ⁸²Br (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 T²sK⁻¹, r _{∞, 110]} = 5.4(2) · 10⁻¹⁵ T²sK⁻¹ and r _{∞, 111]} = 5.2(1) · 10⁻¹⁵ T²sK⁻¹ were obtained.