Magnetocrystalline phase diagram of Tb: A triple line

Single crystalline terbium was examined employing both uniaxial and hydrostatic pressure. A temperature vs pressure phase diagram was compiled in both cases and, a three-dimensional magnetic phase diagram temperature vs crystalline lattice parameters was established employing a linear approximation. A triple line was obtained which separates paramagnetic, ferromagnetic, and helical antiferromagnetic phases. The temperature range where the helical antiferromagnetic phase exists is a nonlinear function of the strain. The complex magnetic states observed for Tb are interrelated with its band structure and Fermi surface shape.