Nuclear spin lattice relaxation of58CoFe and60CoFe measured by the thermal cycling method

Thermal cycling of thin foil samples is used to measure nuclear spin lattice relaxation of dilute⁵⁸Co and⁶⁰Co in iron at polarizing fields up to 1.3 T. The relaxation rates for the two isotopes differ by a factor of 7.1; the good agreement between the high field values for ² C ₂, (2.93±0.15)·10¹⁵ K·s^–1·T^–2 (⁵⁸Co) and (3.01±0.06)·10¹⁵K·s^–1·T^–2 (⁶⁰Co) verifies the reliability of the experimental method. An enhancement factor model is introduced and shown to give an excellent reproduction of the observed field dependence of the relaxation.