Magnetic phase transitions in R/sub 2/Fe/sub 17/ compounds under pressure

摘要

The effect of the pressure up to 1.4 GPa on the Curie temperature T/sub c/ in the R/sub 2/Fe/sub 17/ intermetallics with R=Nd, Er and Y was measured using a low field susceptibility technique. The identical character of the temperature dependence of susceptibility X(T) of the R/sub 2/Pe/sub 17/ intermetallics observed at ambient pressure (sharp step-like drop at T/sub c/) is preserved at high pressures only in the case of Nd/sub 2/Fe/sub 17/. Pronounced broadening and splitting of the sharp drop of X(T) was observed in Er/sub 2/Fe/sub 17/ and Y/sub 2/Fe/sub 17/ respectively. The initial pressure slopes of dTc/dp are large and negative for all studied compounds, having nearly the same values (dTc/dp=-36K/GPa for Nd/sub 2/Fe/sub 17/ compound). Our results are discussed from the point of view of the sensitivity of T/sub c/ on the crystal structure, the number of nearest neighbours of Fe atoms and the possible effect of "disordered" structures in the R/sub 2/Fe/sub 17/ intermetallics.