Investigation of the temperature and pressure dependence of the electric field gradient of¹¹¹Cd in β-Ce Nd and Y

Abstract

The nuclear quadrupole interaction of dilute 111Cd impurities has been investigated in the rare-earth metals beta -Ce, Nd and Y by time differential perturbed angular correlation measurements. The quadrupole frequency nu Q has been determined in beta -Ce as a function of temperature between 290 K and 25 K, and in Nd and Y as a function of pressure at 290 K. The quadrupole frequency in beta -Ce, which at 290 K is nu Q (111Cd beta -Ce)=12.5(7) MHz, shows a linear temperature dependence between 25 K and 290 K with a slope of (d ln nu Q/dT)290 K=-13.3(9)*10-4 K-1. The pressure coefficient of nu Q of 111Cd in Nd and Y at 290 K is (d ln nu Q/dP)290 K=+6.8(2,5)*10-3 kbar-1 and +16(3)*10-3 kbar-1 respectively. The systematics of impurity quadrupole interactions in rare-earth metals show that the strength and the temperature and pressure dependence of the electric field gradients at impurities in the rare earth are strongly correlated to the number of 4f electrons of the rare-earth ions. Possible mechanisms behind the observed trends are discussed.