Pressure Dependence of the Magnetic Properties of Mixed-Valence TmSe

Abstract

Measurements of the magnetic moment of TmSe show that the low-field susceptibility and the multiboundary field-temperature ($H_0-T$) phase diagram at low temperatures depend strongly on hydrostatic pressure. For ${\overrightarrow{\mathrm{H}}}_0\parallel \mathrm{}\left[100\right]\mathrm{}$ the upper transition fields increase at a rate ≃ + 1.7 kG/kbar. The magnetic properties reflect the valence changes of ${\mathrm{Tm}}^{2+}$ to ${\mathrm{Tm}}^{3+}$ as the lattice contracts, and for $P\gtrsim 20$ kbar, the Tm ion should be trivalent.