X-ray magnetic circular dichroism (XMCD) measured at T=6$\hskip0.3em${}K and $\mu${}0H=5$\hskip0.3em${}T on the $\alpha${}-phase Fe-phthalocyanine (FePc) textured thin films shows that the Fe2+ ions present an unusually large, highly unquenched mL=0.53\ifmmode\pm\else\textpm\fi{}0.04$\hskip0.3em${}$\mu${}B orbital component, with planar anisotropy. The spin mS=0.64\ifmmode\pm\else\textpm\fi{}0.05$\hskip0.3em${}$\mu${}B and the intra-atomic magnetic dipolar mT components were also obtained. The mL/mS=0.83 ratio is the largest measured in 3d complexes and compounds. The origin of this unusually high orbital moment is the incompletely filled eg level lying close to the Fermi energy. This explains the unusually large and positive hyperfine field detected by M\"ossbauer spectroscopy in FePc. The FePc film strong planar anisotropy inferred from XMCD experiments is fully confirmed by magnetization measurements.

Magnetic properties of Au nanoparticles deposited on an archaeal S layer are reported. X-ray magnetic circular dichroism and superconducting quantum interference device magnetometries demonstrate that the particles are strongly paramagnetic, without any indication of magnetic blocking down to 16~mK. The average magnetic moment per particle is Mpart=2.36(7) $\mu${}B. This contribution originates at the particle's Au 5d band, in which an increased number of holes with respect to the bulk value is observed. The magnetic moment per Au atom is 25 times larger than any measured in other Au nanoparticles or any other configurations up to date.

We have investigated the spin and oxidation states of Co in ${\mathrm{Co}}_3{\mathrm{BO}}_5$ using x-ray magnetic circular dichroism (XMCD) and dc magnetic susceptibility measurements. At low temperatures, XMCD experiments have been performed at the Co $K$-edge in ${\mathrm{Co}}_3{\mathrm{BO}}_5$ and ${\mathrm{Co}}_2{\mathrm{FeBO}}_5$ single crystals in the fully ferrimagnetically ordered phase. The Co ($K$-edge) XMCD signal is found to be related to the ${\mathrm{Co}}^{2+}$ magnetic sublattices in both compounds, providing strong experimental support for the low-spin (LS) ${\mathrm{Co}}^{3+}$ scenario. The paramagnetic susceptibility is highly anisotropic. An estimation of the effective magnetic moment in the temperature range 100–250 K correlates well with two ${\mathrm{Co}}^{2+}$ ions in the high-spin (HS) state and some orbital contribution, while ${\mathrm{Co}}^{3+}$ remains in the LS state. The crystal structure of the ${\mathrm{Co}}_3{\mathrm{BO}}_5$ single crystal has been solved in detail at the $T$ range 296–703 K. The unit cell parameters and volume show anomalies at 500 and 700 K. The octahedral environment of the Co4 site strongly changes with heating. The generalized gradient approximation with Hubbard $U$ correction calculations have revealed that, at low-temperatures, the system is insulating with a band gap of 1.4 eV, and the ${\mathrm{Co}}^{2+}$ ions are in the HS state, while ${\mathrm{Co}}^{3+}$ are in the LS state. At high temperatures ($T$ > 700 K), the charge ordering disappears, and the system becomes metallic with all Co ions in $3d^7$ electronic configuration and HS state.

Two new neodymium molecular magnets of formula {[Nd(α-fur) ₃ (H ₂ O) ₂ ]·DMF} _n ( 1 ) and {[Nd _0.065 La _0.935 (α-fur) ₃ (H ₂ O) ₂ ]} _n ( 2 ), α-fur = C ₄ H ₃ OCOO, have been synthesized and characterized.