The plasma assisted synthesis and high pressure studies of the structural and elastic properties of metal nitrides XN (X = Sc, Y)

Abstract

ScN and YN crystals were synthesized through the direct nitridation of a metal with nitrogen using a plasma assisted direct current arc discharge method. The structural characterization indicates that the as-synthesized ScN crystals are single crystalline and the YN crystals are polycrystalline with grain sizes ranging from 5–15 nm. The high pressure structural and elastic properties of ScN and YN crystals were investigated using angle dispersive synchrotron radiation in a diamond anvil cell up to 53.9 and 53.5 GPa, respectively. No phase transition occurred in the pressure ranges we achieved in this study, which is in accordance with the theoretical studies that show that ScN and YN are stable under high pressure. The measured zero-pressure bulk modulus for ScN coincides with those of the theoretical results while YN yields a bulk modulus much higher than the theoretical values exhibiting a reduced compressibility. This is considered to be caused by the decreased grain sizes in the characteristic polycrystalline YN.