MEASUREMENTS OF MAGNETIC-SUSCEPTIBILITIES AND ANISOTROPY OF ERBIUM PYROGERMANATE (ER2GE2O7) CRYSTAL

Experimental results of magnetic susceptibilities (K-parallel to, K-pe rpendicular to) and the anisotropy K-parallel to - K-perpendicular to = Delta K of a single crystal of erbium pyrogermanate between 300 K an d 21 K are reported here for the first time. At 300 K, Delta K is 8251 X 10(-6) emu/mole, being 24% of bulk susceptibility (K) over bar and increased by 75 times at 21 K. Crystal field (CF) analysis of the resu lts was made considering D-5h site symmetry. The experimental data wer e best fitted with CF parameters B-20 - 1110, B-40 = 3000, B-60 = -110 0 and B-65 = 600 (all in cm(-1)). The spectral lines for F-4(3/2-9/2), H-2(9/2,11/2) etc. transitions for ErPG were also explained well by t hese parameters. The g values for the Kramers ground state were calcul ated and found to be g(parallel to) = 10.58, g(perpendicular to) = 3.8 2; the saturation magnetization M-sat along and perpendicular to D-5h axis were 686 and 248 emu/cc respectively. The paramagnetic Schottky s pecific heat vs T curve showed a maximum at 110 K. (C) 1998 Elsevier S cience Ltd. All rights reserved.