Diamagnetic Domains In Beryllium Observed By Muon-Spin-Rotation Spectroscopy

Dia- and paramagnetic (Condon) domains were observed in single crystal beryllium for applied fields H parallel to[0001] of 1-3 T, at temperatures T = 0.1-3 K, by muon-spin-rotation (mu SR) spectroscopy at PSI. On varying H, the domains with magnetization parallel and opposite to H reappear in each de Haas-van Alphen period Delta H, detected by the doubler splitting in the precession frequency spectrum. As H varies within the "domain section" SH of a dHvA cycle, the domain inductions B-1,B-2 stay constant, while the volume fractions of the para- and diamagnetic regions vary linearly. The beat in the susceptibility amplitude a(B) = 4 pi(dM/dB)(max), with a period of approximate to 33 . Delta H, allowed us to determine B-i and delta H for different regimes. As a increases by a factor of approximate to 3, the sections delta H grow, \B-2-B-1\-->Delta H, and the uniform state between two domain sections shows an increasingly strong diamagnetism, - 4 pi chi much greater than 1. The domains persist up to T approximate to 3 K and at fields down to H approximate to 1 T On varying H, a slight ''field overheating'' was observed. The domain area in the phase diagram is much larger than expected, while other predictions of the theory proved to be qualitatively correct. [S0163-1829(99)03509-2].