TY - JOUR

T1 - High-pressure diamond synthesis in the presence of rare-earth metals

AU - Khokhryakov, Alexander F.

AU - Borzdov, Yuri M.

AU - Kupriyanov, Igor N.

PY - 2020/2/1

Y1 - 2020/2/1

N2 - The effect of rare-earth metals on diamond crystallization processes in the Mg-REM-C system (REM = Sc, Y, La, Pr, Nd, Dy, and Yb) was studied at 7.8 GPa and 1800 °C. It was found that the rare-earth metals added in an amount of 10 wt% had different effects on diamond crystallization. Sc, La, Pr, and Dy, only slightly affected the intensity of diamond synthesis as compared to the undoped Mg-C system. Yb, Y, and Nd significantly reduced the degree of conversion of graphite to diamond. The effect of higher contents of rare-earth metals on diamond crystallization was studied for the Mg-Pr-C system with a Pr content varied from 0 to 80 wt%. It was found that with increasing Pr content the degree of the graphite-to-diamond conversion decreased and at 80 wt% Pr diamond synthesis was terminated and mass crystallization of metastable graphite took place. The morphology of diamonds synthesized in the Mg-REM-C system was determined by the {1 0 0} faces. The surface microrelief of the faces was connected with crystal defectiveness and characterized by specific features, depending on the system composition and the degree of graphite-to-diamond conversion. From the spectroscopic characterization it was found that similarly to their action on diamond synthesis, different REM additives produced different effects on photoluminescence characteristics of the synthesized diamonds. Those rare-earth metals which only slightly affected diamond crystallization, showed no significant effects on the PL spectra relative to the undoped Mg-C system. Diamonds produced with Y, Nd and Yb additives showed a number of new photoluminescence features, which could be related to defects inhibiting diamond crystal growth.

AB - The effect of rare-earth metals on diamond crystallization processes in the Mg-REM-C system (REM = Sc, Y, La, Pr, Nd, Dy, and Yb) was studied at 7.8 GPa and 1800 °C. It was found that the rare-earth metals added in an amount of 10 wt% had different effects on diamond crystallization. Sc, La, Pr, and Dy, only slightly affected the intensity of diamond synthesis as compared to the undoped Mg-C system. Yb, Y, and Nd significantly reduced the degree of conversion of graphite to diamond. The effect of higher contents of rare-earth metals on diamond crystallization was studied for the Mg-Pr-C system with a Pr content varied from 0 to 80 wt%. It was found that with increasing Pr content the degree of the graphite-to-diamond conversion decreased and at 80 wt% Pr diamond synthesis was terminated and mass crystallization of metastable graphite took place. The morphology of diamonds synthesized in the Mg-REM-C system was determined by the {1 0 0} faces. The surface microrelief of the faces was connected with crystal defectiveness and characterized by specific features, depending on the system composition and the degree of graphite-to-diamond conversion. From the spectroscopic characterization it was found that similarly to their action on diamond synthesis, different REM additives produced different effects on photoluminescence characteristics of the synthesized diamonds. Those rare-earth metals which only slightly affected diamond crystallization, showed no significant effects on the PL spectra relative to the undoped Mg-C system. Diamonds produced with Y, Nd and Yb additives showed a number of new photoluminescence features, which could be related to defects inhibiting diamond crystal growth.

KW - A1. Crystal morphology

KW - A1. Impurities

KW - A1. Point defects

KW - A2. Growth from high temperature solutions

KW - B1. Diamond

KW - Point defects

KW - Growth from high temperature solutions

KW - STATE

KW - Diamond

KW - CENTERS

KW - Impurities

KW - 100 FACES

KW - GROWTH

KW - CRYSTALS

KW - Crystal morphology

KW - MORPHOLOGY

UR - http://www.scopus.com/inward/record.url?scp=85075030392&partnerID=8YFLogxK

U2 - 10.1016/j.jcrysgro.2019.125358

DO - 10.1016/j.jcrysgro.2019.125358

M3 - Article

AN - SCOPUS:85075030392

VL - 531

JO - Journal of Crystal Growth

JF - Journal of Crystal Growth

SN - 0022-0248

M1 - 125358

ER -