Search

Unlike conventional magnets where the magnetic moments are partially or completely static in the ground state, in a quantum spin liquid they remain in collective motion down to the lowest temperatures. The importance of this state is that it is coherent and highly entangled without breaking local symmetries. In the case of magnets with isotropic interactions, spin-liquid behaviour is sought in simple lattices with antiferromagnetic interactions that favour antiparallel alignments of the magnetic moments and are incompatible with the lattice geometries. Despite an extensive search, experimental realizations remain very few. Here we investigate the novel, unexplored magnet Ca10Cr7O28, which has a complex Hamiltonian consisting of several different isotropic interactions and where the ferromagnetic couplings are stronger than the antiferromagnetic ones. We show both experimentally and theoretically that it displays all the features expected of a quantum spin liquid. Thus spin-liquid behaviour in isotropic magnets is not restricted to the simple idealized models currently investigated, but can be compatible with complex structures and ferromagnetic interactions.

Structurally similar, magnetically diverse: The exchange and Zeeman parameters of two dimetallic, six‐coordinate cobalt(II) compounds—i.e., with orbitally degenerate metal ions—have been determined by a combination of high‐resolution EPR and INS spectroscopies, together with ab intio calculations. It is suggested that the correlation between the local crystal field about the CoIIcenters and the superexchange pathway controls the magnetic interaction.

Strukturell ähnlich, magnetisch verschieden: Die Austausch‐ und Zeeman‐Parameter zweier sechsfach koordinierter Dicobalt(II)‐Verbindungen – mit orbitalentarteten Metallionen – wurden durch eine Kombination aus hochauflösender EPR‐ und INS‐Spektroskopie und Ab‐initio‐Rechnungen bestimmt. Es wird vorgeschlagen, dass die Korrelation zwischen dem lokalen Kristallfeld an den CoII‐Zentren und dem Superaustauschpfad die magnetischen Eigenschaften bestimmt.