Dynamic Ferrimagnetic Order in a Highly Distorted Double Perovskite Y₂CoRuO₆

Abstract

Y2CoRuO6 was synthesized as a B-site ordered double perovskite with distorted monoclinic P21 /n symmetry and an average tilting of the CoO6 and RuO6 octahedra of ψ̅ = 19.7°. DC magnetization measurements show a ferrimagnetic transition at around 82 K. Although long-range ferrimagntic order is supported by neutron diffraction studies, aging phenomena in time-dependent isothermal magnetization, frequency dependence of AC susceptibility, and a smeared peak in the specific heat together reveal spin glass-like dynamics. The magnetic subtleties resemble chaotic behavior as previously observed in some ferro- or ferrimagnetic materials that exhibit spin glass-like dynamics. It is argued that the magnetic dynamics in Y2Co­RuO6 mainly stem from competition between antiferromagnetic Co↑-O-(Ru)-O-Co↓/​Ru↑-O-(Co)-O-Ru↓ and antiferromagnetic Co↑-O-Ru↓ interactions, besides a degree of Co:Ru antisite disorder. Herein, the B-site ordered Y2Co­RuO6 offers a model to explore the intriguing dynamics in correlated 3d–4d transition metal double perovskites.

A Pressure‐Induced Inverse Order–Disorder Transition in Double Perovskites

“…YCRO-0G is isostructural to YCIO-0G with s YCRO-0G = 0.84, consistent with previous report. [28] In contrast, in the inset of Figure 1a the extinct (011) peak on the PXD pattern of YCRO-15G implies complete B-site disorder.R ietveld refinement indicates that YCRO-15G is isostructural to YCIO-15G (Table 1a nd Figure 1d). Thel attice volume V = 225.112 3 is substantially smaller than that of YCRO-0G (V = 227.198 3 ).…”

“…Thel attice volume V = 225.112 3 is substantially smaller than that of YCRO-0G (V = 227.198 3 ). [28] Thed egrees of B-site order significantly influence the magnetic behaviors of both YCIO and YCRO. Similar to previous studies magnetic frustration, which is induced by the B' À B'' antisite, [24,27,32] weakens long-range magnetic ordering in B-site ordered DPs.T emperature-dependent magnetization (M(T)) in Figure 2a shows that af erromagnetic (FM)like phase transition occurs in YCIO-0G upon cooling down.…”

“…Theformer is anew DP while the ordered phase of the latter was recently reported. [28] In YCIO the ordering degree decreases form s = 0.854 for ambient pressure synthesized sample (YCIO-0G) to s = 0.454 for sample synthesized at 6GPa (YCIO-6G), and finally to s = 0f or sample synthesized at 15 GPa (YCIO-15G). For YCRO s changes form 0.84 of ambient pressure sample (YCRO-0G) to 0o f1 5GPa one (YCRO-15G).…”

Octahedral tilting and emergence of ferrimagnetism in cobalt-ruthenium based double perovskites

“…As already mentioned, a transition from AFM to FI via a glassy magnetic state has been observed in several double perovskites with the bending of the B-O-B ′ bond [8][9][10]13 , where the lattice distortion was created by systematic doping at the A site or by applying hydrostatic pressure. In the present case, we found similar effect when one rare-earth ion is replaced by another one with smaller ionic radius.…”

“…The ∆S M versus T data depicted in fig.4 show peak like anomalies between 8 and 12 K in PCRO, NCRO and SCRO , and they can be probable ordering points of rare-earth moments. In order to shed more light on this issue, we have compared the moments of A 2 CoRuO 6 (A = Pr, Nd, Sm and Y), where the magnetic data of Y 2 CoRuO 6 is obtained from reference 13 . The moments at 5 K (M 5K ), on applying 50 kOe of field, is found to be 2.3, 2.9, 1.4 and 0.8 µ B /f.u.…”