Effect of pressure on the curie point of Cr 7 □Te 8 with the NiAs‐type structure

Shifts of the Curie temperature of a disordered and an ordered phase in Cr 7 □Te 8 including MLD have been investigated by magnetic induction measurements at hydrostatic pressures up to 5 kbar. The relative magnetization vanishes at the Curie temperature, T C = 343 and 332 °K for the disordered phase (1000 °C) and the ordered phase (400 °C), respectively, at atmospheric pressure. The Curie temperature shifts to lower temperature with increasing pressure at the rate of d T c /d P = −(6.3 ± 0.2) deg/kbarfor Cr 7 □Te 8 (1000 °C) The temperature in parenthesis denotes the quenching one. and d T c /d P = −(5.6 ± 0.4) deg/kbar for Cr 7 □Te 8 (400 °C), determined from magnetic induction measurements. A certain extent difference in pressure effects d T c /d P was observed between the disordered and the ordered phase. This fact implies that the pressure effect on T C is remarkably influenced by the arrangement of MLD in the crystal lattice. The observed difference, Δ T c = 10 deg in the Curie temperature due to a change in the quenching temperature, is explained by the volume effect of exchange interaction in the interatomic spacing. The dependence of nonstoichiometric parameter δ on the exchange mechanisms in Cr 7 □Te 8 is briefly discussed.