Status of the Bio-Nano electron cyclotron resonance ion source at Toyo University

In the paper, the material science experiments, carried out recently using the Bio-Nano electron cyclotron resonance ion source (ECRIS) at Toyo University, are reported. We have investigated several methods to synthesize endohedral C60 using ion-ion and ion-molecule collision reaction in the ECRIS. Because of the simplicity of the configuration, we can install a large choice of additional equipment in the ECRIS. The Bio-Nano ECRIS is suitable not only to test the materials production but also to test technical developments to improve or understand the performance of an ECRIS.

Synthesis of endohedral iron-fullerenes by ion implantation

In this paper, we discuss the results of our study of the synthesis of endohedral iron-fullerenes. A low energy Fe+ ion beam was irradiated to C60 thin film by using a deceleration system. Fe+-irradiated C60 thin film was analyzed by high performance liquid chromatography and laser desorption/ionization time-of-flight mass spectrometry. We investigated the performance of the deceleration system for using a Fe+ beam with low energy. In addition, we attempted to isolate the synthesized material from a Fe+-irradiated C60 thin film by high performance liquid chromatography.

Spin and charge orders and their hole-doping dependence in single layered cobaltate La2-xCaxCoO4(0.3<x<0.8)

Neutron scattering experiments were performed on single crystals of layered cobalt-oxides La2-xCaxCoO4 (LCCO) to characterize the charge and spin orders in a wide hole-doping range of 0.3<x<0.8. For a commensurate value of x=0.5 in (H,0,L) plane, two types of superlattice reflections concomitantly appear at low temperature; one corresponds to a checkerboard charge ordered pattern of Co2+/Co3+ ions and the other is magnetic in origin. Further, the latter magnetic-superlattice peaks show two types of symmetry in the reflections, suggesting antiferromagnetic-stacking (AF-S) and ferromagnetic-stacking (F-S) patterns of spins along the c direction. From the hole-doping dependence, the in-plane correlation lengths of both charge and spin orders are found to give a maximum at x=0.5. These features are the same with those of x=0.5 in La1-xSr1+xMnO4 (LSMO), a typical checkerboard and spin ordered compound. However, in (H,H,L) plane, we found a magnetic scattering peak at Q=(1/4,1/4,1/2) position below TN. This magnetic peak can not be understood by considering the Co2+ spin configuration, suggesting that this peak is originated from Co3+ spin order. By analyzing these superlattice reflections, we found that they are originated from high-spin state of Co3+ spin order.