Masaaki Matsui

Preoperative thermochemotherapy of oral cancer using magnetic induction hyperthermia (Implant Heating System : IHS)

Eight patients with primary cancer of the oral cavity were preoperatively treated by combined treatment with hyperthermia and chemotherapy. They received two courses of chemotherapy, which included intra-arterial infusion of 100 mg of cisplatin (CDDP) and 25 mg of peplomycin (PEP) via the superficial temporal artery. The patients also received interstitial hyperthermia for 45 min once a week using the Implant Heating System (IHS) with chemotherapy. IHS consists of ferromagnetic implant, induction coil and generator to produce high frequency magnetic field. The ferromagnetic implant is made of Fe-Pt alloy (Fe: 73%, Pt: 27%), and has a Curie temperature of 68 degrees C. As a result, clinical complete response (CR) was observed in seven patients and partial response (PR) in one, and postoperative pathological examination showed no residual tumour cells in any specimen. Combined interstitial hyperthermia by IHS and chemotherapy is thus found to be an effective therapeutic method for treating oral cancers.

Atomic Rearrangement and Magnetism of [Fe/Cu] Multilayers on Cu(001)

Multilayers of [7ML Fe/14ML Cu] on Cu(001) were prepared. A rearrangement of Fe atoms is observed, when Fe is deposited on a flat Cu-buffer surface. The degree of rearrangement depends on the flatness of the buffer surface. The structure of the rearrangement is 3D-( n ×1), n = 2, 3, 4, 5 etc. and the mean magnetic moment of the Fe atoms in a sample which contains many rearranged atoms is about 0.7 µ B , while that of a sample mainly with fcc structure is 1.6 µ B . The various values of Fe moments for multilayers with the same design are corresponding to the mixture of the 3D-( n ×1) and fcc structures in the film. The fcc structure of Fe is obtained when Fe is deposited on a rough Cu-buffer surface.

Epitaxial growth of Ni, Cu on bcc-Fe(001) and Ni on fcc-Au(001)

We have studied structural change of MBE grown Ni/Fe(001) and Cu/Fe(001) thin films using RHEED and X-ray diffraction measurements. Epitaxial bct-Ni film is grown initially up to 3 ML, then it changes to reconstructed c(2×2)-like structure for thicker film. 200 ML thick Ni film annealed at 520 K shows the clear formation of twinned domains of fcc-Ni{110}. The structural change of Cu films exhibits almost the same as Ni, except that it maintains bcc symmetry up to about 9 ML. Considering the lattice mismatch and the atomic volume, we discuss these differences of structural change between Ni and Cu. Epitaxial growth of Ni on fcc-Au(001) is also reported.

Solid-state amorphization in palladium/titanium multilayer films during sputter deposition and postdeposition annealing

Microstructures in Pd/Ti multilayer films have been investigated using X-ray diffraction, Auger electron spectroscopy and cross-sectional transmission electron microscopy. Multilayer films consisting of crystallites with preferred orientations in Pd and Ti layers after deposition exhibit crystalline-to-amorphous phase transition during thermal annealing at 573–623 K. This solid-state amorphization reaction is discussed in terms of a metastable phase diagram calculated for this system.

Structure and magnetic properties of metastable Ni/bcc-Fe multilayers

Ni/bcc-Fe(001) multilayers have been grown by means of MBE. RHEED and X-ray diffraction patterns indicate that the structure of 3ML Ni on bcc-Fe(001) is “bct”, instead of an expected bcc structure. The magnetic moment of bct-Ni is evaluated as 0.8 µ B at 4.5 K, where we assume that the moment of Fe is equivalent to that of bulk Fe. The band calculation of the multilayer indicates that the observed enhancement is due to the enhanced moments of Ni and Fe at the interface.

Microstructure of Fe/Cu (Au) artificial superlattice

Microstructures of artificial superlattices of fcc-Fe/Cu (Au) having different magnetic properties have been studied by means of cross-sectional transmission electron microscopy (TEM). The superlattice made on a very flat substrate whose saturation magnetization was about 25 emu/g Fe constituted a flat film with the step of < 1 nm at the interface between Fe and Cu (Au). On the other hand, the film on a slightly rough substrate having a larger magnetization showed a wavy contrast with a width of several hundred nanometers and a height of several tens of nanometers reflecting the geometry of the substrate. At the interfaces a wavy contrast with a width of several tens of nanometers and a height of several nanometers was observed. The difference of the microstructures in these two samples was mainly this wavy geometry at the interface inside the superlattice. The observed microstructure must play an important role influencing the magnetic property of the superlattice.

Scanning Tunneling Microscopy in Liquid on Geometrical Study of Cu(001) Surface

Scanning tunneling microscopy (STM) in liquid was applied in order to prevent the influence of oxidation in air. Using 1,2,4-trichlorobenzene as a liquid for our STM studies, an image of a Cu (001) surface was taken with high reproducibility and an atom image was also obtained. The surface geometry of Cu (001) differently polished from bulk crystals was investigated.

Preparation of a Nd-Fe-B Bond Magnet using High Frequency Magnetic Fields

In this study we suggest a new method to prepare an anisotropic bond magnet. In order to achieve an anisotropic magnet we take advantage of the magnetic anisotropy of the tetragonal Nd2Fe14B crystals. A dispersion of a melt spun Nd–Fe–B magnet powder with epoxy resin was hardened in a high frequency (HF) magnetic field (ν= 230 kHz) to align the easy magnetization axis (c-axis in Nd2Fe14B) with the external field. Magnetization measurements and an X-ray analysis showed that an alignment of the powder due to the treatment in a HF magnetic field was achieved. A Mosbauer analysis confirmed the alignment.

Substitution Effects of 3d Transition Metal Elements, Zn and Li to Cu- site of Bi-oxide Superconductors

We have prepared Bi-oxide superconductors Bi2Sr2Ca(Cu1−xxMx)2Oy (x=0.0˜0.15, M=Ti, V, Cr, Mn, Fe, Co, Ni, Zn and Li). X-ray diffraction and EDX analysis revealed that 2212 structure was preserved for x=0.0˜0.15. Critical temperature Tc was plotted as a function of the ionic radius of substitution atoms. Decreasing of Tc(on) with respect to x, dTc/dx, is large in cases of Fe and Co and small in cases of Zn, Ni, Mn, Cr, V, and Ti. Li doping enhanced Tc. We conclude that substitution of Fe and Co supresses the superconducting properties through a magnetic interaction with Cu spins in Cu-O2 planes.

MD Simulation of Thin Film Using N-Body Embedded Potential

Molecular dynamics simulation has been performed for the thin film growth of Cu metal on fcc Cu (001) and (111) planes at substrate temperatures, 300, 500 and 700K, using an N-body embedded potential for the 12×12 atoms in dimension of the base of substrate. The S-K mode is predicted for the thin film growth of pure Cu at 700K for (001) and over 700K for (111) systems.