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Effects of polyamines on the development of embryonal-suspensor masses (ESMs) and the formation of somatic embryos were examined in an effort to improve the frequency of somatic embryogenesis in Picea glehnii. Exogenous spermidine at 100 and 300 μM promoted the elongation of suspensors and the formation of somatic embryos. Exogenous putrescine at 100 μM increased the number of somatic embryos and decreased the time required for formation of somatic embryos. Thus, exogenous polyamines improved the maturation capacity of ESMs and promoted the formation of somatic embryos in P. glehnii. Light microscopy revealed that ESMs with high maturation capacity consisted of the three following cells: round or oval cells, elongated cells, and protean cells. These components might be related to the capacity for formation of somatic embryos.

The increasing atmospheric concentration of carbon dioxide (CO2) has been driving all marine organisms to live in increasingly acidic environments. In the present study, we evaluated the long-term effects of increased seawater CO2 on survival, growth, feeding and moulting of the marine shrimp Palaemon pacificus. The shrimps were reared in seawater equilibrated with air containing 1,000 ppmv (parts per million by volume, seawater pH 7.89 ± 0.05) or 1,900 ppmv (pH 7.64 ± 0.09) CO2, the atmospheric CO2 concentrations predicted for the year 2100 and 2300, for 30 and 15 weeks, respectively. Survival was significantly suppressed in both experimental groups compared to respective controls; final survival rates were 55% (experimental) vs. 90% (control) in the 1,000 ppmv experiment, and 65% (experimental) vs. 95% (control) in the 1,900 ppmv experiment. Growth was unaffected in the 1,000 ppmv experiment but significantly depressed compared to the control after 7 weeks in the 1,900 ppmv experiment. Feeding was unaffected by either treatment. Moulting frequency was significantly affected in both 1,000 ppmv (experimental > control) and 1,900 ppmv (experimental < control) experiments. Egg production was suppressed in the 1,000 ppmv shrimps compared with the control (no observation was made in the 1,900 ppmv experiment). In addition, the second antennae determined at the end of the experiment were significantly shorter in the 1,000 ppmv shrimps than in the control. The present results demonstrate for the first time that the predicted future seawater CO2 conditions would potentially reduce shrimp, and possibly other crustacean, populations through negatively affecting mortality, growth, and reproduction. This could threaten entire marine ecosystem through disrupting marine food web., Journal of Experimental Marine Biology and Ecology, 367(1), pp.41-46; 2008

We have investigated the preparation, structures, and magnetic properties of bulk Fe2CrSi and Fe2Cr1-xTixSi Heusler alloys. Although a Cr-rich secondary phase coexists with the Heusler mother phase in stoichiometric Fe2CrSi samples, high temperature annealing (1200°C) effectively reduces the extent of the Cr-rich secondary phase. We found that pure single-phase samples can be prepared in a narrow composition range of 22% Cr. For a Fe2Cr1-xTixSi system with Ti content x of up to 1/8, virtually single-phase Heusler alloys have been obtained. The saturation magnetization of Fe2Cr1-xTixSi decreased with increasing Ti content, while their Curie temperatures Tc remained constant.

GMR multilayer films using Co2MnGe(CMG) and Mn-Ir/CMG exchange-coupled films were fabricated on thermally oxidized Si substrate, and their crystal orientation, magnetic properties, and interfacial roughness were investigated. The main results are stated as follows. (1) (100) oriented MnIr/CMG exchange-coupled films were realized when Ni-Ta underlayer/Cr buffer layer were deposited on thermally oxidized Si substrate. After thermal annealing for 2h at 250°C in a magnetic field of 5 kOe, the unidirectional anisotropy constant (JK) of bilayers was 0.13 erg/cm2. (2) Dependence of saturation field (Hs) on Cr thickness for GMR films with (100) oriented CMG/Cr/CMG trilayer was investigated. Hs was minimum when Cr thickness was 1 nm and 5 nm. (3) Surface roughness (Ra) of Ni-Ta 5 nm on Al-Cr bottom electrode layer(100 nm) was 0.108 nm. (4) Flat and (100) oriented CMG/Cr films was formed on Al-Cr bottom electrode layer (100 nm)/Ni-Ta underlayer (15 nm)/Cr buffer layer (60 nm) when Cr content of the Al-Cr layer was 18.7-24.6 at%.

Thin films of ordered double perovskite Sr2CrReO6 were sputter-deposited on SrTiO3 (001), (111), LaAlO3 (001) substrates. With high quality thin films of the double perovskite Sr2CrReO6, we have investigated the electronic state of the inside of the Sr2CrReO6 thin films by Synchrotron Radiation photoelectron spectroscopy (XPS). The Re 4f spectrum of Sr2CrReO6 has shown a multiple peak structure, which originates from the electronic state of Re in half-metallic Sr2CrReO6. Moreover, it has been found that the electronic densities of states clearly exist on the Fermi energy.

Thin films of ordered double perovskite Sr2FeMoO6 were sputter-deposited on Ba0.4Sr0.6TiO3-buffered SrTiO3 substrates, and their surface properties were examined by atomic force microscopy (AFM) and X-ray photoemission spectroscopy (XPS). The Mo 3d spectra of Sr2FeMoO6 films showed a multiple peak structure, which originated from the unusual electronic state of metallic Sr2FeMoO6. Systematic XPS studies of the air-exposed surface of Sr2FeMoO6 film indicated that the surface native barrier was an insulating SrMoO4. In addition, a TMR junction with the native barrier was fabricated using a convention photolithographic technique, and an MR ratio of 10 % was observed at 4.2 K.

High quality Fe3O4 thin film was synthesized by the magnetron sputtering method using Ar-H2 gas. Giant magneto resistance of the trilayer using Fe3O4 was investigated, where the observed MR ratio was less than 1%. A phenomenological calculation was made to make the origin of the small MR ratio clear, using a parallel current model assuming five passes. It is concluded that the non-magnetic layer surrounded by two magnetic layers is necessary to have the same order resistivity and similar thickness with Fe3O4 layer in order to obtain the large MR ratio for the trilayer using Fe3O4.

Ferromagnetic oxides with ordered double-perovskites Sr2FeMoO6 and Sr2CrReO6 are known to be in a half-metallic ground state with high Curie temperatures Tc, and hence one of the promising materials for spin electronics. This paper reports epitaxial growth and micro-structural, magnetic, and electrical characterization of thin films of these oxides. It is shown that a coherent growth without strain relaxation, which is accomplished by the use of substrate or buffer layers with a small (0.1%) lattice match, is essential to obtain high quality films with both atomically flat surface and high magnetization values expected for their half-metallicity

We report studies on Andreev reflection measurements of ferromagnetic materials at junction interfaces using AlN/NbN junctions. We found that the junction resistance R can be controlled by varying the thickness and growth temperature of an AlN interlayer. The spin polarization of Co was determined to be PCo ≈ 0.44 from theoretical fitting of the conductance data for these junctions. The behavior of PCo and the dimensionless barrier parameter Z depending on the junction resistance R is discussed.

The structural and magnetic properties of Co2MnSi thin film grown by the ion beam sputtering method were investigated. Films grown on glass substrate at temperatures from 300°C to 600°C were polycrystalline, as were films grown on Si(100) and MgO(100) substrates at 600°C. The crystalline quality of the film improved with increasing substrate temperature. Film grown at 600°C showed the largest magnetization near the bulk value. On the other hand, film with the preferred orientation to the (001) plane was obtained by growing a Ta buffer layer before the growth of Co2MnSi film on any substrates. The saturation magnetization increased with the increase of substrate temperature. This fact is considered to be due to the increase of the long-range order parameter.

Insulator layers of Nd2CuO4 (NCO) and Ba0.4Sr0.6TiO3 (BSTO), which have a good lattice matching to SFMO, were epitaxialy grown on SFMO by magnetron sputering in different preparation atmospheres (Ar, Ar+H2, Ar+O2). The quality of SFMO was evaluated by measurement of magnetization and crystal structure. We suggest that insulator materials having a small misfit to SFMO and the same preparation condition (Ar+H2) as SFMO are suitable as insulators of TMR junctions. We also demonstrated the hetero-epitaxial growth of SFMO/NCO/SFMO trilayers.

Magnetic properties and heat generation characteristics of a bio-compatible ceramic Mg1+xFe2−2xTixO4 system have been investigated as an implant material for the magnetic induction hyperthermia. Curie temperature (Tc) of the ceramic decreases with increasing x, and become Tc~350 K at x=0.35 and ~315 K at x=0.38, which is suitable Curie temperature for implant material. The temperature of ceramic as a function of time under the high frequency alternating magnetic field is self-controlled at Tc.The surface temperature of a powder injection sphere cancer model, which was a mixture of the agar phantom and the ceramic powder implant, and the temperature distribution around the sphere set in the pure agar phantom matrix have been measured. The result is in good agreement with calculation using a finite element method (FEM). It was found that the temperature distribution inside of the sphere and the minimum quantity of Mg1+xFe2−2xTixO4 necessary for hyperthermia could be estimated by the FEM calculation.

Surface active agent (surfactant) effect of the adsorbed oxygen atoms on epitaxial growth of fcc ultra thin films (Co, γ-Fe, Cr) on Cu(001), a Co/γ-Fe/Co trilayer on Cu(001) and a [Co/Cu] multilayer was investigated. The surfactant effect of oxygen atoms on the growth of fcc Co on Cu(001)-O reconstructed structure of (2√2 × √2) R45° was found by the RHEED observation. The non-equilibrium fcc structure of Fe was stable until 45 ML on the Cu(001)-O surface formed on Cu(001) single crystal, but 20 ML on the Cu(001)-O surface formed on Cu(001) buffer layer deposited on MgO(001). The surfactant effect was not observed for the non-equilibrium fcc Cr. The surfactant effect of oxygen atoms on the Co/γ-Fe/Co trilayer and [Co/Cu] 20 multilayer were observed. The surface reconstruction structure of Cu(001)-O(2√2 x √2)R45° is necessary for the oxygen surfactant effect on the epitaxial growths of fcc metals on Cu(001).

Growth mode of epitaxial ultrathin γ-Fe film on the Cu(0 0 1) substrate with O 2 2 × 2 R45° reconstruction surface has been investigated via reflection high energy electron diffraction (RHEED) observation. The γ-Fe structure and surface O 2 × 2 R45° reconstruction were kept till 45 monoatomic layers (ML) with the streak pattern as proof of non-island growth mode. All oxygen atoms adsorbed on Cu(0 0 1) are floated onto 45 ML γ-Fe surface considering from the RHEED patterns. The oxygen in the state of Cu(0 0 1)–O 2 2 × 2 R45° reconstruction surface exhibited a strong surfactant function for the γ-Fe growth on the Cu(0 0 1) with stabilizing effect on the film. We succeeded to prepare relatively thick and pure γ-Fe film on Cu(0 0 1) by this method. Magnetization of a series of γ-Fe films was measured as a function of Fe thickness. A part of γ-Fe layer shows non-magnetism in the low spin state.

Spin polarization and electronic structure of Co90Fe10 were investigated through tunneling magnetoresistance (TMR) effect measurements on the Mn80Ir20/Ni80Fe20/Co90Fe10/SrTiO3/La0.7Sr0.3MnO3 junction. This junction was fabricated with half-metallic ferromagneto-LSMO and has a spin-valve type structure. An inverse TMR of 14 % was observed at 4.2 K. As the spin polarization of the LSMO is positive, the inverse TMR observed in this junction indicates a negative polarization for Co90Fe10 at the interface. The bias dependence of TMR is asymmetric to the applied bias. The band structure calculated with the LMTO-CPA method showed that spin polarization for Co90Fe10 is negative at the Fermi level.

Epitaxial growth mode and morphology of Fe on Cu(111), affected by the pre-adsorbed oxygen in the form of a “29” structure of the Cu(111) surface, were investigated by scanning tunneling microscopy (STM) and reflection high-energy electron diffraction (RHEED). According to RHEED observation, the γ-Fe structure was kept to more than 3 monoatomic layers (ML) and fcc and bcc structures coexisted at 5 ML . In contrast, the RHEED pattern of 1 ML Fe on a clean surface already shows the coexistence of fcc and bcc structures. By STM observation, at about 0.4 ML of Fe on the oxygen absorbed Cu(111) surface, small islands appeared on the surface with a high density instead of decorating the step edges with large islands about 6 ML high for the iron growth on a clean Cu(111) surface. As the surface diffusion was suppressed due to oxygen adsorption, the growth mode was significantly changed. However, no strong surfactant effect was observed as in Fe growth on oxygen-adsorbed Cu(001) surface where the γ-Fe structure was kept to 45 ML with a surface O (\\sqrt2×\\sqrt2)R45° reconstruction and all the oxygen floated to the surface.

The magnetic phase transition of [m ML Fe/12.5 ML Au] 20 (m=0.7, 0.9, 1.1) multilayers was investigated. The quality of samples was well defined by RHEED observation and the 4 circle X-ray diffraction method. Perpendicular anisotropy was observed for samples thinner than 2ML Fe. The Curie temperature TC and a critical exponent β were precisely determined by the new method to evaluate the spontaneous magnetization from the measured magnetization as a function of temperature. The Curie temperature TC decreased with decreasing Fe thickness. The critical exponent β for an ultra-thin Fe layer of around 1 ML is similar to that for the Heisenberg model. The spacer layer of Au plays an important role in making the system's three-dimensional ferromagnetism.

La0.7Ca0.3MnO3 (LCMO) films grown on (0 0 1) surfaces of various (pseudo-) cubic substrates, MgO, SrTiO3, LaSrGaO4 and YAlO3, were studied by means of transmission electron microscopy. In all cases, the (0 0 1) plane of LCMO perovskite primitive cell is parallel to the substrate surface. The film on SrTiO3 showed the single-variant structure with many twin boundaries while the films on other substrates had the three-variant structure where three [0 1 0] axes of the orthorhombic unit cell are perpendicular to each other. The LCMO cell on SrTiO3 was expanded by about 1% in the film plane and shrank by about 1% out of the plane. Many planar defects and intergrown grains were observed in the film on MgO. They originated at the substrate surface.

In magnetic metallic multilayers and thin films the roughness at the interface of the non-magnetic and the magnetic layers is an important factor to determine their magnetic properties. In this work we present a combined study of reflection high-energy electron diffraction (RHEED) and scanning tunneling microscope (STM) observations of epitaxially grown Fe/Cu(001) multilayers. For a Fe layer thickness of about six monolayers in a 20-period multilayer a strong dependence of the magnetization on the surface roughness was found. A rough surface leads to a higher saturation magnetization.

The interface structure of Fe(Co)/AlOx/Fe ferromagnetic tunnel junctions (MTJ) was studied. Junctions were prepared by the metal mask method on glass, MgO(001), and sapphire (1120) substrates, using molecular beam epitaxy (MBE) and ion beam sputtering (IBS). The surface of a lower-electrode Fe layer grown on single-crystal MgO and sapphire by MBE was rougher than that deposited on a glass substrate by IBS. Al oxide barrier layers were prepared by natural oxidation of Al metal or direct deposition of Al2O3. AFM observation showed that the flattest surface of Al oxide was obtained by the direct deposition of Al2O3. CEMS measurement revealed that 65% of Fe atoms at interfaces between Fe and AlOX were oxidized or alloyed when the Al layer was oxidized at 50°C for 48 hours in air. On the other hand, in the case of Fe(Co)/Al metal/Fe and Fe(Co)/Al2O3/Fe, only two ferromagnetic components, pure Fe and Fe(Co), were observed, suggesting the existence of pin holes in the Al or Al2O3 layer.

The electrical and magnetic properties, including the magnetoresistance (MR) effect, of Lan-nxCa1+nxMnnO3n+1 thin films (n = ∞, 2; x = 0.3) grown on various substrates were investigated. For n = 2 (La1.4Ca1.6Mn2O7) thin films, the cusp temperature (Tcρ) in the ρ-T curve decreased very sharply with a decrease of the out-of-plane lattice parameter (a). The MR effect was enhanced drastically by decreasing Tcρ. These behaviors are interpreted in relation to the change in the transport character along the c-axis due to the strain.

The thermo-magnetization curve, magnetic susceptibility at high temperatures, and X-ray diffraction measurement for water-quenched and slow-cooled Mg1+xFe2−2xTixO4 samples were measured. The magnetic exchange interaction JAB between A- and B-sites in the inverse spinel structure and Curie temperature were evaluated, using Rietveld analysis and fitting the susceptibility to molecular field theory. The Curie temperature estimated was in good agreement with experimental data, except for a slight upper deviation of calculated Tc. The deviation might come from the correlation between JAB and angle ϕ of Fe–O–Fe ions.

Low-temperature structural transformation of (Ni1−xCox)2MnGa was investigated experimentally and theoretically. Magnetization measurement as a function of temperature in the low magnetic field revealed that the transformation temperature T1 disappeared for x ⩾ 0.2 . The band calculation predicted that the stabilization of austenite L21 phase occurred for x > 0.3 , which was in rough agreement with the experimental result. Furthermore, the instability of austenite phase was discussed from the viewpoint of Hume–Rothery regime and the prediction was in good agreement with the results. It was concluded that the Galanakis curve was a good prediction for half-metal Heusler alloy and a new Heusler alloy was proposed for 1.0 > x ⩾ 0.7 .

Control of (1 0 0) crystallographic orientation of Heusler-alloy film using buffer layer and seedlayer onto a thermally oxidized Si wafer has been investigated, in order to realize low surface roughness and highly L2 1 ordered structure of the Heusler-alloy film, which is important to obtain high TMR ratio on magnetic tunnel junction (MTJ). The main results are as follows: (1) Cr buffer layer shows strong (1 0 0) orientation on Ta or Ni–Ta seedlayer with a certain amount of oxygen exposure onto the seedlayer surface, whereas Cr buffer layer shows polycrystalline structure on a thermally oxidized Si wafer directly. (2) Co 2 MnGe layer shows (1 0 0) orientation on the (1 0 0) oriented Cr buffer layer. (3) Surface roughness of Cr buffer layer and Co 2 MnGe layer are 0.27 and 0.34 nm, respectively. (4) Saturation magnetization of (1 0 0) oriented Co 2 MnGe layer fabricated on a thermally oxidized Si wafer is 93 emu/g, which is almost same value as the case of (1 0 0) epitaxial Co 2 MnGe layer fabricated on MgO(1 0 0) substrate. It is found that Heusler-alloy film with (1 0 0) orientation onto a thermally oxidized Si wafer was useful to realize high performance of MTJ.

This paper reports X-ray photoelectron spectroscopy (XPS) study on thin films of half-metallic materials with an ordered double-perovskite structure. The XPS core-level spectra were measured for several Sr 2 FeMoO 6 (SFMO) and Sr 2 CrReO 6 (SCRO) films with and without in situ deposited thin overlayers of MgO and SrTiO 3 . For a fresh SFMO film surface, the XPS spectrum of the Mo 3d region showed a multiple feature, which reflects the ferrimagnetic metallic nature. Whereas SFMO films with overlayers of SrTiO 3 showed degraded interface properties, films with overlayers of MgO showed the multiple feature similar to the fresh SFMO surface, indicating that the electronic properties at the MgO interface were preserved. Very similar tendency was observed for the Re 4f core-level spectra of the SCRO/overlayer systems.

[fcc-Fe/Cu] multilayers on Cu(001) were investigated by fluorescence EXAFS (extended X-ray absorption fine structure) in order to study relationship between local structures around the Fe atoms and their magnetic properties. The EXAFS analysis revealed that the Fe–Fe bond length of fcc-Fe becomes longer with the increase of the surface roughness of the Cu substrate, thus resulting in increase of the magnetic moment per Fe atom in fcc-Fe. The magnetic moments per Fe atom which were estimated from the volume ratio obtained by EXAFS results agreed with those measured by VSM.

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.

The resistivity and magnetization of layered perovskite La{sub 2{minus}2x}Ca{sub 1+2x}Mn{sub 2}O{sub 7} have been studied systematically using bulk samples with a wide doping concentration range 0{le}x{le}0.5 and epitaxial thin film samples with x=0.3. The system becomes a metallic ferromagnet for doping concentrations 0.22{le}x{le}0.5. In this doping region, results for bulk samples as well as for thin films have clearly shown that there are two types of ferromagnetic ordering, possibly originating from an anisotropic exchange interaction. Magnetoresistance is observed over a wide temperature range below the ferromagnetic ordering temperatures. Based on these results, a model of temperature-dependent spin ordering is presented for a double perovskite ferromagnet, which suggests that there is a two-dimensional ferromagnetic alignment at temperatures between the two ordering temperatures. {copyright} {ital 1997} {ital The American Physical Society}

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.

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.

This paper reports the magnetic, electrical, and microstructural properties of epitaxial thin films with an ordered double-perovskite structure. Sr/sub 2/ FeMoO/sub 6/ (SFMO) and Sr/sub 2/ CrReO/sub 6/ (SCRO) films have been grown by sputtering onto the lattice-matched substrates of Ba/sub 0.4/ Sr/sub 0.6/ TiO/sub 3/ -buffered and bare SrTiO/sub 3/, respectively. These films exhibit high saturation magnetization M/sub s/ values (3.8 /spl mu//sub B//f.u. for SFMO and 0.9 /spl mu//sub B//f.u. for SCRO), which are close to the expected values for their half-metallicity, and high curie temperature T/sub c/ values (385 K for SFMO and 620 K for SCRO). Surface analyzes by AFM and XPS indicate that these films have atomically flat and well-defined surfaces, which are free from any surface precipitates. This enables us to employ a standard photolithographic process for fabricating magnetic tunnel junctions based on these films. SFMO junctions with a native barrier formed by surface oxidation of a SFMO base-electrode and a Co counterelectrode have shown a tunnel magnetoresistance ratio of 10% at 4.2 K.

Magnetization and susceptibility of (CuIn) 1- x Mn 2 x Te 2 were calculated using the extended nearest neighbor pair approximation. A good fit of the experimental data including the occupation of tetrahedral interstitial sites was achieved for the sample with x =0.048 yielding a nearest neighbor Mn-Mn exchange integral of -24 K at a nearest neighbor distance of half the lattice constant a in the chalcopyrite structure.

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.

In this study we report about the magnetic properties of (CuIn) 1- x Mn 2 x Te 2 . The magnetization measurements on samples with Mn concentrations up to x =0.5 showed a similar behavior as other diluted magnetic semiconductors. An analysis of the spin glass freezing temperatures suggests a farther reaching and stronger interaction between the Mn ions than in the corresponding II-VI compounds Zn 1- x Mn x Te and Cd 1- x Mn x Te.

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.

Thin films of ordered double-perovskite Sr_2CrReO_6 have been grown epitaxially onto SrTiO_3 substrates by sputtering, and their microstructural, electrical, and magnetic properties are investigated. It is found that a wide growth-temperature range of at least 700–800 ℃ can yield epitaxial films with superior magnetic properties and atomically flat surfaces. These films exhibit Curie temperatures Tc of up to 620 K, and saturation magnetizations Ms of 0.9μ_B/formula unit (f.u.), which is comparable to the predicted value of 1μ_B/ f.u. for the fully ordered half-metallic material. Owing to the wide temperature window for growth of high-quality films, the surface morphology and coercivity of Sr_2CrReO_6 films are highly controllable, which is favorable for fabrication of magnetic tunnel junctions.

GMR effect of [Co–Fe/Cu] and [Co/Cu] multilayers has been investigated. The samples have been prepared by an ion beam sputtering method, an UHV-MBE or an oxygen surfactant assisted MBE (OSA-MBE) method. The MR ratios for samples of [Co–Fe/Cu](1 1 1), [Co–Fe/Cu](1 0 0) [Co/Cu](1 1 1) and [Co/Cu](1 0 0) are measured as a function of Cu layer thickness. Especially, it is first revealed that the MR ratio for [Co–Fe/Cu](1 0 0) is much larger than that for [Co–Fe/Cu](1 1 1). The very small MR ratio for [Co/Cu](1 0 0) is discussed.

The magnetoresistance of [Co/M/Fe 3 O 4 ](M=Pt, Cu, TiN) trilayer films has been investigated. The high-quality Fe 3 O 4 film prepared by the magnetron spattering method using Ar–H 2 gas has been used. The GMR effect has been observed only for [Co/Cu/Fe 3 O 4 ]. The GMR values are 0.1% and 0.7% at RT and 4.2 K, respectively. The magnetoresistance effect for trilayers using Fe 3 O 4 film is discussed, considering the current ratio among three layers.

The paramagnetic resonance of Mn2+ in the diluted magnetic semiconductor (CuIn)1−xMn2xTe2 was observed in a pulsed magnetic field up to 15 T at temperatures ranging from 4.2 K to 45 K. The temperature dependence of the line width of the paramagnetic resonance in (CuIn)1−xMn2xTe2 resembles the behaviour of other diluted magnetic semiconductors. A Dzyaloshinski-Moriya exchange constant of approximately 0.62 K was derived. This value fits well with the values reported for II–VI based diluted magnetic semiconductors [1], if we consider the larger degree hybridization of the 3d electrons with the band electrons in chalcopyrite semiconductors.

The current-perpendicular-to-plane giant magnetoresistive (CPP-GMR) devices having half-metallic Fe3O4 for their magnetic layers were investigated along with the fabrication of Fe3O4 films on Au layers at low temperature (523 K). The 10–50-nm-thick Fe3O4 films that were grown on a 100 nm Au (111) layer were Fe3O4 (111) oriented. These films showed Verwey transition at ∼120 K. Using these films, the relation between the magnetoresistive (MR) effect of CPP-GMR and the Fe3O4 layer thickness was examined with 2×2 μm2 samples of Ni80Fe20/Au/Fe3O4 trilayers on Au bottom electrode films. At the Fe3O4 layer thickness of 20 nm, the MR ratio was 0.04% and the area magnetoresistance-change product (ΔRA) was 1.5 mΩ μm2. The MR ratio was increased with decrease in the Fe3O4 thickness. The CPP-GMR of Fe3O4/Au/Fe3O4 on the Au layer showed that the MR ratio was 0.04% and the ΔRA was 3.9 mΩ μm2. This MR ratio was four times larger than that of the NiFe-type CPP-GMR for the same Fe3O4 bottom layer thickness.

In order to determine the value of the intrinsic magnetic moment of the α ‘ phase, the films of nitrogen‐martensite with various N content were fabricated under various reactive sputtering conditions. The magnetic moment of (α ‘+α’)‐Fe16N2 films is discussed in connection with the change of the unit‐cell volume of the bct structure and the degree of N site ordering in nitrogen‐martensite. As a result, it is found that (1) the same structure as bulk α ‘‐Fe16N2 is realized in the present films, (2) the saturation magnetization σs of the α’ phase increases about 4% with increasing unit‐cell volume of the α’ phase, (3) the degree of N site ordering from α’ to α ‘‐Fe16N2 does not much affect σs, and (4) the experimentally obtained maximum value of σs for the (α ‘+α’)‐Fe16N2 film was 232 emu/g. The intrinsic value of σs in the α ‘ phase (in the perfectly ordered state) is proposed to be no more than 240 emu/g at 300 K.