Predesigned rigid dysprosium(III) single-molecule magnets exhibit preserved superparamagnetism in solution

Molecules with long preserved magnetic moments are perceived as the smallest units for storing bytes, which could bring a new revolution for information technology. However, the rational design of such molecules remains challenging. Here we show it is possible to predesign such molecules by studying the vibration spectra. Two adamantanol based dysprosium(III) complexes with pentagonal-bipyramidal local geometry were theoretically predicted to display enhanced single-molecule magnet (SMM) behavior due to the reduced vibration modes in low energy regimes. The experimental isolation of these two complexes not only confirms this prediction, but further reveals almost unchanged large energy barriers and high blocking temperatures in solution state. This is never observed in previous studies of SMMs, indicating that the adamantanol ligand is rigid enough to make the complexes exhibiting intrinsic magnetic property in solution. As vibration spectrometer is routinely accessible in common laboratories this work provides a facile strategy to construct high-performance SMMs.

Cu 1– x Fe x O: hopping transport and ferromagnetism

Single phase, sol–gel prepared Cu 1 –x Fe x O (0 ≤ x ≤ 0.125) powders are characterized in terms of structural, electronic and magnetic properties. Using dielectric and magnetic studies we investigate the coupling of electron and spin. The electrical conductivities and activation energies are studied with increasing Fe content. Modelling of experimental conductivity data emphasizes a single hopping mechanism for all samples except x = 0.125, which have two activation energies. Hole doping is confirmed by confirming a majority Fe 3+ substitution of Cu 2+ in CuO from X-ray photoelectron spectroscopy studies (XPS). Such a substitution results in stabilized ferromagnetism. Fe substitution introduces variation in coercivity as an intrinsic magnetic property in Fe-doped CuO, and not as a secondary impurity phase.