Spin-orbit coupling results in technologically-crucial phenomena underlying magnetic devices like magnetic memories and energy-efficient motors. In heavy element materials, the strength of spin-orbit coupling becomes large to affect the overall electronic nature and induces novel states such as topological insulators and spin-orbit-integrated Mott states. Here we report an unprecedented charge-ordering cascade in IrTe 2 without the loss of metallicity, which involves localized spin-orbit Mott states with diamagnetic Ir 4 þ -Ir 4 þ dimers. The cascade in cooling, uncompensated in heating, consists of first order-type consecutive transitions from a pure Ir 3 þ phase to Ir 3 þ -Ir 4 þ charge-ordered phases, which originate from Ir 5d to Te 5p charge transfer involving anionic polymeric bond breaking. Considering that the system exhibits superconductivity with suppression of the charge order by doping, analogously to cuprates, these results provide a new electronic paradigm of localized charge-ordered states interacting with itinerant electrons through large spin-orbit coupling.

Molecular quantum magnetism involving an isolated spin state is of particular interest due to the characteristic quantum phenomena underlying spin qubits or molecular spintronics for quantum information devices, as demonstrated in magnetic metal–organic molecular systems, the so-called molecular magnets. Here we report the molecular quantum magnetism realized in an inorganic solid Ba3Yb2Zn5O11 with spin–orbit coupled pseudospin-½ Yb3+ ions. The magnetization represents the magnetic quantum values of an isolated Yb4 tetrahedron with a total (pseudo)spin 0, 1 and 2. Inelastic neutron scattering results reveal that a large Dzyaloshinsky–Moriya interaction originating from strong spin–orbit coupling of Yb 4f is a key ingredient to explain magnetic excitations of the molecular magnet states. The Dzyaloshinsky–Moriya interaction allows a non-adiabatic quantum transition between avoided crossing energy levels, and also results in unexpected magnetic behaviours in conventional molecular magnets.

Thin films of Ga 0.6 Fe 1.4 O 3 show ferrimagnetism with a transition temperature at around 360 K but suffer from large charge conduction. Substituting Fe 2+ with non-magnetic Mg 2+ ions reduces the charge conduction but also lowers the magnetic transition temperature. Doping Ga 0.6 Fe 1.4 O 3 thin films with magnetic Co 2+ ions leads to a similar reduction in the charge conduction, which is significant by two orders of magnitude, and, on the other hand, does not lead to any modification of the ferrimagnetic transition. The remnant magnetization of the leakage currents free Co-doped Ga 0.6 Fe 1.4 O 3 thin films is of 53 emu cm À3 at 300 K. These films, therefore, are promising materials with potential uses in magnetoelectric and multiferroic devices.

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