Pressure-induced antiferroquadrupole order in CeTe

We have discovered that the magnetic phase diagram of CeTe under high pressure becomes quite similar to that of CeB6, strongly suggesting that an antiferroquadrupolar ordering is realized. At 1.2 GPa, the transition temperature increases from 3 K at 0.5 T to 6.3 K at 14.5 T. Since the crystal-field ground state of CeTe is the Γ₇ doublet without a quadrupolar degree of freedom, this ordering is considered to be realized through the off-diagonal matrix element between Γ₇ and Γ₈ excited state, whose energy level is lowered with increasing the pressure.