59Co NMR from Magnetic Domains in Y2Co14B and Gd2Co14B

NMR measurements have been made for Y 2 Co 14 B and Gd 2 Co 14 B by the steady-state and spin-echo methods in zero external field as a function of temperature. By the steady-state method, the 59 Co domain signals with quadrupole splittings which originate from six non-equivalent Co sites have been observed together with wall signals for the two compounds. It is found that the spin echo peaks generally correspond to wall signals but not to domain signals in these compounds. The hyperfine field at Co nuclei in domains and the spacing between the quadrupole-split component lines for the domain signals are derived. The effect of substitution of Gd for Y on the Co hyperfine field and the magnetic exchange interaction between Co magnetic moments in the compounds is discussed.