Effects of Sm doping on EuB6

Abstract

A solid-state reaction was used to investigate the nanocrystalline particles of Sm-doped EuB₆ and their optical, thermionic emission and mechanical properties were investigated. The tapered nanoawls had a length of 3–12 μm and a diameter ranging from 40 to 200 nm at the roots and 20–100 nm at the tip as shown by in scanning electron microscopy (SEM). As the temperature of the material increases, the thermionic emission current density also increases. J_o as the zero-field current densities for Eu_0.6Sm_0.4B₆ at 1500 K, 1673 K, 1773 K, 1873 K were 0.72 A cm^-2, 4.25 A cm^-2, 10.06 A cm^-2 and 20.05 A cm^-2. By increasing the Sm doping content, electrical density of Eu_1-xSm_xB₆ decreases. In all materials, the electrical resistivities increased linearly with temperature from 200 to 1200 °C, indicating metallic conductivity. Eu_0.6Sm_0.4B₆ has a lower Vickers hardness and higher flexural strength than EuB₆.