Hyperfine interactions onCd−probe111nuclei in chromium

Abstract

The hyperfine interactions on $^{111}\mathrm{Cd}$ probe nuclei in a chromium matrix are studied in the temperature range 4.2 to 340 K using time differential perturbed ($\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$) angular correlation of 173-247-keV cascade of $^{111}\mathrm{Cd}$. The cadmium nuclei are found to experience hyperfine fields given by an Overhauser distribution function confirming the existence of the spin-density waves in chromium. The temperature variation of the hyperfine fields clearly displays the first-order N\'eel transition at ${T}_{N}=311$ K and the spin-flip transition at ${T}_{\mathrm{sf}}=123$ K. The data also confirm that the N\'eel transition is a first-order transition. The hyperfine fields measured above and below the spin-flip transition temperature are found to be different, showing that the hyperfine fields are strongly dependent on spin polarization resulting in different net polarized spin density at the probe nucleus above and below ${T}_{\mathrm{sf}}$. In contrast to tantalum impurities, a cadmium probe is found to follow the temperature dependence of the chromium host magnetization faithfully. The data show small but finite texture effects. The observed texture effects probably arise either due to spontaneous partial crystallization of the sample or due to stress-cooling effects on the magnetic structure of chromium. The dilute impurity hyperfine field on $^{111}\mathrm{Cd}$ at 4.2 K in chromium is measured to be 60.3 (\ifmmode\pm\else\textpm\fi{} 2.0) kOe. Systematics of the known dilute-impurity hyperfine-field values in chromium matrix are discussed.