Synthesis, characterization, and single-crystal growth of a high-entropy rare-earth pyrochlore oxide

Magnetic properties of high entropy oxides

“…Interestingly, lower temperature alternating current susceptibility measurements, carried at 0.3-1.7 K, indicate spin-glass magnetic ground state of the pyrochlore HEO system. 24 The hexaferrite HEO (P6 3 /mmc) exhibits a ferrimagnetic ordering at room temperature similar to its parent BaFe 12 O 19 , however, magnetic phase separation as observed in P-HEOs is also evident in the hexaferrite HEO. 29…”

“…Apart from R-HEOs, P-HEOs and S-HEOs, magnetic properties of pyrochlore (polycrystalline and also bulk single crystal) 24 , RE based bixbyite 16 and magnetoplumbite-hexaferrite 29 type HEOs are also explored, as summarized in Table 1. Identical to the constituent binary pyrochlore or bixbyite oxides, the pyrochlore (Fd3m) and bixbyite (Ia3) HEOs also exhibit predominant paramagnetic (PM) behavior down to 3 and 5 K, respectively.…”

“…The growing interest in the field of HEOs is illustrated by the numerous studies focusing on their different structural and functional aspects that have already been reported within the five years since their discovery. Currently, there are eight major classes of HEOs that can be categorized based on the crystallographic structures: rocksalt, 1,3,8,9 fluorite, [10][11][12][13][14][15] bixbyite, 10,12,16 perovskite (cubic, orthorhombic, rhombohedral), 5,[17][18][19] spinel, 20,21 pyrochlore, 7,[22][23][24] layered (Ruddlesden-Popper and delafossite) [25][26][27] and magnetoplumbite. 28,29 Likewise, a broad range of properties, such as electrochemical, 2,[30][31][32] optical, 11,[33][34][35] magnetic, 21,29,34,[36][37][38][39][40][41][42]…”

Effects of composition and growth parameters on phase formation in multicomponent aluminum garnet crystals

“…In the case of crystals grown via directional solidification, the formation of a single phase also depends on melt congruency and elemental segregation. While there are several publications on multicomponent oxide thin films (Meisenheimer et al, 2017;Kotsonis et al, 2020Kotsonis et al, , 2018Sivakumar et al, 2018;Liang et al, 2021;Jacobson et al, 2021;Patel et al, 2020;Nguyen et al, 2020;Braun et al, 2018;Sharma et al, 2018Sharma et al, , 2021Chen et al, 2021;Kirnbauer et al, 2019), only a few reports demonstrate the growth and phase formation in multicomponent oxide bulk crystals (Pianassola, Loveday, Chakoumakos et al, 2020;Pianassola et al, 2021;Greculeasa et al, 2020;Liu et al, 2021;Kinsler-Fedon et al, 2020). We previously demonstrated the growth of a six-component aluminum garnet (Lu 1/6 Y 1/6 Ho 1/6 -Dy 1/6 Tb 1/6 Gd 1/6 ) 3 Al 5 O 12 that melted congruently, formed a single phase, and was grown with excellent optical quality and reproducibility (Pianassola, Loveday, Chakoumakos et al, 2020).…”

Synthesis of Pyrochlore Oxides Containing Ir and Ru for Efficient Oxygen Evolution Reaction

“…These oxides possess a crystal framework that is capable of simultaneously accommodating Ir and Ru at the B sites, which strengthens the interaction between local RuO 6 and IrO 6 via shared oxygen and O–A–O bonds [ 17 ]. Furthermore, recent studies have reported the elemental feasibility of forming high-entropy pyrochore oxides by heavy doping of lanthanides on the A site and transition metals on the B site [ 18 , 19 , 20 , 21 ]. In this study, A 2 Ru 2 O 7 and A 2 Ir 2 O 7 , where A is a lanthanide (Pr, Nd, Eu, Gd, Tb, and Ho), are synthesized systematically to confirm the feasibility of synthesis and obtain crystal information.…”