Magnetic properties of double perovskite Ln2CoIrO6 (Ln=Eu, Tb,

Abstract

The field of double perovskites is now advancing to three magnetic elements on the A, B and B sites. A series of iridium-based double perovskite compounds, Ln2CoIrO6 (Ln = Eu, Tb, Ho) with three magnetic elements were synthesized as polycrystalline samples. The compounds crystalize in monoclinic structures with the space group P 21/n. Magnetic properties of these hetero-trispin 3d-5d-4f systems were studied by magnetic susceptibility and field dependent magnetization in both DC and pulsed magnetic fields. All these compounds show ferrimagnetic transitions at temperatures TC above 100 K, which are attributable to antiferromagnetic coupling between Co 2+ and Ir 4+ spins. For Eu2CoIrO6, the magnetic properties are similar to those of La2CoIrO6. The Eu 3+ spins show Van Vleck paramagnetism that don't significantly interact with transition-metal cations. By contrast, Tb2CoIrO6 and Ho2CoIrO6 reveal a second transition to antiferromagnetic order below a lower temperature TN . The temperature-induced ferrimagnetic-to-antiferromagnetic phase transition might be explained by a spin-reorientation transition. Moreover, a magnetic-fieldinduced spin-flop transition with a small hysteresis was observed below TN in these two compounds.The magnetic moment of all three compounds do not saturate up to 60 T at low temperatures. Moderate magnetocaloric effect was also observed in all three compounds. Our results should motivate further investigation of the spin configuration on single crystals of these iridium-based double perovskites.

Behavior of magnetoelectric hysteresis and role of rare earth ions in multiferroicity in double perovskite Yb2CoMnO6

“…Double-perovskite compounds, in which two different transition-metal ions are alternately located in octahedral environments, have been widely investigated. In such materials, combinations of mixed-valence magnetic ions reveal the intricate magnetic interactions and ionic valence/antisite disorders, which enable various fascinating physical properties, such as metamagnetism 8 – 10 , exchange bias 11 – 13 , magnetocaloric effect 14 – 17 , and multiferroicity 18 – 21 . Recent studies have also focused on the potential use of double-perovskite halides in energy devices such as photovoltaic devices 22 – 24 , photocatalysts 25 – 28 , UV detectors 29 , 30 , and solar energy storage 31 , 32 .…”

Influence of the Magnetic Sub-Lattices in the Double Perovskite Compound LaCaNiReO$_6$

“…The magnetic phases of these compounds are controlled both by the magnetic and non-magnetic cations present. More specifically, the sublattice symmetries, the cation's nominal spin and its spin-orbit coupling (SOC) as well as exchange interactions are degrees of freedom that determine the magnetic ground state [10].…”

Distinct magnetic ground states of $R_2$ZnIrO$_6$ ($R$ = La and Nd) determined by neutron powder diffraction

“…For a single magnetic B'/B"-site compound, the superexchange coupling between two nearest cations through intermediate oxygen takes part in the magnetic order. Generally, when the A site is occupied by a magnetic cation, the trivalent lanthanide orders at a lower temperature than the transition-metal sublattice [5,6]. Recently, double perovskites with Ir ions at the B" site have attracted much attention [5,[7][8][9][10][11][12][13] due to the relatively large spin-orbit coupling (SOC) of the Ir 4+ ion which may lead to novel phenomena such as SOC-driven Mott insulator [14] and complex magnetism [15][16][17].…”

“…Generally, when the A site is occupied by a magnetic cation, the trivalent lanthanide orders at a lower temperature than the transition-metal sublattice [5,6]. Recently, double perovskites with Ir ions at the B" site have attracted much attention [5,[7][8][9][10][11][12][13] due to the relatively large spin-orbit coupling (SOC) of the Ir 4+ ion which may lead to novel phenomena such as SOC-driven Mott insulator [14] and complex magnetism [15][16][17]. Some A 2 B'IrO 6 have been synthesized but the magnetic ground states are still not well understood.…”

“…We hope this study motivates others to study Ir 4+ based double perovskites where spin-orbit coupling, on-site Coulomb interaction, and crystal field energies are of comparable energy. For example in Nd 2 ZnIrO 6 the isothermal magnetization curve at 2 K has the signature of a metamagnetic transition at about 2 T which should be studied in more detail, but this is true for many of the iridate based double perovskites [5]. * hjguo@sslab.org.cn Magnetic structure refinement for the La 2 ZnIrO 6 compound according to IR Γ 1 is shown in Fig.…”