Magnetization and magnetocrystalline anisotropy of R2Fe17 intermetallics under pressure

The measurements of magnetization and magnetic anisotropy of R2Fe17 (R = Y, Er, Ho, and Gd) single crystals were performed under hydrostatic pressure up to 1 GPa, in temperature range 5-300 K and at magnetic fields up to 5 T, using the SQUID magnetometer with a miniature pressure CuBe cell. A pronou nced decrease of spontaneous magnetization M of the R2Fe17 intermetallics h as been observed under pressure. The values of dM/dp vary in an interval fr om -0.32 mu(B)/f.u. per kbar (Y2Fe17) up to -0.1 mu(B)/f. u. per kbar (Ho2F e17). The R elements in the R2Fe17 intermetallics have a strong influence o n the d(ln m(Fe))/dp values at 5 K. A remarkable decrease of the anisotropy constant with pressure, d ln K-1/dp = -1.7 X 10(-2) kbar(-1) at 5 K, was o bserved on the Y2Fe17 compound. In the Gd2Fe17 compound, \K-1 (T)\ u increa ses with increasing pressure below 150 K and decreases with increasing pres sure above this temperature value. The critical field H-C(T) of the FOMP in the Er2Fe17 compound exhibits a similar behavior, it increases under press ure at temperatures below 60 K and decreases at higher temperatures. (C) 19 99 American Institute of Physics. [S0021-8979(99)59708-9].