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The recent work is focused on the development of suitable amorphous ferromagnetic microwires (CoFe-based) for use in giant magneto-impedance (GMI) magnetic sensing cores. Rapid solidification route is used for the preparation of microwires via in-rotating water quenching technique. The potential of the CoFeSiBCr soft magnetic microwires for GMI based sensing core is investigated by using the driving frequency of MHz range. The GMI characteristics of the developed materials are carried out via impedance-mode. The performance of the magnetic sensor is studied based on its maximum GMI ratio, magnetic field sensitivity and noise spectrum. The experimental results reveal that the maximum GMI ratio, GMImax of about 650% and field sensitivity of around 802 V/T is achieved at ac driving frequency of 5 MHz with 3 mA driving current when annealed at 750 K for 5 min. The noise level of the optimized microwire can be obtained under 10 nT/√Hz@1 Hz while driven at 5 MHz. By means of its high operating frequency regime, high sensitivity, low noise level and simple methodology for sensing, the GMI microwires working in impedance-mode can be a potential candidate for commercial sensing applications such as microfluxgate sensors.

We have characterized the dependence of microstructure, and internal strain/stress on L 1 0 ordering in 40 nm thick FePt films with different initial stresses. The microstructural and crystallographic results indicate that defect annihilation and grain growth induced an increase in tensile stress of ~1 GPa before extensive L 1 0 ordering. The induced tensile stress can efficiently facilitate the nucleation of L 1 0 phase owing to that the volume expansion of L 1 0 ordering and atomic rearrangement neutralizes the tensile stress. If the as-deposited FePt film has a highly compressive state, the induced tensile stress will be canceled out and ordering is retarded, which results in a higher ordering temperature.

Magnetic properties and structure of sputter-prepared FePd thin films on the glass substrates by underlayering with refractory elements M (M = Nb, Mo, and W) have been studied. The structural analysis shows that FePd films have a (111) preferred orientation. All studied FePd films exhibit in-plane magnetic anisotropy. For single-layer FePd films, the coercivity ( $H_{c})$ and magnetic energy product [(BH) $_{\mathrm {max}}]$ are increased with annealing temperature ( $T_{a})$ and reached the maximum value of 1.3 kOe and 3.8 MGOe in the sample annealing at 600 °C. With the further increase of $T_{a}$ , magnetic properties drop rapidly. Dependence of magnetic hardening on $T_{a}$ can be explained by dominant solid reactions in different region of $T_{a}$ including ordering and grain growth. Interestingly, magnetic properties of L10-FePd are largely improved by underlayering with 5 nm-thick Nb, Mo, and W layers. Both the coercivity and energy product are significantly increased to 1.6 kOe and 4.9 MGOe for M = Nb, 2.5 kOe and 6.4 MGOe for M = Mo, and 3.3 kOe and 8.7 MGOe for M = W, respectively. Structural analysis suggests that this magnetic enhancement is related to both higher ordering degree and refined microstructure.

Structure and magnetic properties of the sputter-prepared FePt (160 nm) and FePt(160 nm)/Zr(10 nm) are studied. The films were deposited at room temperature and followed by a post annealing for magnetic hardening by L10-ordering. Distinct ordering processes are observed. In FePt films, extensive ordering occurs after annealing at Ta=700 °C and forms strong (111) texture. Hc increases to 8.5 kOe with a decrease in Mr of about 10%. In contrast, FePt/Zr samples orders at Ta=500 °C and results in drastic increase in Hc reaching 12.5 kOe with only 2.7% decrease in Mr. The difference in surface morphology of the two samples suggests that the low temperature ordering is a result of the nucleation promotion by Zr underlayer. The refined grain size strengthens the intergrain coupling resulting in greatly enhanced magnetic properties. The value of (BH)max for the film with Ta=500, 600, and 700 °C are 16.8, 20.0, and 19.6 MGOe, respectively. The maximum value is more than 110% higher than that of the FePt film annealed at Ta=700 °C (9.5 MGOe).

Perpendicularly magnetized CoPt films with L11 rhombohedral lattice were deposited on glass substrates with a Pt underlayer. The results show that the magnetic properties of CoPt films are substantially affected by post-annealing time (ta) and temperature (Ta) of Pt underlayer, as well as the thickness of Pt underlayer (tPt). Soft magnetic phase is formed as CoPt is directly deposited on the glass substrate at 350 °C. Besides, a very low coercivity (Hc) of 103 kA/m is obtained when ta, Ta, and tPt are 5 min, 300 °C, and 20 nm, respectively. Further varying ta, Ta, and tPt to 15 min, 350 °C, and 25 nm increases Hc to about 207 kA/m. The microstructural studies indicate that the size of CoPt grain is the key factor to determine the magnetic properties, which could be controlled by the formation conditions of Pt underlayer. In this study, the optimum deposition conditions for Pt underlayer to obtain L11 CoPt phase with high Hc are ta = 15 min, Ta = 350 °C, and tPt = 20-25 nm. Our study demonstrates that using a Pt underlayer/glass substrate can effectively replace the single-crystal substrate and also enhance Hc of CoPt film, which may increase the application potential of L11 CoPt film in the future.

L10-FePt(001) films with compositional gradient was proposed to realize the graded film with magnetic perpendicular anisotropy in this study. A hard magnetic layer of 5 nm-thick stoichiometry L10 FePt was initially deposited onto a glass substrate with a thin MgO underlayer. The hard layer exhibits strong (001) texture, island-type surface morphology, high perpendicular magnetic anisotropy (PMA), and large out-of-plane coercivity (Hc⊥) of about 20 kOe at room temperature (RT). A 5-nm-thick compositionally graded Fe-Pt layer was then deposited on the L10 FePt hard layer at deposition temperatures (Td) from 300 to 450°C. Good (001)-texture is retained in the graded layer and the island-type morphology is preserved when Td ≤ 400°C. A significant reduction in Hc⊥ from 20 to around 7 kOe was achieved. Besides, the graded films exhibit magnetically single-phase reversal behavior with a high anisotropy field (H0) of ~90 kOe. When Td > 400°C, PMA of the films was reduced due to the extensive diffusion between the Fe-rich graded and hard layers. Our proposed scheme demonstrate the feasibility of magnetic gradation induced by binary composition variation in FePt films, providing useful information for designing future ultrahigh magnetic recording media.

The effects of oxide on the microstructures and magnetic properties of L 1 1 CoPt thin films were studied by adding SiO 2 and MgO into CoPt thin films. The magnetic films were prepared by sputtering on MgO(111) substrates. SiO 2 is found to segregate at the CoPt grain boundary, hindering the formation of L 1 1 phase and degrading the perpendicular magnetic properties. Relatively, MgO nanoparticles precipitate in the CoPt matrix and stabilize the L 1 1 phase. The high perpendicular magnetic anisotropy is well preserved even with a large MgO content in L 1 1 CoPt–MgO composite film.

Fe49Pt51 thin films with a thickness of 20 nm were deposited by conventional dc co-sputtering at substrate temperature of 400 and 500°C before undergoing glow-discharge-induced ion bombardment at room temperature. The energy of the incident Ar ions was adjusted by applying a radio-frequency bias (Vb) in the range of 50 to 600 V. Significant abilities of ion bombardment in modifying both chemical ordering and surface morphology are demonstrated. With Vb in the range of 50 to 150 V, the bombardment smoothes the surface and enhances ordering by promoting surface diffusion. Bombarding at high Vb greater than 200 V evolves the surface morphology towards discontinuous island-like structure or rough pinhole topography and causes disordering by progressive etching. The magnetic properties can be tuned with the structural transformations by ion bombardment. The coercivity (Hc) can be increased from 0.57 to 0.75 MA/m by improving ordering for the films deposited at 400°C. On the other hand, the disordering and mass loss may produce the magnetic softening and drastically reduced magnetization.

A sample of nearby galaxies was built from the AKARI/FIS all sky survey cross-correlated withthe SDSS and GALEX surveys. The spectral energy distributions from 0.15 to 160 microns of thesegalaxies are analysed to study dust attenuation and star formation properties. The calibrationsof the amount of dust attenuation as a function of the IR-to-UV flux ratio and the FUV-NUVcolour are re-investigated: the former one is confirmed to be robust and accurate whereas the useof the FUV-NUV colour to measure dust attenuation is found highly uncertain. The current starformation rate given by the SED fitting process is compared to that directly obtained from theUV and total IR luminosities. It leads to an accurate estimate of dust heating by old stars. Weemphasize the importance of such a sample as a reference for IR selected star forming galaxies inthe nearby universe Key words: infrared: galaxies; ultraviolet: galaxies; dust: extinction1. INTRODUCTIONThe nearby universe remains the best laboratory tounderstand the physical properties of galaxies and isa reference for any comparison with high redshift ob-servations. The all sky (or very large) surveys thathave been performed from the ultraviolet (UV) to thefar-infrared (far-IR) provide us with large datasets andvery large wavelength coverage to perform a referencestudy. The broad-band spectral energy distribution(SED) of a galaxy represents the combination of theemission from both stars of all ages and interstellardust that interact in a complex way by means of theabsorption and scattering of the stellar light by dustgrains. The stars emit from the UV to the near-IRwhereas the mid and far-IR emission comes from inter-stellar dust heated by the stellar emission. By compar-ing data with models, one can attempt to derive somephysical parameters related to the star formation his-tory and dust attenuation in a homogeneous way andsimultaneously for all galaxies of a given sample. Withthe availability of mid and far-IR data for large samplesof galaxies, we can combine stellar and dust emissionto analyse SEDs and deduce accurate star formationrates (SFRs).We investigate the properties of nearby galaxies by se-lecting a sample of objects that is as large as possible,observed as part of the

We have characterized the dependence of residual strain/stress on annealing process (post- and in-situ annealing) in single-layer FePt films prepared by sputtering onto amorphous glass substrates. A remarkable difference of evolutions in residual strains between post-andin-situ annealed samples was observed by Sin2 ψ method using synchrotron radiation. The onset of ordering temperature for both series samples is almost identical (~ 350 °C), verified by x-ray diffraction. Crystalline domain size, measured by x-ray peak breadths, of FePt films indicates a difference between these two series samples, which is associated with evolution of residual strain. We believe that the dynamic stress relaxation is the major factor in discrepancy of the residual stress behavior, since the atomic mobility of adatoms during film deposition for in-situ annealing samples are much higher than that for post-annealed films. It is further deduced that residual strain mechanisms may influence the ordering behaviors and related microstructure of FePt films.

Room-temperature-deposited FePt thin films with thickness (t) ranged from 5 to 100 nm treated by rapid-thermal annealing (RTA) were studied. With annealing condition of 900°C for 60 seconds at heating rate of 80° C/sec., a metastable phase of FePt was observed in the films with t ≥ 40 nm. The phase is chemically ordered with a face-centered-cubic (fcc) structure. The lattice parameter of it is found identical to the planar spacing of L10 (100). The metastable structure is dominant in the film with t = 40 nm and gradually replaced by L10 phase with increasing t. The fcc phase is soft magnetic with saturation magnetization similar to that of disordered FePt. Drastic changes were also observed in surface morphology. The results infer the connection between the metastable transformation and internal strain. The formation of the fcc structure is sensitive to processing parameters except t . Slower heating rate, lower annealing temperature, and longer annealing time, tend to suppress the formation of it. The interesting findings provide additional knowledge for FePt thin films.

Development of (001) texture in FePt thin films deposited on glass substrates with different thickness (t) treated by rapid thermal annealing (RTA) is studied. A critical thickness of 30 nm is characterized: below which the (001) preferred orientation of the films develops with increasing t ; when t >; 30 , the films become isotropic. Remarkable perpendicular anisotropy in magnetic properties is achieved in the 30 nm thick sample with the best (001) texture. Discontinuous changes are also observed in surface morphology, microstructure, magnetic domain structure, and internal stress. Direct evidences are presented relating the formation of (001) texture to abnormal grain growth. The internal stress/strain analysis indicates that the residual tensile (σ) stress is proportional to the degree of (001) preferred orientation. A large value of σ of about 8.9 GPa is obtained in the film with t = 30, suggesting the driving force forming the texture.

Samples with glass/CrRu(90 nm)/Pt(2 nm)/FePt(20 nm) film structure were sequentially planetary-sputtered at an in situ heating temperature of 350degC to investigate the effect of sputtering rate on the ordering of L10-FePt (001) films. The degree of chemical ordering was enhanced by lowering the sputtering rate of the FePt layer. The slow sputtering process also promoted the formation of the (001) preferred orientation by improving epitaxial growth, because the thickness of the Fe and Pt layers in each revolution become smaller as the sputtering rate was reduced. Therefore, the diffusion lengths of the Fe and Pt atoms required for migration into the L10 lattice sites became shorter. The sputter parameters can be optimized to form ordered FePt (001) films with a high magnetic squareness ratio ( 0.8) and large coercivity at 300degC, which is 50degC lower than in previous reports. The results herein provide useful information on the fabrication of FePt films with perpendicular anisotropy at low temperatures in media use.

CoPt and CoPt/Au films prepared by magnetron sputtering were studied in this paper. The films were deposited at room temperature followed by a post annealing at temperatures (T a) from 400degC to 800degC. Ordering of the CoPt and CoPt/Au films occurred at T a = 600degC and 500degC, respectively, which results in magnetic hardening. With the increase of T a up to 700degC, coercivity of the both films increased to a maximum value of about 12 kOe. As T a reached 800degC, a drastic magnetic softening occurs in both samples; meanwhile, the diffraction data indicate a corresponding phase change from tetragonal to cubic. Scanning electron microscopy results revealed an intensive grain growth from 70 nm at 700degC to 160 nm at 800degC for CoPt/glass film and from 110 nm at 700degC to 250 nm at 800degC for CoPt/Au/glass sample. The relation between the abnormal phase change and intensive grain growth indicates that the formation of the cubic phase is driven by large biaxial tensile stress. Further investigations support this explanation and reveal that the cubic phase may be chemically ordered.

This paper explores (FePt)100 - x-(MgO)x films with x = 0 - 6.13, deposited on an MgO underlayer at elevated temperatures by sputtering. The films exhibit good (001) texture and perpendicular anisotropy. The effects of adding MgO are summarized as follows: (1) the (001) alignment is degraded, increasing the in-plane squareness ratio (S// ); (2) a linear dilution of magnetization at an applied field of 6 Tesla was observed; and (3) a critical MgO content of 1 vol. % was found for chemical ordering, microstructure, and anisotropic field (H k). Below this critical content, the ordering of FePt and its microstructure remain similar to those with x = 0 but with a markedly enhanced H k. As x exceeded 1 vol. %, the ordering declined linearly with increasing MgO content. Additionally, a well-defined granular structure was formed and H k was reduced. The decrease in the lattice constant along the c-axis as x increased between 0 and 1 vol. % reveals that the enhancement of H k is related to the relaxation of the residual strain/stress that originates from the ordering transformation of FePt. Adding the proper amount of MgO improved the magnetic properties of (001)-textured FePt.

Fe53Pt47 and Fe58Pt42 thin films with 300 nm in thickness prepared using magnetron sputtering were investigated. The films were deposited on heated glass substrates and annealed at 400degC and 800degC for different time. Single phase FePt films with similar chemical ordering but different substructure size were produced in the two series of samples. The effect of microstructure refinement results in significant enhancement in remanence (Mr) of about 38.1% and 30.8% in the Fe53Pt47 and Fe58Pt42 films, respectively. The energy product, (BH)max, also showed a large increase of 25% and 72%; the maximum value of the two series of films are 16.2 MGOe and 19.6 MGOe, respectively. The large (BH)max was found to originate from the enhancement of M r and steep slope of demagnetization curve at coercive point (alpha). As the theoretical predictions, in an isotropic magnet, the magnetic moments in the transition region of magnetization near grain boundary are easy to be aligned by applied field. In this study, it is found that by increasing the magnetic transition region through microstructure refining, the remanence can be effectively enhanced meanwhile facilitate the collective magnetic reversal. Domain structure confirms that the refinement of microstructure effectively reduces the domain size.

Fe100-xPtx (x = 20, 25, and 30) thin films with nominal thickness 50 nm were prepared by radio-frequency (RF) magnetron sputtering onto glass substrates. Crystallographic structure and magnetic properties of such films were investigated by varying Fe content, annealing temperature (400-700degC), and heating process. Crystallographic structure obtained by X-ray diffraction (XRD) indicated that ordering of L12 Fe3Pt phase takes place for Fe75Pt25 postannealed above 400degC. Ordering parameter of the Fe75Pt25 sample increases from 0.29 to 0.94 as annealing temperature rises from 400degC to 700degC. Saturation magnetization 1270 emu/cm3 was obtained in Fe75Pt25 films annealed at 700degC. Fe70Pt30 films annealed at 700degC show similar characteristics with those of Fe75Pt25, while Fe80Pt20 films exhibit paramagnetism due to disordered Fe-rich face-centered cubic (fcc) structure. Postannealing seems necessary for formation of pure L12 Fe3Pt phase while in situ annealing leads to formation of a metastable tetragonal Fe3Pt phase, as confirmed by XRD.

Microstructure, crystal structure, and magnetic properties of the Fe49-xCoxPt51 (x = 0, 0.7, 1.3, 2.2) thin films deposited on glass substrates were investigated. The addition of Co was found to enhance the magnetization of the FePt L1(0) phase, thus increases the energy product, (BH)(max). A maximum value of (BH)(max) of 18.4 MGOe was obtained in the sample with x = 1.3 annealing at 500 C. The microstructure results indicated that significant grain refining was found in the x = 2.2 sample, which reduced from averagely 60 rim for the x = 0.0 similar to 1.3 sample to 30 nm. The concentration of Co was uniform in the Fe-Pt-Co film except x = 1.3 film, in which small grains with 1020 nm in diameter showed higher percentage of Co. Corresponding to the compositional inhomogeneity, X-ray structural analysis revealed that the x = 1.3 film contained about 20 vol. % disordered fcc phase, which was much higher than the other composition samples (

With the goal of constructing Star-Formation Rates (SFR) from AKARI Infrared Camera (IRC) data, we analyzed an IR-selected GALEX-SDSS-2MASS-AKARI(IRC & Far-Infrared Surveyor) sample of 153 nearby galaxies. The far-infrared fluxes were obtained from AKARI diffuse maps to correct the underestimation for extended sources raised by PSF photometry. SFRs of these galaxies were derived using the SED fitting program CIGALE. In spite of complicated features contained in these bands, both the S9W and L18W emissions correlate with the SFR of galaxies. The SFR calibrations using S9W and L18W are presented for the first time. These calibrations agree well with previous work based on Spitzer data within the scatter, and should be applicable to dust-rich galaxies.

FePt/SiO2 nanogranular thin films have been prepared by molecular-beam epitaxy system on MgO (001) substrates with the method of insertion dual SiO2 layers into Fe/Pt multilayer films. We report the relationships between the inserting thickness of SiO2 layers and the microstructural and magnetic properties of FePt thin films. It indicated the nanogranular FePt thin films were successfully formed by inserting amorphous SiO2 layers into the Fe/Pt films. The reduction of grain/domain size and isolation of FePt particles can be achieved by such insertion and maintain (001) texture. The average grain size of FePt films with 5-nm SiO2 insert layers is estimated to be around 8 nm, while domain rotation is enhanced depicting a decoupling of intergrain interaction. The isolated grains are less magnetically coupled in the rotation mode and the reversal of magnetization is more independent

Effect of Ag segregation on magnetic and structural properties of (FePt)77 Ag23 single-layer films were studied. Thin films were first sputtered on the heated glass substrates and cooled to room temperature, a post annealing at temperatures (Tp) from 200 degC to 400 degC for 60 min was then applied. Ll0 structure formed as substrate temperature (Ts) equals to 600 degC and 700 degC. For those ordered films, Ag was observed to precipitate as particles on the film surface and grow with the increasing Ts. After post annealing at 400 degC for 60min, those silver particles dissolved into the film, leading to changes in reversal behavior. The optimum condition is obtained in the Ts=600degC, Tp=400degC sample. Drastic reduction in coercive squareness ratio (from >0.8 to 0.41) and enhanced coercivity (from 4.7 to 6.4 kOe) indicate the reversal behavior alters from cooperative to independent. Negative deltaM curve suggests that this independent rotation results from the reduction of exchange interactions

An accurate estimation of the star formation-related properties of galaxies is crucial for understanding the evolution of galaxies. In galaxies, ultraviolet (UV) light emitted by recently formed massive stars is attenuated by dust, which is also produced by star formation (SF) activity, and is reemitted at mid- and far- infrared (IR) wavelengths. In this study, we investigate the star formation rate (SFR) and dust extinction using UV and IR data. We selected local galaxies which are detected at AKARI FIS 90 um and matched the IRAS IIFSCz 60 um select catalog. We measured FUV and NUV flux densities from GALEX images. We examined the SF and extinction of Local galaxies using four bands of AKARI. Then, we calculated FUV and total IR luminosities, and obtained the SF luminosity, L_{SF}, the total luminosity related to star formation activity, and the SFR. We find that in most galaxies, L_{SF} is dominated by L_{dust}. We also find that galaxies with higher SF activity have a higher fraction of their SF hidden by dust. In fact, the SF of galaxies with SFRs >20 M_{sun}/yr is almost completely hidden by dust. Our results boast a significantly higher precision with respect to previously published works, due to the use of much larger object samples from the AKARI and GALEX all sky surveys., 9 pages, 12 figures, accepted for publication in Earth, Planets, and Space, A few minor corrections, and a reference added

We have investigated the effect of interfacial diffusion on the magnetic properties of Au∕Fe51Pt49 bilayer thin films. The samples were prepared in two stages. First, an ordered Fe51Pt49 continuous thin film was sputtered on a quartz substrate. Then an aurum cap layer was deposited onto the Fe51Pt49 film at room temperature, followed by a postannealing at 300–800°C to promote the interfacial diffusion. A high coercivity of 23.5kOe was achieved in the isotropic polycrystalline FePt-based film. Transmission electron micrographs indicate that the bilayer sample exhibits Ll0 ordered FePt grains with a diameter of about 20nm, which were partially isolated by Au phase. We consider that the isolation of FePtLl0 grains and the grain refining effect can be two contributory factors for the enhanced coercivity.

Far-ultraviolet (FUV) and far-infrared (FIR) luminosity functions (LFs) of galaxies show a strong evolution from $z = 0$ to $z = 1$, but the FIR LF evolves much stronger than the FUV one. The FUV is dominantly radiated from newly formed short-lived OB stars, while the FIR is emitted by dust grains heated by the FUV radiation field. It is known that dust is always associated with star formation activity. Thus, both FUV and FIR are tightly related to the star formation in galaxies, but in a very complicated manner. In order to disentangle the relation between FUV and FIR emissions, we estimate the UV-IR bivariate LF (BLF) of galaxies with {\sl GALEX} and {\sl AKARI} All-Sky Survey datasets. Recently we invented a new mathematical method to construct the BLF with given marginals and prescribed correlation coefficient. This method makes use of a tool from mathematical statistics, so called "copula". The copula enables us to construct a bivariate distribution function from given marginal distributions with prescribed correlation and/or dependence structure. With this new formulation and FUV and FIR univariate LFs, we analyze various FUV and FIR data with {\sl GALEX}, {\sl Spitzer}, and {\sl AKARI} to estimate the UV-IR BLF. The obtained BLFs naturally explain the nonlinear complicated relation between FUV and FIR emission from star-forming galaxies. Though the faint-end of the BLF was not well constrained for high-$z$ samples, the estimated linear correlation coefficient $\rho$ was found to be very high, and is remarkably stable with redshifts (from 0.95 at $z = 0$ to 0.85 at $z = 1.0$). This implies the evolution of the UV-IR BLF is mainly due to the different evolution of the univariate LFs, and may not be controlled by the dependence structure., Comment: 10 pages, 7 figures, Earth, Planets and Space, in press

AKARI/Infrared Camera (IRC) Point Source Catalog provides a large amount of flux data at {\it S9W} ($9\ {\rm \mu m}$) and {\it L18W} ($18\ {\rm \mu m}$) bands. With the goal of constructing Star-Formation Rate(SFR) calculations using IRC data, we analyzed an IR selected GALEX-SDSS-2MASS-AKARI(IRC/Far-Infrared Surveyor) sample of 153 nearby galaxies. The far-infrared fluxes were obtained from AKARI diffuse maps to correct the underestimation for extended sources raised by the point-spread function photometry. SFRs of these galaxies were derived by the spectral energy distribution fitting program CIGALE. In spite of complicated features contained in these bands, both the {\it S9W} and {\it L18W} emission correlate with the SFR of galaxies. The SFR calibrations using {\it S9W} and {\it L18W} are presented for the first time. These calibrations agree well with previous works based on Spitzer data within the scatters, and should be applicable to dust-rich galaxies., Comment: PASJ, in press

The nearby universe remains the best laboratory to understand physical properties of galaxies and is a reference for any comparison with high redshift observations. The all sky (or very large) surveys performed from the ultraviolet (UV) to the far-infrared (far-IR) gives us large datasets with a very large wavelength coverage to perform a reference study. We want to investigate dust attenuation characteristics as well as star formation rate (SFR) calibrations on a sample of nearby galaxies observed over 13 bands from 0.15 to 160 microns. A sample of 363 galaxies is built from the AKARI /FIS all sky survey cross-correlated with SDSS and GALEX surveys. Broad band spectral energy distributions are fitted with the CIGALE code optimized to analyze variations in dust attenuation curves and SFR measurements and based on an energetic budget between the stellar and dust emission. Our galaxy sample is primarily selected in far-IR and mostly constituted of massive, actively star forming galaxies. There is some evidence for a dust attenuation law slightly steeper than that used for starburst galaxies but we are unable to constrain the presence or not of a bump at 220 nm. We confirm that a time dependent dust attenuation is necessary to perform the best fits. Various calibrations of the dust attenuation in the UV as a function of UV-optical colours are discussed. A calibration of the current star formation rate combining UV and total IR emissions is proposed with an accurate estimation of dust heating by old stars: for the whole sample 17 % of the total dust luminosity is not related to the recent star formation, 13 pages, 20 figures, published in Astronomy and Astrophysics

We present the results of the near-infrared (IR) spectroscopy of nine IRAS galaxies (NGC 1266, NGC 1320, NGC 2633, NGC 2903, NGC 3034, Mrk 33, NGC 7331, NGC 7625, NGC 7714) with the ISLE imager and spectrograph mounted on the Okayama Astrophysical Observatory 1.88 m telescope. [Fe II] 1.257 um and Pa beta emission lines were observed for the whole sample while H2 2.121 um and Br gamma lines were additionally obtained for two sources, whose flux ratios are used as a diagnostic tool of dominant energy sources of the galaxies. We find that the nucleus of NGC 1266 is most likely a low ionization nuclear emission-line region (LINER), while NGC 2633 and NGC 2903 possibly harbor active galactic nuclei (AGNs). No AGN or LINER signal is found for other objects. In addition, we find the spectral features which is indicative of some unusual phenomena occurring in the galaxies, such as the large [Fe II] line widths compared to the local escape velocity in NGC 1266. The present work shows the potential ability of the ISLE to shed new light on the nature of infrared galaxies, either through a statistical survey of galaxies or an exploration of spectral features found in individual objects., Comment: Accepted for publication in PASJ

International audience; Aims. We explore spectral energy distributions (SEDs), star formation (SF), and dust extinction properties of galaxies in the Local Universe. Methods. The AKARI all-sky survey provided the first bright point source catalog detected at 90 mu m. Beginning with this catalog, we selected galaxies by matching the AKARI sources with those in the IRAS point source catalog redshift survey. We measured the total GALEX FUV and NUV flux densities with a photometry software we specifically developed for this purpose. In a further step we matched this sample with the Sloan digital sky survey (SDSS) and 2 micron all sky survey (2MASS) galaxies. With this procedure we obtained a basic sample which consists of 776 galaxies. After removing objects whose photometry was contaminated by foreground sources (mainly in the SDSS), we defined the “secure sample” which contains 607 galaxies. Results. The sample galaxies have redshifts of less than or similar to 0.15, and their 90-mu m luminosities range from 10(6) to 10(12) L-circle dot, with a peak at 10(10) L-circle dot. The SEDs display a large variety, especially more than four orders of magnitude at the mid-far-infrared (M-FIR), but if we sort the sample with respect to 90 mu m, the average SED shows a coherent trend: the more luminous an SED at 90 mu m, the redder the global SED becomes. The M-r-NUV-r color-magnitude relation of our sample does not show bimodality, and the distribution is centered on the green valley. We established formulae to convert the FIR luminosity from the AKARI bands to the total IR (TIR) luminosity L-TIR. The luminosity related to the SF activity (L-SF) is dominated by L-TIR even if we take into account the FIR emission from dust heated by old stars. At a high SF rate (SFR) (\textgreater 20 M-circle dot yr(-1)), the fraction of the directly visible SFR, SFRFUV, decreases. We also estimated the FUV attenuation A(FUV) from the FUV-to-TIR luminosity ratio. We examined the L-TIR/L-FUV-UV slope (FUV-NUV) relation. The majority of the sample has L-TIR/L-FUV ratios five to ten times lower than expected from the local starburst relation, while some luminous IR and all the ultraluminous IR galaxies of this sample have higher L-TIR/L-FUV ratios. We found the attenuation indicator L-TIR/L-FUV correlated to the stellar mass of galaxies, M-*, but not with a specific SFR, SFR/M-*. Conclusions. Together, these results show that the AKARI survey gives a representative sample of the local SF galaxies which will be a comprehensive local standard of their various properties to be compared with, for instance, high-z SF galaxies.

Effect of Ba substitution on the multiferroic properties of non-epitaxially grown polycrystalline Bi1−xBaxFeO3 (BBFO) films on refined Pt(111) electrode buffered glass substrates is studied. The structural analysis shows that a pure perovskite phase is present for BBFO films (x = 0.05-0.15), and (110) preferred orientation is developed for films with high x = 0.15. The grain size and surface roughness are reduced with increasing x. All studied BBFO films show desired ferroelectric and ferromagnetic properties. The good ferroelectric properties with the remanent polarization (2Pr) of 36-70 μC/cm2 and electrical coercive field (Ec) of 318-570 kV/cm are attained. On the other hand, the substitution of Ba2+ for Bi3+ in the A site of the BFO crystal structure can effectively enhance the ferromagnetic properties with magnetization (Ms) of 9.4-13.9 emu/cm3 and coercivity (Hc) of 1216-1380 Oe. The ferromagnetic and ferroelectric properties and leakage behavior as functions of Ba content x are discussed.

Starting from an infrared selected GALEX-SDSS-2MASS-AKARI sample of local star forming galaxies, we built mock samples from redshift 0 to 2.5 to investigate star formation rate (SFR) calibrations using WISE luminosities. We find W3 and W4 band fluxes can indicate SFRs with small scatters when the rest-frame wavelengths are longer than . When the wavelength becomes shorter, the observed luminosities are more tightly connected to the emission of old stellar populations than dust, therefore lose the reliability to trace the SFR. The current SFR calibrations are consistent with previous studies.

Phase structure and ferroelectric properties of BiFeO3 (BFO) films grown on Pt(111) buffered glass substrates at various growth temperatures and oxygen pressures have been studied. The optimization of the 20-nm-thick Pt(111) bottom electrode enables BFO films to form perovskite single phase structure at reduced temperatures between 400–500 °C. Microstructure of fine grains and smooth surface is obtained, which is favorable for applications. Multiferroic properties including 2Pr of 15.1–124 μC/cm2, Ec of 351–680 kV/cm, and Ms of 5–8 emu/cm3 are achieved within the oxygen pressure range of 10–75 mTorr. The optimized ferroelectric properties are comparable to the reported values of BFO samples using Si and MgO single crystal substrates. The results of this study may broaden the possibility of the use of BFO films.Phase structure and ferroelectric properties of BiFeO3 (BFO) films grown on Pt(111) buffered glass substrates at various growth temperatures and oxygen pressures have been studied. The optimization of the 20-nm-thick Pt(111) bottom electrode enables BFO films to form perovskite single phase structure at reduced temperatures between 400–500 °C. Microstructure of fine grains and smooth surface is obtained, which is favorable for applications. Multiferroic properties including 2Pr of 15.1–124 μC/cm2, Ec of 351–680 kV/cm, and Ms of 5–8 emu/cm3 are achieved within the oxygen pressure range of 10–75 mTorr. The optimized ferroelectric properties are comparable to the reported values of BFO samples using Si and MgO single crystal substrates. The results of this study may broaden the possibility of the use of BFO films.

Merger processes play an important role in galaxy formation and evolution. To study the influence of merger processes on the evolution of dust properties and cosmic star formation rate, we investigate a local sample of major merger galaxies and a control sample of isolated galaxies using GALEX ultraviolet (UV) and Spitzer infrared (IR) images. Through a statistical study, we find that dust attenuation in merger galaxies is enhanced with respect to isolated galaxies. We find this enhancement is contributed mainly by spiral galaxies in spiral-spiral (S-S) pairs, and increases with the increasing stellar mass of a galaxy. Combining the IR and UV parts of star formation rates (SFRs), we then calculated the total SFRs and specific star formation rates (SSFRs). We find the SSFRs to be enhanced in merger galaxies. This enhancement depends on galaxy stellar mass and the companion's morphology, but depends little on whether the galaxy is a primary or secondary component or on the separation between two components. These results are consistent with a previous study based only on IR images. In addition, we investigate the nuclear contributions to SFRs. SFRs in paired galaxies are more concentrated in the central part of the galaxies than in isolate galaxies. Our studies of dust attenuation show that the nuclear parts of pairs most resemble ULIRGs. Including UV data in the present work not only provides reliable information on dust attenuation, but also refines analyses of SFRs., 21 pages, 21 figures

This study investigates the effect of glow-discharge induced ion bombardment (IB) on low-temperature ordering in FePt films. H, He, and Ar ions are used. Extensive ordering occurs at 300 °C via IB at energy below sputtering threshold, achieving the degree of ordering comparable to 400 °C of thermal annealing. Distinct ordering mechanism is identified. H-IB films undergo grain-growth-dominated transformation, similar to thermal annealing. However, Ar-IB modifies diffusion behavior causing nucleation-controlled process, realizing high ordering and refined microstructure simultaneously. The mechanisms can be thoroughly elucidated by diffusion-modified nucleation-growth kinetics. The results significantly contribute to efforts in microstructure engineering for advanced thin film devices.

The symmetries of CoPt thin films in different phases, including disordered A1, ordered L11, and L10 were examined by making measurements along the (10.1) diffraction rod. The films were deposited by sputtering on MgO(111) substrates at different temperatures (Ta). The stacking sequence of close-packed atomic planes in 50 nm-thick samples with Ta ≥ 200 °C was identified as ABCABC, indicating that the distribution of defects in the film was random, so the symmetry was preserved with increasing Ta. In the RT-prepared film, a considerable amount of (∼62.9 vol.%) disordered CoPt with hexagonal symmetry was detected, vanishing as Ta increased. Defect-induced modification of symmetry was observed in the L11 film as its thickness was reduced to 10 nm. A pseudo-hcp component of around 7.1 vol.% was present in the film, as a result of the periodic distribution of defects. The defects in the structure may also explain the broadened magnetic alignment.

Magnetic properties of sputter-deposited ferromagnetic (FM)/BiFeO3 (BFO) films on Pt/Ti/SiO2/Si(100) substrate (FM = Co and Fe) have been investigated. Isotropic perovskite BFO single phase is obtained for 200-nm-thick BFO films deposited at 300–450 °C and BFO films at 400 °C with thickness of 50–400 nm. Large exchange bias field (HEB) of 308–400 Oe and coercivity (Hc) of 1201–3632 Oe at RT are obtained for polycrystalline Co/BFO bilayers. The roughened surface induced by high deposition temperature and increasing thickness of BFO layer enhances localized shape anisotropy of FM layer, resulting in the increase of Hc the improved crystallinity and roughened surface of BFO/Co interface might be responsible for the HEB enhancement. Additionally, comparison on the HEB in polycrystalline Co/BFO and Fe/BFO systems is also discussed.

This study examines L10 FePt (001) hard magnetic films that were coated with a layer having graded perpendicular magnetic constant (Ku) and with a disordered FePt soft layer on glass substrates. The 5 nm-thick hard layer exhibits a clear (001) texture, large perpendicular magnetic anisotropy (PMA), and an island-like morphology with particle size of 15–25 nm. The deposition of the graded or soft layer with a thickness of 5–15 nm does not change the particle size. The graded and hard/soft samples both exhibit reduced out-of-plane coercivity (Hc⊥) but their reversal behaviors differ. Strong exchange coupling appears between the hard and graded layers, maintaining high PMA. However, hard/soft films exhibit weak coupling such that the film becomes in-plane anisotropic when the thickness of the soft layer exceeds 5 nm. The investigations of magnetic domain structures further reveal different magnetic coupling configurations between different types of films. The results herein are consistent with theoretical pr...

Structure and magnetic properties of L11 CoPtCu thin films sputter-deposited on glass substrates were studied. Perpendicular coercivity (Hc⊥) was largely enhanced by the replacement of Co with Cu with x = 23 and 26, the magnetic properties obtained was better than the film grown on MgO(111) substrates. The enhancement of Hc⊥ existed in a wide range of film thickness from 2 to 40 nm. A maximum value of Hc⊥ of 2.7 kOe appeared in the films with thickness of 4 nm. The results of surface morphology indicated that the random distribution of the in-plane orientation of L11 grains induced by Pt(111) underlayer may create magnetic inhomogeneities acting as pinning site to domain walls, providing additional impedance for domain wall motion.

This study elucidates the magnetic properties of [Ta/Co60Fe20B20/MgO]5 as functions of thickness of each layer. Its perpendicular magnetic anisotropy (PMA) is found to depend strongly on the thickness of the MgO (tMgO) and Co-Fe-B (tCoFeB) layers. The Ta/CoFeB interface is critical to inducing PMA. A maximum room-temperature (RT) anisotropic energy (KuRT) of about 1 × 106 erg/cm3 and an anisotropic field (HkRT) of 4.7 kOe are obtained in the RT-prepared multilayered sample with tMgO = 1.0, tCoFeB = 1.3, and thickness of layer tTa = 10 nm. These values are comparable to the published values for Co60Fe20B20 after optimized field annealing. In this investigation, post-annealing has a more complicated effect on PMA in a multilayered structure than in a single or a double Co-Fe-B layer, both of which structure have been examined elsewhere. This result may be explained by the competing effects of the thermal process, which is an improvement of the crystallinity of Co-Fe-B and roughening of the interface.

Single-layered FePt thin films were deposited on glass substrates and subsequently annealed at 800 °C for various times in a rapid thermal annealing (RTA) furnace. Near-fully-L10-ordered FePt films were obtained after RTA. The accumulation of the intrinsic tensile stress is mainly contributed by the densification reaction, which leads to the development of (001) preferred orientation. The relief of the tensile stress predominantly stems from the microstructural variation (from continuous to interconnected network state), resulting in a reduction of (001) texture. Enhanced perpendicular magnetic and crystalline anisotropy was obtained for the films annealed for 900 s, confirmed by a high Lotgering orientation factor of 0.99 and differential squareness of 0.5. The results provide direct evidence that intrinsic tensile stress prompts the (001) preferred orientation through suggested strain-induced grain growth.

The stress state of FePt thin films deposited at room temperature was controlled within the range from 1.01 GPa compressive to 0.18 GPa tensile before taking rapid thermal annealing (RTA). After the order–disorder transformation triggered by RTA at temperatures (Ta) from 650 to 800 °C for 5 min, the tensile-stressed films exhibit significant preferred orientation of (001) of L10 structure. However, the compressive-strained ones show isotropic texture. Strong (001) texture with high Lotgering orientation factor of 0.9 is obtained at Ta = 800 °C, resulting in enhanced perpendicular magnetic anisotropy. The results provide direct evidence of stress-induced (001) texture, which could be significant for future applications.

This study investigates structural and magnetic properties of the (Co50-xCux)Pt50 films deposited on the MgO(111) substrate. Experimental results indicate that adding Cu significantly improves the alignment of L11[111] and decreases the structural defects of the epitaxial films. Additionally, a large increment of an order of magnitude in out-of-plane coercivity (Hc⊥) from 0.2 to 2.2 kOe is achieved when x is increased from 0 to 23. Such an increase accompanies a reduction of in-plane coercivity (Hc||) from 1.5 to less than 0.1 kOe. The enhancement in Hc⊥ is attributed to the domain wall pinning effect induced by compositional segregation of Cu and Co. This study provides an effective approach to optimize the perpendicular magnetic properties of L11 CoPt.

Equiatomic CoPt and FePt thin films grown on MgO(111) substrates at temperatures (Ta) from room temperature (RT) to 400 °C were studied. Distinct phase evolution was observed. In CoPt films, a metastable phase of L11 appears at Ta = 250 °C prior to the formation of thermodynamic equilibrium L10 phase; whereas no intermediate structure is found in the FePt films. Good epitaxial growth of CoPt films can be obtained at low Ta before ordering. However, in FePt films, high quality epitaxy appears after the occurrence of L10 ordering. Either L11 or L10 ordering induces magnetic hardening. Perpendicular magnetic anisotropy was obtained in the L11 films, yet the L10 sample exhibited isotropic magnetism. Corresponding evolution in magnetic domain structure was also reported.

FePt(20 nm)/Cr(200 nm) bilayer films were deposited on 300°C-heated glass substrate in order to study the sputtering rate effect on ordering process and growth mechanism of FePt films. The sputtering rate of FePt layer (Rm) was adjusted within the range from 0.1 to 2.0 nm/min.. X-ray results show a high order parameter of ~0.8 in the sample with Rm = 0.1 nm/min and a disordered phase of FePt in the film with Rm = 2.0 nm/min. As Rm = 0.1 nm/min., the orientation of FePt lattice aligns along the Cr(002) to develop (001)-oriented FePt. However, an isotropic orientation is observed in FePt layer as Rm = 2.0 nm/min.. In the case of low deposition rate, the growth of the film is dominated by surface diffusion. In contrast, the process of bulk diffusion dominates in the rapidly-deposited film. The activating barrier of bulk diffusion is about an order of magnitude larger than that of surface diffusion leading to the appearance of disorder structure and isotropic orientations at high sputtering rate. In this study, FePt layers with well-developed (001) texture and high chemical ordering can be fabricated via surface diffusion mechanism at 300°C. Our result merits the use of FePt magnetic layer for magnetic recording media in the future.

Initial stress (σi) of a room-temperature deposited FePt films was manipulated to study the order-disorder transformation. We observed that, while σi was increased from −1.01 (compressive) to 0.18 GPa (tensile), the phase transformation activation energy decreased from 0.387 to 0.23 eV/atom. This causes a reduction in ordering temperature of about 100 °C. We also found that densification induces an increase in tensile stress of about 1 GPa before ordering. In the films with small σi, strong tension facilitates the nucleation of L10 FePt; however, if highly compressive σi cancels the densification tension, ordering is retarded causing higher ordering temperature.

Fe48Pt52 thin films with a thickness of 50 nm were deposited at room temperature before undergoing glow-discharge-induced ion bombardment at 300 °C for 1 h. The energy of the incident ions was adjusted by applying a radio-frequency bias (Vb) from 200 to 600 V. H2, He, and Ar were used as the working gases. Significant ordering enhancement was only found in the H-ion bombarded films. The coercivity of such films is greatly increased from 0.5 kOe, for the sample without any bias, to around 8 kOe at Vb=200–600 V, which result is similar to that for a film annealed at 400 °C in a vacuum. This result suggests that H-ion bombardment has the effect of a 100 °C increase in annealing temperature. Microstructural studies reveal that the average grain size of the H-ion bombarded films is about 30 nm, which is much smaller than that of 400 °C-annealed films. The film thickness of He-ion bombarded samples decreases linearly as Vb increases because of the intensive sputtering effect. Under Ar-ion bombardment, most of t...

FePt thin films with the addition of Ag layers have been fabricated in order to study the microstructure and magnetic properties via a molecular beam epitaxy technique on MgO (001) single-crystal substrates at 350°C. The enhancement of the coercivity is due to the film structures changed from continuous state to an isolated particulate character, not an ordering enhancement of FePt films with Ag addition. Studies of angular dependent coercivity show a tendency of a domain-wall motion shift toward rotation of reverse-domain type with the addition of Ag layers into the FePt films. The intergrain interaction was confirmed from the Kelly-Henkel plot that indicated FePt films with Ag addition can lead to the reduction of intergrain exchange coupling.