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Structures

Materials

Exemplary Phenomena

Layered Perovskite

Iridates (Ir⁴⁺, 5d⁵):

Sr₂IrO₄, Sr₃Ir₂O₇

Doped Sr_n+1Ir_nO_3n+1: 

Dopants on the Sr site: Ca, Ba, Pb, K, and RE;

Dopants at the Ir site: 3d and 4d ions and Tb⁴⁺;

Ruthenates (Ru⁴⁺, 4d⁴): 

Ca_n+1Ru_nO_3n+1,

 Sr_n+1Ru_nO_3n+1 (n=1,2,3,infinite)

(Ca,Sr)_n+1Ru_nO_3n+1

Dopants at the Ru site: 3d, 4d and 5d ions

Iridates: J_eff  = 1/2 insulator; Hidden non-dipolar magnetic order, Lattice-driven magnetoresistance, Giant magnetoelectric effect, Non-Ohmic behavior, Unusual Hall effect, Insulating state highly resistant to high pressures, etc. 

Ruthenates: Orbitally-driven CMR, Bulk spin-valve effect, Orbital order, Oscillatory magnetoresistance periodic in both 1/B and B, Metamagnetism, AFM metallic state, Colossal negative thermal expansion via orbital/magnetic orders, Structurally-driven MIT, AFM, FM, Magnetization reversal, Coexistence of Mott state and quantum oscillations, High sensitivity to modest pressure and electrical-current, etc.

Honeycomb

Lattice

Iridates (Ir⁴⁺, 5d⁵):

Na₂IrO₃, (Li, Na, K)₂IrO_3, 

Na_xIrO₃

Doped Na₂IrO₃: Dopants: RE, Ca, Sr, 3d and 4d ions

Ruthenates (Ru^4+, 4d⁴):

Li₂RuO₃, Na₂RuO₃

Iridates: Zigzag magnetic order, Unusual magnetoelectric effect, Highly frustrated state, etc.

Ruthenates: Lattice-tuned magnetic order. 

Hexagonal peroviskite

Iridates (Ir⁴⁺, 5d⁵):

BaIrO₃, SrIrO₃, (Ba,Sr)IrO₃

Ca₅Ir₃O₁₂, Ca₄IrO₆, 

Doped BaIrO₃ and SrIrO₃: 

Dopants at the Ir sites: 3d and 4d ions

Ruthenates (Ru⁴⁺, 4d⁴): 

BaRuO₃, Doped BaRuO_3, 

Rhodates(Rh^3.5+, 4d⁵, 4d⁶): 

Sr₅Rh₄O₁₂, Ba₉Rh₈O₂₄

Manganites (Mn⁴⁺, 3d³): 

BaMnO_3, doped BaMnO₃

Iridates: J_eff = 1/2 insulator; AFM, Positive and unsaturated magnetoresistivity, Large magnetic coercivity, Non-Ohmic behavior, Magnetic frustration, Quantum critical point, MIT, etc. 

Ruthenates: MIT, Quantum oscillations, etc. 

Rhodates: Spin chains, Partial AFM, low-temperature magnetic order.

Manganites: High-temperature giant magnetoelectric effect coexisting with AFM state.

Pyrochlore

Iridates (Ir⁴⁺, 5d⁵):

Bi₂Ir₂O₇, Pb₂Ir₂O₇

Doped Bi₂Ir₂O₇

Ruthenates (Ru⁴⁺, 4d⁴):

Bi₂Ru₂O₇, Pb₂Ru₂O₇

Iridates: Metallic States; Strong Magnetic Instability, Unusual Field Dependence of Heat Capacity, Unusually Large Wilson Ratio, etc.

Ruthenates: Unusual Metallic States.

Dimer/Trimer Lattice

Iridates (Ir⁴⁺, Ir⁵⁺, Ir⁶⁺): Ba₅AlIr₂O₁₁, Ba₄Ir₃O₁₀, Ba₇Ir₆O_19, Ba₁₃Ir₆O₃₀

New type quantum liquid, AFM insulator, Charge-order-dictated magnetic order.

Double Perovskite

Iridates (Ir⁵⁺, 5d⁴):

Sr₂YIrO₆, Ba₂YIrO₆ Sr₂GdIrO₆, Sr₂CoIrO₆, Sr₂FeIrO₆

Ruthenates (Ru⁵⁺, 4d³):

Sr₂YRuO₆

Iridates: Novel magnetism, AFM metallic state. 

Ruthenates: AFM insulator.