相关论文: Lattice distortion in the spin-orbital entangled s…
We report on a Ni L$_{2,3}$ edges x-ray absorption spectroscopy (XAS) study in $R$NiO$_3$ perovskites. These compounds exhibit a metal to insulator ($MI$) transition as temperature decreases. The L$_{3}$ edge presents a clear splitting in…
Rare-earth titanates RTiO$_3$ are Mott insulators displaying a rich physical behavior, featuring most notably orbital and spin orders in their ground state. The origin of their ferromagnetic to antiferromagnetic transition as a function of…
Time-of-flight inelastic neutron scattering measurements have been carried out on polycrystalline samples of the 4$d^3$ and 5$d^3$ double pervoskite antiferromagnets La$_2$LiRuO$_6$ and La$_2$LiOsO$_6$. These reveal the development of an…
The recent discovery of Spin-ice is a spectacular example of non-coplanar spin arrangements that can arise in the pyrochlore A2B2O7 structure. We present magnetic and thermodynamic studies on the metallic-ferromagnet pyrochlore Sm2Mo2O7.…
We construct and analyze a microscopic model for insulating rock salt ordered double perovskites, with the chemical formula A$_2$BB'O$_6$, where the B' atom has a 4d$^1$ or 5d$^1$ electronic configuration and forms a face centered cubic…
The structural and magnetic properties of YVO3, NdVO3 and TbVO3 were investigated by single-crystal and powder neutron diffraction. YVO3 shows a structural phase transition at 200 K from an orthorhombic structure with the space group Pbnm…
Spin-state crossover beyond a conventional ligand-field theory has been a fundamental issue in condensed matter physics. Here, we report microscopic observations of spin states and low-energy dynamics through orbital-resolved NMR…
Exotic quantum phases, arising from a complex interplay of charge, spin, lattice and orbital degrees of freedom, are of immense interest to a wide research community. A well-known example of such an entangled behavior is the Jahn-Teller…
Rare earth perovskites ($R^{3+}$M$^{3+}$O$_3$), with $e_g^1$ electronic occupation of the M $d$ states, display different types of metal-insulator transition. For manganites (M=Mn), metal-insulator transition is usually induced by the…
We report detailed magnetization measurements on the perovskite oxide NdNiO$_3$. This system has a first order metal-insulator (M-I) transition at about 200 K which is associated with charge ordering. There is also a concurrent paramagnetic…
The unequal electronic occupation of localized orbitals (orbital polarization), and associated lowering of symmetry and degeneracy, play an important role in the properties of transition metal oxides. Here, we examine systematically the…
In this contribution we derive and discuss energy levels of the strongly-correlated d2 configuration of the V3+ ion (LaVO3) and of d4 configuration of the Mn3+ ion (LaMnO3) in the octahedral surroundings in the presence of the spin-orbit…
EuTiO_3 is shown to exhibit novel strong spin-charge-lattice coupling deep in the paramagnetic phase. Its existence is evidenced by an, until now, unknown response of the paramagnetic susceptibility at temperatures exceeding the structural…
Frustrated pyrochlore lattices in transition-metal oxides provide an ideal platform for realizing exotic quantum states, including spin liquids with unconventional low-energy excitations arising from the macroscopic ground-state degeneracy…
Strong spin-lattice coupling and prominent frustration effects observed in the 50$\%$ Fe-doped frustrated hexagonal ($h$)LuMnO$_3$ are reported. A N\'{e}el transition at $T_{\mathrm N} \approx$ 112~K and a possible spin re-orientation…
We report a magnetostriction study of a perovskite $\rm{LaCoO}_{3}$ above 100 T using our state-of-the-art strain gauge to investigate an interplay between electron correlations and spin crossover. There has been a controversy regarding…
First-principles calculations reveal a large cooperative coupling of Jahn-Teller (JT) distortion to oxygen-octahedron rotations in perovskite LaMnO$_3$. The combination of the two distortions is responsible for stabilizing the strongly…
In pursuit of rational control of orbital polarization, we present a combined experimental and theoretical study of single unit cell superlattices of the correlated metal LaNiO$_3$ and the band insulator LaAlO$_3$. Polarized x-ray…
With decreasing temperature Sr$_2$VO$_4$ undergoes two structural phase transitions, tetragonal-to-orthorhombic-to-tetragonal, without long-range magnetic order. Recent experiments suggest, that only at very low temperature Sr$_{2}$VO$_{4}$…
A structural transition in an ABO$_{3}$ perovskite thin film involving the change of the BO$_{6}$ octahedral rotation pattern can be hidden under the global lattice symmetry imposed by the substrate and often easily overlooked. We carried…