GdBO$_3$ and YBO$_3$ Nanocrystals under Compression

TL;DR

This study provides new high-pressure X-ray diffraction data on GdBO$_3$ and YBO$_3$ nanocrystals, revising their bulk moduli and compressibility behavior, and highlights potential errors in previous research.

Contribution

The paper offers the first accurate pressure-volume equations of state for GdBO$_3$ and YBO$_3$ nanocrystals, correcting earlier overestimations of their bulk moduli.

Findings

Bulk moduli are approximately 50% smaller than previous reports.

Results align with known borate systematics and ab initio calculations.

Highlights importance of experimental accuracy in high-pressure studies.

Abstract

High-pressure X-ray diffraction studies on nanocrystals of the pseudo-vaterite-type borates GdBO$_3$ and YBO$_3$ are herein reported up to 17.4(2) and 13.4(2) GPa respectively. The subsequent determination of the room-temperature pressure-volume equations of state is presented and discussed in the context of contemporary publications which contradict the findings of this work. In particular, the isothermal bulk moduli of GdBO$_3$ and YBO$_3$ are found to be 170(13) and 163(13) GPa respectively, almost 50% smaller than recent findings. Our experimental results provide an accurate revision of the high-pressure compressibility behaviour of GdBO$_3$ and YBO$_3$ which is consistent with the known systematics in isomorphic borates and previous ab initio calculations. Finally we discuss how experimental/analytical errors could have led to unreliable conclusions reported elsewhere.