Magnetic Resonance in Dysprosium Metal

Abstract

Magnetic resonance has been observed at 37.7 Gc/sec in a hexagonal platelet of dysprosium metal at temperatures in the range where the spin arrangement is spiral. The resonance behavior is in many respects similar to that observed near the spin-flop field in ordinary antiferromagnets. The temperature dependence of the field for resonance generally follows the temperature dependence of the critical field for the transition from spiral to ferromagnetic spin arrangement. Widths on the order of 1 kOe were observed for the dc field applied along both easy and hard axes of the planar anisotropy. A secondary absorption peak is resolved at a field about 400 Oe higher than the field for the main resonance for temperatures below 106°K with the dc field along an easy axis and below 120°K with the dc field along a hard direction. The planar anisotropy becomes insignificant above the latter temperature. The detailed interpretation of line shapes is complicated by changes in the conductivity occurring at the critical field.