The Temperature Dependence of the Magnetic Hyperfine Field at ¹¹¹Cd in Magnetically Ordered Holmium

Abstract

In this letter we report about an investigation of the temperature dependence of the magnetic hyperfine (hf) field acting on ' "Cd impurities in metallic Ho. This study was performed using the time differential perturbed angular correlation (TDPAC) technique (1). Ho has a h.c.p. lattice structure (c/a < 1.633). At low temperatures two phases of spontaneous magnetic order have been found: Up to the Curie temperature TC = 20 K one observes a ferromagnetic screw-type structure, whereas between T and T = 132 K the order of the 4f-moments is of the antiferromagnetic spiral type (2). QIn our experiment solid solutions of metallic Ho and radioactive, carrier-free ' "In were prepared by electron gun melting of the two components. The radioactive -3 impurity concentration was less than 10 at%. A four detector TDPAC apparatus (4) was used to measure the time dependence of the angular correlation of the 173 to 247 keV cascade of 'llCd, which is populated by the EC decay of '"In, as a function of the source temperature. Fig. 1 shows as an example the time spectrum of A G (t), measured at 79 OK. The interaction parameters w B, wQ, and p were 2 22

Exchange Interaction and Hyperfine Fields at Nonmagnetic Impurities in Rare‐Earth Metals

“…8 one may conclude that the helical structure in the matrices of Dy and Ho gives rise to an additional reduction in the conduction-electron polarization in comparison with the polarization in a matrix with collinear ordering of moments, as in the case of Tb. The temperature dependences of hf fields a t lllCd in Dy and Ho [24,25] do not coincide with the matrix magnetization curve either, but in this case the values of deviation differ from those observed for the impurity Sn. h(Z')/m(Z')] for hf fields a t llaSn in I n the Dy matrix, in the region of the transition from ferromagnetism to antiferromagnetism, a jump of the hf field due to Sn is observed a t T,.…”