The linewidth at 25 GHz of single crystal EuO decreases monotonically from 1200 to 50 Oe in the range 300°K to 2°K. An abrupt narrowing of the linewidth from ∼ 1000 to 100 Oe is observed in the vicinity of the critical point Tc ≈ 70°K, in agreement with the theory of Tomita. © 1968.
