Measurements of the band gap of ThF4 by electron spectroscopy techniques

We present an experimental determination of the band gap of ThF4 performed by two different techniques. The first measurement was performed by combining x-ray photoemission spectroscopy and bremsstrahlung isochromat spectroscopy. The second measurement exploited the position of the inelastic threshold in reflection electron energy loss spectroscopy. Both measurements gave compatible values of the band gap, with the average E = 10.2(2) eV. This value was found to be in excellent agreement with theoretical calculations. The measured band gap is significantly larger than the 229mTh excitation energy, making ThF4 a possible candidate material for a solid-state nuclear clock based on the vacuum ultraviolet \u3b3 decay

Magnetic and electrical properties of (Pu,Lu)Pd3

We present measurements of the magnetic susceptibility, heat capacity and electrical resistivity of Pu$_{1-x}$Lu$_x$Pd$_3$, with $x$=0, 0.1, 0.2, 0.5, 0.8 and 1. PuPd$_3$ is an antiferromagnetic heavy fermion compound with $T_N=24$~K. With increasing Lu doping, both the Kondo and RKKY interaction strengths fall, as judged by the Sommerfeld coefficient $\gamma$ and N\'eel temperature $T_N$. Fits to a crystal field model of the resistivity also support these conclusions. The paramagnetic effective moment $\mu_{\mathrm{eff}}$ increases with Lu dilution, indicating a decrease in the Kondo screening. In the highly dilute limit, $\mu_{\mathrm{eff}}$ approaches the value predicted by intermediate coupling calculations. In conjunction with an observed Schottky peak at $\sim$60~K in the magnetic heat capacity, corresponding to a crystal field splitting of $\sim$12~meV, a mean-field intermediate coupling model with nearest neighbour interactions has been developed.Comment: 13 pages, 13 figure