Hyperfine fields at Ga66 , Ge67,69 implanted into iron and gadolinium hosts at 6 K, and applications to

Abstract

Isomers in 66 Ga, 67 Ge, and 69 Ge were recoil-implanted into ferromagnetic hosts of iron and gadolinium at ≈ 6 K, and the hyperfine magnetic fields were determined by Time Differential Perturbed Angular Distribution (TDPAD) measurements. The hyperfine field strengths at ≈ 6 K are compared to the results of previous higher-temperature measurements and the amplitudes of the R(t) functions are compared to empirical expectations. The results show that gadolinium can be a suitable host for high-precision in-beam g-factor measurements. The results of new gfactor measurements for isomers in 66 Ga and 67 Ge are g( 66 Ga, 7 − ) = +0.126(4), supporting a [π f 5/2 ⊗ νg 9/2 ] 7 − configuration assignment, and g( 67 Ge, 9 /2 + ) = −0.1932( 22), derived from a new measurement of the ratio g( 67 Ge)/g( 69 Ge) = 0.869( 9). These values are in agreement with previous results. The R(t) amplitudes indicate that the nuclear alignment produced in the isomeric states was significantly lower than the empirically expected σ/I ≈ 0.35.