A NUCLEAR ORIENTATION STUDY OF TERBIUM ETHYL SULFATE

Terbium ethyl suphate (TbES) has been studied by nuclear orientation u sing radioactive Tb-160. It is found that (i) it is difficult to cool the terbium nuclei below approximate to 50 mK because of the long nucl ear spin-lattice relaxation time T-1N; (ii) application of small magne tic fields of the order 0.1T produces a dramatic increase in the value of T-1N; (iii) the long electronic relaxation time T-1E makes it diff icult to determine the Curie temperature Te in such experiments; and ( iv) the saturation magnetic moment is approximately 7.35 mu B. No nucl ear magnetic resonance transitions were detected when radio-frequency fields at frequencies from 190 to 920 MHz were applied, but a long ser ies of resonance absorption peaks was observed with a frequency separa tion of 26.3(3) MHz. Their origin is ascribed to magneto-acoustic mode s within magnetic domains, rather than to magnetostatic modes, magneti c spin waves, or resonances within domain walls.