Spin-orbit coupling (SOC) plays a crucial role in magnetic and electronic properties of 5d iridates. In this paper we have experimentally investigated the structural and physical properties of a series of Ir-based double perovskite compounds Pr2-xSrxMgIrO6(x = 0, 0.5, 1; hereafter abbreviated as PMIO, PSMIO1505, and PSMIO). Interestingly, these compounds have recently been proposed to undergo a transition from the spin-orbit-coupled Mott insulating phase at x = 0 to the elusive half-metallic antiferromagnetic (HMAFM) state with Sr doping at x = 1. However, our detailed magnetic and electrical measurements refute any kind of HMAFM possibility in either of the doped samples. In addition, we establish that within these Pr2-xSrxMgIrO6 double perovskites, changes in Ir-oxidation states (4+ for PMIO to 5+ for PSMIO via mixed 4+/5+ for PSMIO1505) lead to markedly different magnetic behaviors. While SOC on Ir is at the root of the observed insulating behaviors for all three samples, the correlated magnetic properties of these three compounds develop entirely due to the contribution from local Ir moments. Additionally, the magnetic Pr3+ (4f(2)) ions, instead of showing any kind of ordering, only contribute to the total paramagnetic moment. It is seen that the PrSrMgIrO6 sample does not order down to 2 K despite antiferromagnetic interactions. But, the d(5) iridate Pr2MgIrO6 shows a sharp antiferromagnetic (AFM) transition at around 14 K, and in the mixed valent Pr1.5Sr0.5MgIrO6 sample the AFM transition is shifted to a much lower temperature (similar to 6 K) due to weakening of the AFM exchange.
Bandyopadhyay, A., Carlomagno, I., Simonelli, L., Moretti Sala, M., Efimenko, A., Meneghini, C., et al. (2019). Evolution of electronic and magnetic properties in a series of iridate double perovskites Pr2-xSrxMgIrO6 (x=0,0.5,1.0) EVOLUTION of ELECTRONIC and MAGNETIC ... ABHISEK BANDYOPADHYAY et al. PHYSICAL REVIEW. B, 100(6) [10.1103/PhysRevB.100.064416].
Evolution of electronic and magnetic properties in a series of iridate double perovskites Pr2-xSrxMgIrO6 (x=0,0.5,1.0) EVOLUTION of ELECTRONIC and MAGNETIC ... ABHISEK BANDYOPADHYAY et al
Carlomagno I.;Meneghini C.;
2019-01-01
Abstract
Spin-orbit coupling (SOC) plays a crucial role in magnetic and electronic properties of 5d iridates. In this paper we have experimentally investigated the structural and physical properties of a series of Ir-based double perovskite compounds Pr2-xSrxMgIrO6(x = 0, 0.5, 1; hereafter abbreviated as PMIO, PSMIO1505, and PSMIO). Interestingly, these compounds have recently been proposed to undergo a transition from the spin-orbit-coupled Mott insulating phase at x = 0 to the elusive half-metallic antiferromagnetic (HMAFM) state with Sr doping at x = 1. However, our detailed magnetic and electrical measurements refute any kind of HMAFM possibility in either of the doped samples. In addition, we establish that within these Pr2-xSrxMgIrO6 double perovskites, changes in Ir-oxidation states (4+ for PMIO to 5+ for PSMIO via mixed 4+/5+ for PSMIO1505) lead to markedly different magnetic behaviors. While SOC on Ir is at the root of the observed insulating behaviors for all three samples, the correlated magnetic properties of these three compounds develop entirely due to the contribution from local Ir moments. Additionally, the magnetic Pr3+ (4f(2)) ions, instead of showing any kind of ordering, only contribute to the total paramagnetic moment. It is seen that the PrSrMgIrO6 sample does not order down to 2 K despite antiferromagnetic interactions. But, the d(5) iridate Pr2MgIrO6 shows a sharp antiferromagnetic (AFM) transition at around 14 K, and in the mixed valent Pr1.5Sr0.5MgIrO6 sample the AFM transition is shifted to a much lower temperature (similar to 6 K) due to weakening of the AFM exchange.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
