Abstract. Double perovskites Sr 2 BOsO 6 (B = Y, In, and Sc) were prepared from the respective binary metal oxides, and their structural, magnetic, and electronic properties were investigated. At room temperature all these compounds crystallize in the monoclinic space group P2 1 /n. They contain magnetic osmium (Os 5+ , t 2g 3 ) ions and are antiferromagnetic insulators with Néel temperatures T N = 53 K, 26 K, and 92 K for B = Y, In, and Sc, respectively. Powder neutron diffraction

Citation for published item:nD finghi nd ulD evijit uumr nd unungoD udipt nd eehuisD wnfred nd roserD endres nd ¤ oensD hniel wF nd hnelleD lter nd illimsD oert gF nd vnsterD om nd ioD pn nd w¤ ollerD tohnnes F nd flundellD tephen tF nd ryesD illim nd pelser D gludi nd tnsenD wrtin @PHIRA 9vttieEsiteEspei( spin dynmis in doule perovskite rPgoysyTF9D hysil review lettersFD IIP @IRAF pF IRUPHPF Further information on publisher's website: eprinted with permission from the emerin hysil oietyX finghi nD evijit uumr ulD udipt unungoD wnfred eehuisD endres roserD hniel wF ¤ oensD lter hnelleD oert gF illimsD om vnsterD pn ioD tohnnes F w¤ ollerD tephen tF flundellD illim ryesD gludi pelserD nd wrtin tnsenD hysil eview vettersD IIPD IRUPHPD PHIRF PHIR y the emerin hysil oietyF eders my viewD rowseD ndGor downlod mteril for temporry opying purposes onlyD provided these uses re for nonommeril personl purposesF ixept s provided y lwD this mteril my not e further reproduedD distriutedD trnsmittedD modi(edD dptedD performedD displyedD pulishedD or sold in whole or prtD without prior written permission from the emerin hysil oietyF Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Magnetic properties and spin dynamics have been studied for the structurally ordered double perovskite Sr 2 CoOsO 6 . Neutron diffraction, muon-spin relaxation, and ac-susceptibility measurements reveal two antiferromagnetic (AFM) phases on cooling from room temperature down to 2 K. In the first AFM phase, with transition temperature T N1 ¼ 108 K, cobalt (3d 7 , S ¼ 3=2) and osmium (5d 2 , S ¼ 1) moments fluctuate dynamically, while their average effective moments undergo long-range order. In the second AFM phase below T N2 ¼ 67 K, cobalt moments first become frozen and induce a noncollinear spin-canted AFM state, while dynamically fluctuating osmium moments are later frozen into a randomly canted state at T ≈ 5 K. Ab initio calculations indicate that the effective exchange coupling between cobalt and osmium sites is rather weak, so that cobalt and osmium sublattices exhibit different ground states and spin dynamics, making Sr 2 CoOsO 6 distinct from previously reported double-perovskite compounds.

Durable multifunctional electrocatalysts with zero emission and high catalytic activity are desirable for environmentally benign clean energy technologies such as water-splitting devices, fuel cells, and rechargeable metal−air batteries. Herein, we investigate a new antisite disordered polycrystalline double-perovskite oxide Ca 2 FeRuO 6 (CFR) material for catalytic activity. This makes it a remarkable electrocatalyst with excellent stability in a highly alkaline (1 M KOH) medium for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). The bulk perovskite exhibits significant onset potentials of 0.9 V for ORR and 1.57 V vs the reversible hydrogen electrode (RHE) for OER, creating a superior bifunctional electrocatalyst. The novelty enhances for trifunctionality as it shows a moderate onset potential of −0.19 V vs RHE for HER. Substantially, the present material efficiently accelerates visible-light-driven water splitting for OER at neutral pH with excellent recyclability. The photo-/electroactive perovskite is an exceptional example of a heterogeneous catalyst for multifunctional activity. A plausible mechanistic pathway for the synergistic effects of e g orbit-filling in perovskite oxides for OER, ORR, and HER activities is proposed by density functional theory (DFT) calculations.

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Using density-functional theory calculations, we investigated the electronic structure and magnetic exchange interactions of the ordered 3d-5d double perovskite Sr2FeOsO6, which has recently drawn attention for interesting antiferromagnetic transitions. Our study reveals the vital role played by long-range magnetic exchange interactions in this compound. The competition between the ferromagnetic nearest neighbor Os-O-Fe interaction and antiferromagnetic next nearest neighbor Os-O-Fe-O-Os interaction induces strong frustration in this system, which explains the lattice distortion and magnetic phase transitions observed in experiments.