PIXE and magnetic investigations of LaxRE1-x F3 (RE = Ce,Nd) single crystals

The mixed LaxRE1-xF3 single crystals doped with Gd3+ were grown by a modified Bridgmann- Stockbarger method. The PIXE method was used to the determination of a composition x of this material. The value of x for these samples does not differ more than 2.5 percent and 7.5 percent in LaxCe1-xF3 and LaxNd1-xF3 respectively, from the assumed one. In addition, concentrations of the doped rare earth atoms were controlled by XRF method. The abundance of other than Gd3+ rare earth impurities was estimated to be below 0.058 at percent. The magnetic susceptibility of the single crystals was measured in the temperature range 4-300 K, in a magnetic field B equals 0.2 T applied in the crystallographic plane perpendicular to the c-axis using the Faraday method. The magnetic susceptibility measurements confirm the lack of Ce3+ and Nd3+ clusters in the diluted crystals. The effective spins of hosts Ce3+ and Nd3+ are equal to ½ in the temperature range 4-300 K.