Absence of Long-Range Magnetic Ordering in a Trirutile High-Entropy Oxide (Mn$_{0.2}$Fe$_{0.2}$Co$_{0.2}$Ni$_{0.2}$Cu$_{0.2}$)Ta$_{1.92}$O$_{6-δ}$

Gina Angelo; Liana Klivansky; Jeremy G. Philbrick; Tai Kong; Jian Zhang; Xin Gui

paper

Absence of Long-Range Magnetic Ordering in a Trirutile High-Entropy Oxide (Mn $_{0.2}$ Fe $_{0.2}$ Co $_{0.2}$ Ni $_{0.2}$ Cu $_{0.2}$ )Ta $_{1.92}$ O $_{6 - δ}$

arXiv:2405.15501

Abstract

Functionalities of solid-state materials are usually considered to be dependent on their crystal structures. The limited structural types observed in the emerged high-entropy oxides put constraints on exploration of their physical properties and potential applications. Herein, we synthesized the first high-entropy oxide in a trirutile structure, (Mn $_{0.2}$ Fe $_{0.2}$ Co $_{0.2}$ Ni $_{0.2}$ Cu $_{0.2}$ )Ta $_{1.92}$ O $_{6 - δ}$ , and investigated its magnetism. The phase purity and high-entropy nature were confirmed by powder X-ray diffraction and energy-dispersive spectroscopy, respectively. X-ray photoelectron spectroscopy indicated divalent Mn, Co, Ni and Cu along with trivalent Fe. Magnetic properties measurements showed antiferromagnetic coupling and potential short-range magnetic ordering below ~ 4 K. The temperature-dependent heat capacity data measured under zero and high magnetic field confirmed the lack of long-range magnetic ordering and a possible low-temperature phonon excitation. The discovery of the first trirutile high-entropy oxide opens a new way for studying the relationship between the highly disordered atomic arrangement and their magnetic interaction. Furthermore, it provides a new direction for exploring functionalities of high-entropy oxides.

32 pages, 14 figures, 4 tables

Absence of Long-Range Magnetic Ordering in a Trirutile High-Entropy Oxide (Mn0.2​Fe0.2​Co0.2​Ni0.2​Cu0.2​)Ta1.92​O6−δ​

Abstract

Absence of Long-Range Magnetic Ordering in a Trirutile High-Entropy Oxide (Mn $_{0.2}$ Fe $_{0.2}$ Co $_{0.2}$ Ni $_{0.2}$ Cu $_{0.2}$ )Ta $_{1.92}$ O $_{6 - δ}$