Pyrochlore oxides of formula R2M2O7, made of two interpenetrated pyrochlore lattices, are a rich playground in frustrated magnetism to stabilize unconventional magnetic phases, among which classical and quantum spin ice states or dipolar-octupolar phases [1-3]. When the M site is occupied by a magnetic atom such as iridium, it was shown that new magnetic states called fragmented states can...
In the last decade, alpha-RuCl3 has been extensively studied as a possible realization of the Kitaev quantum spin liquid state. However, the Kitaev model alone is insufficient to describe the magnetism in the material, and additional off-diagonal terms and Heisenberg interactions are known to be present. In addition, it is necessary to account for longer-range interactions arising from the...
While the 120 degree antiferromagnetic order is the way of Nature to relieve the frustration of antiferromagnetic interaction on triangular and Kagome lattices and it has been observed in numerous insulating compounds of such lattices, Kagome metals have shown superconductivity and SDW phenomena. When antiferromagnetism in these Kagome metals is induced by doping, collinear antiferromagntic...
The measurement of the magnetic dynamical properties of strongly correlated frustrated spin-liquids presents a significant challenge for neutron scattering instrumentation. Spin-liquids can commonly present spin-fluctuations over a massive dynamical range, strongly correlated in Q-space. In addition, quantum spin-liquid candidate materials have low moments (spin-1/2 or 1) and therefore...
Competing interactions in frustrated magnets can result in highly degenerate ground states from which correlated liquid-like states of matter often emerge. In the extreme quantum limit, these degenerate classical states may evolve into quantum spin liquids. The potential for discovering such exotic phases of matter is one reason that frustrated magnets occupy a major area of quantum...
Transition metal oxides, particularly those with partially filled 3d shells, have been the playground for solid-state physics for many decades. These correlated oxides exhibit a competition between coulombic repulsion, which tends to localize electrons, and hybridization, which promotes delocalization, that leads to numerous many-body effects such as metal-insulator transitions, colossal...
Rhombohedral rare earth ferrites $R$Fe$_2$O$_4$ have a strong tendency for coupled charge (Fe$^{2+/3+}$) and spin order, despite the strong geometrical frustration of the interactions [1]. For $R$=Lu or Yb corresponding superstructure reflections or diffuse scattering appear at ($\frac{1}{3}\frac{1}{3}\ell$). However, the size of Y$^{3+}$ is considerably larger, with calculations [2]...
The study of geometrically frustrated systems with antiferromagnetically (AFM) ordered spins has recently gained considerable attention for their exotic quantum magnetic properties. In order to explore effects related to quantum magnetism we investigate the triangular AFM Na$_2$BaMn(PO$_4$)$_2$, a compound with S=5/2.
By performing single crystal neutron diffraction and theoretical...
i-Tb-Cd orders as icoshedral quasicrystal with the magnetic Tb$^{3+}$ ions arranged in Tsai-type clusters. We studied the magnetic correlations and excitations by elastic and inelastic neutron scattering on single-grain isotopically enriched samples. The measurements of the crystalline-electric field excitations demonstrated that the Tb$^{3+}$ moments are directed along the local fivefold...
Quantum spin liquids with long-range entanglement are of great interest for applications in quantum technology. The quantum spin ice Pr2Zr2O7 is a promising example, where it is believed that structural disorder plays a key role in enhancing quantum mechanical effects by introducing strains that split the ground state doublet akin to the effect of a local...
Compounds in Double perovskites (with general formula A2B’B’’O6) are receiving significant attention in recent research work due to their potential applications in variety of fields [1]. These are derived from simple perovskite structure ABO3 (where A: large electropositive cation and B: small transition metal ion), and possesses diverse chemical and physical properties, ranging from...
