Interplay between the lattice and spin degrees of freedom in(Sr1−xCax)3

Abstract

The ͑Sr 1−x Ca x ͒ 3 Ru 2 O 7 solid solution series exhibits complex magnetic ground states, ranging from an itinerant metamagnetic state, to a quasi-two-dimensional ͑2D͒ heavy-mass nearly ferromagnetic ͑FM͒ state, and finally to a long-range antiferromagnetically ordered state ͓Z. Qu et al. Phys. Rev. B. 78, R180407 ͑2008͔͒. In this paper, we investigate the evolution of structural distortion and magnetic anisotropy with Ca content in this material system. Our results show that both the magnetic phase transitions and magnetic anistropy of this system couple with the evolution of structure distortion. The transformation from the itinerant metamagnetic to the nearly ferromagnetic state is accompanied by an increase in the rotation of the RuO 6 octahedra while the transition from 2D nearly FM state to the antiferromagnetic state coincides with the onset of tilting of the RuO 6 octahedra. Octahedral tilting also causes magnetic anistropy. These results demonstrate that the lattice and spin degrees of freedom are coupled in ͑Sr 1−x Ca x ͒ 3 Ru 2 O 7 .

Hidden phases revealed at the surface of double-layeredSr3(Ru1−xMChen1, Kim2, Nascimento3 et al. 2016Phys. Rev. B91110View full textAdd to dashboardCite

“…LEED is not sensitive to activity beyond the first layer, so it is impossible to determine either the direction or magnitude of the rotational distortion in the second layer. In contrast, distortion of octahedra is observed in bulk structural determinations [26,39] and surely will be present at the surface. If we start with the optimal structure and release our constraints on the surface octahedra we find that with a distorted octahedra R P is slightly reduced and 1 2 θ θ ≠ .…”

“…1(d). Second, we assumed that the second layer rotation has the same magnitude and direction as the first layer [26,39]. LEED is not sensitive to activity beyond the first layer, so it is impossible to determine either the direction or magnitude of the rotational distortion in the second layer.…”

“…Sr 3 Ru 2 O 7 shows metamagnetic quantum criticality under magnetic field [2,4,6], and pressure-induced ferromagnetic (FM) order [23,24]. Doping Sr 3 Ru 2 O 7 with Ca or Mn induces new phases [25,26]. With Ca doping the system goes from itinerant metamagnetic to the AFM phase, accompanied by a transition from metallic to Anderson localized state.…”

“…With Ca doping the system goes from itinerant metamagnetic to the AFM phase, accompanied by a transition from metallic to Anderson localized state. These transitions are associated with the increase of octahedral rotation and onset of tilt [26][27][28][29]. Partial replacement of Ru by Mn leads to a metal-insulator transition (MIT) whose transition temperature T MIT increases with increasing Mn concentration [25].…”

Spin-wave excitation in the antiferromagnetic bilayer ruthenateCa3Ru2O7

“…Likewise, the physical properties of Sr 3-x Ca x Ru 2 O 7 sensitively depend on the Ca concentration [4,15,16,17,18,19,20]. For the end members, Ca 3 Ru 2 O 7 undergoes an antiferromagnetic ordering transition at T N ~ 56 K followed by a first-order metal-insulator transition at T MI ~ 48 K [19], which is dramatically distinct from the paramagnetic behavior observed in Sr 3 Ru 2 O 7 [4].…”