Effect of pressure on the Fermi surface and band structure of ferromagnetic Gd. I. Experiment

We report measurements of the effect of pressure on eight cross sections of the Fermi surface of ferromagnetic Gd. Cross sections were obtained from de Haas-van Alphen effect measurements on a spherical crystal cut from a boule refined by electrotransport to a residual resistivity ratio of {~}260. Pressure derivatives were determined using both fluid-He and solid-He techniques. The results show a surprising variation in both sign and magnitude in view of the near isotropy of the linear compressibilities of Gd. An electron transition involving the disappearance of a cross section of the Fermi surface near 8 kbar is indicated.