No abstract

The characteristics of organic molecular/ferromagnet spinterfaces are highlighted, including hybrid interface states, magnetic anisotropy, magnetic exchange interaction, etc.

SnS hollow nanoparticles (HNPs) were fabricated by a two-step method, where laser ablation of a Sn target was first conducted in ethanol solution of thioacetamide to synthesize Sn@SnS core-shell nanoparticles, and then acid etching was employed to eliminate the Sn cores. The as-obtained SnS HNPs are uniform and nearly spherical with a size of y40 nm. Moreover, the shell thickness of the HNPs can be facilely modified by adjusting the concentration of thioacetamide in the first step.

Fully epitaxial Fe3O4/BiFeO3 bilayers were deposited on (001) LaAlO3 and SrTiO3 by magnetron sputtering. BiFeO3 remained tetragonal on highly misfit-strain LaAlO3 substrates. Obvious exchange bias with a reciprocal relation to the thickness of ferromagnetic Fe3O4 was observed in the Fe3O4/tetragonal-like BiFeO3 (Fe3O4/T -BiFeO3) bilayers below ∼ 100 K which is similar to that of Fe3O4/rhombohedral-like BiFeO3 (Fe3O4/R-BiFeO3) bilayers. An unexpected enhancement of exchange bias from ∼ 160 Oe in Fe3O4/R-BiFeO3 to ∼ 320 Oe in the Fe3O4/T -BiFeO3 bilayer was observed at 3 K, which could be attributed to the enhanced Fe-O-Fe interfacial superexchange (SE) interaction induced by distorted T -BiFeO3.

Organic magnetic tunnel junctions (OMTJs) are promising systems thanks to their chemically tunable electronic property, long spin lifetime, and easy functionalizations. Here, the spin-dependent electronic transport properties in Fe3O4/4,4′-bipyridine/Fe3O4 OMTJs are investigated by first-principles quantum transport calculations. Since the transport properties of junctions are sensitive to device details, two types of terminations of Fe3O4 electrodes are considered. The device with tetrahedral Fe termination shows anomalous negative tunnel magnetoresistance (TMR), that is, which has a higher and lower junction resistance in the parallel and antiparallel magnetization configurations, respectively. When the contact termination is octahedral Fe, a large positive TMR of 180% appears. The difference in TMR sign of two OMTJs originates from the electrons transmission mediated by frontier molecular levels coupled differently to Fe d states. Furthermore, TMR can be effectively controlled by applied electrical bias by changing states of octahedral Fe involved in transport, which can reach 22000% at 0.1 V. Moreover, a perfect spin-filter effect is demonstrated irrespective of the contact geometry. The results contribute to a fundamental understanding of spin-dependent transport properties in OMTJs.