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Low temperature radioluminescence and thermoluminescence spectra of ZnO track numerous changes produced by copper ion implantation into the surface layer. A significant, but unexpected, feature is that the bulk crystal becomes modified by the stress generated in the surface layer. This is reflected by the energy of intrinsic band gap emission. There are also differences in the spectra and peak temperatures of the thermoluminescence components, consistent with such a structural relaxation. The copper implant layer is both absorbing and reflective, so this introduces major distortions on the radioluminescence component from the bulk region, since the bulk luminescence signals are transmitted through, or reflected from, the implant layer. The temperature dependence of the spectra includes anomalies that are typical of changes driven by phase transitions of nanoparticle inclusions. Overall, the features of bulk relaxation, spectral distortion, and detection of nanoparticle inclusions are rarely considered for ion implanted luminescence studies, but the data suggest they are almost inevitable in a wide range of implanted materials. [ABSTRACT FROM AUTHOR]

Perpendicular exchange coupled composite structures were prepared, utilizing L10-FePt as the magnetic hard layer and [Co/Ni]N multilayers as the soft layer. Sharp reduction of the switching field was observed with increasing periodic number N of [Co/Ni]N multilayers. By inserting a thin Pt interlayer between L10-FePt and [Co/Ni]N layers, it is found that in order to get the best of exchange coupled composites, different interlayer coupling stiffness was required in the composites with different soft layer thickness. Furthermore, the angular variation of the coercivity and remanent coercivity shows high angular tolerance to applied field angle, and reveals the evolution of magnetization reversal from incoherent rotational mode to dominant wall motion with increasing thickness of soft layer. [ABSTRACT FROM AUTHOR]

Microphotoluminescence (μ-PL) investigation has been performed at room temperature on InAs quantum dot (QD) vertical cavity surface emitting laser (VCSEL) structure in order to characterize the QD epitaxial structure which was designed for 1.3 μm wave band emission. Actual and precise QD emission spectra including distinct ground state (GS) and excited state (ES) transition peaks are obtained by an edge-excitation and edge-emission (EEEE) μ-PL configuration. Conventional photoluminescence methods for QD-VCSELs structure analysis are compared and discussed, which indicate the EEEE μ-PL is a useful tool to determine the optical features of the QD active region in an as-grown VCSEL structure. Some experimental results have been compared with simulation results obtained with the aid of the plane-wave admittance method. After adjustment of epitaxial growth according to EEEE μ-PL measurement results, QD-VCSEL structure wafer with QD GS transition wavelength of 1300 nm and lasing wavelength of 1301 nm was obtained. [ABSTRACT FROM AUTHOR]

The hotspot and current self-heating effects on the spin-transfer-induced magnetization switching are investigated for low resistance magnetic tunnel junctions. Two kinds of spin torque theories, one for ohmic-like conduction from randomly distributed hotspots and the other for tunnel conduction from an insulator barrier, are combined together in this study by using a parallel resistor model. We find that the spin torque amplitude is locally enhanced in the hotspot region due to the large current density, which leads to a strong reduction of the current switching threshold (Jc), in a way that the enhanced spin torque induces the local magnetization near the hotspot switching first, and then drives the switching spreading through the whole free layer. The current self-heating effect is also studied; the free layer temperature increases only a few degrees at an applied current close to Jc∼1×107 A/cm2, which results in a slight decrease in Jc for the low resistance junctions with hotspots. [ABSTRACT FROM AUTHOR]

We have investigated the microstructures of melt-spun Sm(Co0.58Fe0.31Cu0.04Zr0.05B0.02)z (z=7.5 and 12) ribbons by transmission electron microscopy (TEM) and three dimensional atom probe (3DAP) to correlate them with the hard magnetic properties. The ribbon with z=7.5 has a high coercivity (iHc∼12 kOe) while the ribbon with z=12 possesses a low coercivity (iHc∼4.9 kOe). The high iHc ribbon comprises of nanocrystals (∼10 nm) having 1:7H (TbCu7) type structure as main phase. However, in the low iHc ribbon, the microstructure consists of both 1:7H and 2:17H (Th2Ni17) phases with crystal size ranging from 50 to 80 nm. The low coercivity ribbon also contains (CoFeZr)23B6 (M23B6 type) soft magnetic phase. The low coercivity obtained in the melt-spun ribbon with z=12 is due to: (i) the formation of Th2Ni17 type low anisotropy phase, (ii) the presence of boron-rich soft magnetic phase, and (iii) larger crystal size. Realization of high coercivity in the ribbon with z=7.5 is due to the formation of 1:7H, a high anisotropy phase, as well as reduced grain size. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Discusses the preparation of the anisotropic and isotropic Sm2Co17-type permanent magnets by using the conventional sintering technique. Characterization of the cellular structure within the Sm2(Fe,Co)17 grains; Application of the singular point detection technique on the anisotropic samples; Measurement of the saturation magnetization.

Presents a study that evaluated the effect of grain size and grain-size distribution on the intrinsic coercivity and the hysteresis loop of sintered iron-neodymium-boron magnets. Methodology; Influence of a bimodal grain size distribution on the hysteresis loop; Analysis of the scanning electron micrograph of the hard magnet.

Structure and magnetic properties of both melt-spun and hot deformed bulk Sm–Co type nanocomposite magnets have been investigated with various metal additions, including Zr, Cu, and Nb. The Zr and Nb additions play important roles in constraining grain growth, resulting in an increase of coercivity Hc. The Cu addition significantly improves the squareness of BH loops as well as the energy product (BH)max. A typical hot deformed bulk anisotropic nanocomposite SmCo type magnet with Mr(hard)/Mr(easy)∼0.4, Hc∼9 kOe and (BH)max of 13.2 MG Oe was obtained. [ABSTRACT FROM AUTHOR]

Melt-spun alloys of Pr3(Fe0.7Co0.3)27.5Ti1.5, Pr3(Fe0.6Co0.4)27.5Ti1.5, and Pr3(Fe0.5Ga0.1Co0.4)27.5Ti1.5 prepared at linear wheel speeds of 20, 30, and 40 m/s were found to contain nanocrystalline, a mixture of nanocrystalline and amorphous, and mostly amorphous phases, respectively. Grain sizes of <10 nm were observed for the crystalline phases. Annealed alloys showed an increase in grain size to 15–20 nm. The Curie temperature (TC) values observed in melt-spun alloys were lower than those observed in fully crystalline alloys. A reduction of ∼55 °C in TC was observed for the Pr3(Fe0.7Co0.3)27.5Ti1.5 composition compared to ∼15 °C for Pr3(Fe0.6Co0.4)27.5Ti1.5. For the Ga substituted alloy with Co=0.4, a large difference of ∼50 °C in TC was noted. MS values of 41 and 35 emu/g were observed in alloys with Co=0.4 and Ga=0.1, and Co=0.4, respectively, at room temperature. Ga substitution increased the anisotropy field value, HA, but lowered the intrinsic coercivity value, Hci. In the alloys with Co=0.4 and Ga=0.1, and Co=0.4, spin reorientation transitions (TSR) were observed at 220 and 140 K respectively. The low values of Hci observed in melt-spun ribbons are attributed to large amounts of a soft α-Fe phase. [ABSTRACT FROM AUTHOR]

Fully dense anisotropic nanocomposite Sm(Co0.58Fe0.31Zr0.05Cu0.04B0.02)z (z=7.5-12) magnets have been synthesized via rapid hot pressing and hot deformation processes. The highest (BH)max ∼10.6 MGOe was observed for a magnet with z=10. X-ray diffraction and M-H measurements indicated that the easy magnetization direction of magnets prefers to be in the hot pressing direction. Transmission electron microscopy investigation confirmed that plastic deformation is an important route for forming magnetic anisotropy in the Sm-Co-type nanocomposite magnets. Some stripe and/or platelike patterns have been observed inside the nanograins (50-200 nm), which may present as twins, and stacking faults. The (0001) twins have been observed in the 2:17R phase. [ABSTRACT FROM AUTHOR]

The magnetic properties of the ultrathin Fe/Co/Cu(100) films grown at 110 K with Co underlayer thickness below 2 monolayers (ML) are investigated by means of the in situ magneto-optical Kerr effect. The spin reorientation transitions (SRT) from out-of-plane to in-plane influenced by the Co underlayer are observed. A simplified bilayer growth mode of Co is introduced to fit the experiment results, obtaining that the true critical Fe thickness of a SRT if without structural transformation for a fct Fe on Cu(001) is about 4.6 ML, the same value as the previous Co capping experiment. [ABSTRACT FROM AUTHOR]

We determined the spin reorientation transition (SRT) in face-centered-tetragonal (fct) Fe/Cu(001) from out of plane to in plane, as induced by Ni-capping atoms, by observing the magneto-optical Kerr effect. The SRT takes place when the Ni-capping layer thickness exceeds a critical value d[sub c][sup Ni], at which point the perpendicular anisotropy of the fct-Fe film becomes equal to the in-plane anisotropy of the Ni-capping layer. We found that d[sub c][sup Ni] decreases linearly with increasing Fe film thickness. By extrapolating to zero Ni thickness, the “true” critical thickness for the fct-Fe films is estimated to be 4.3 monolayers. This result is very close to the value obtained using Co-capping layers as reported in literature. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Alloys with nominal compositions of Sm(Co[SUB1-x]Zr[SUBx])[SUBy] (x=0.03- 0.05, y=12- 15) were synthesized by arc melting and characterized in the temperature range of 10-1473 K and with a magnetic field up to 5 T. Near-single-phase materials with Th[SUB2]Ni[SUB17] structure were formed in the as-cast alloys with x = 0.05. Similar to Ti, Zr also stabilizes the Th[SUB2]Ni[SUB17] structure. Hard magnetic properties with T[SUBc]∼ 1142- 1179 K, M[SUBs] ∼ 110- 123 emu/g, and H[SUBa]∼ 63- 86 kOe at 300 K have been observed. An alloy with a nominal composition of Sm(Co[SUB0.75]Fe[SUB0.1]Zr[SUB0.05]Cu[SUB0.08]Ga[SUB0.01]B[SUB0.01])[SUB1 2] (as also prepared by melt spinning. The melt spun materials were nanostructured in nature and magnetically hard in the as-spun states. H[SUBci] ∼ 10 kOe, B[SUBs] ∼ 9.5 kG, and H[SUBci] ∼ 27 kOe, B[SUBs] ∼ 9.8 kG were obtained at 300 and 10 K, respectively. The effects of the heat treatment conditions on magnetic properties of both alloys and ribbon will be also discussed. [ABSTRACT FROM AUTHOR]

There has been continued technological and research interest in Nd[sub 2]Fe[sub 14]B-based compounds due to their excellent intrinsic magnetic properties [(BH)[sup *, sub max]∼64 MGOe,H[sub a]∼73 kOe]. It is found that Ti and Zr substitution in Nd[sub 2]Fe[sub l4]B leaves its magnetic properties largely unaffected. We have carried out neutron diffraction studies on Zr and Ti substituted 2:14:1 compounds. Three specimens of melt spun alloys of compositions (Nd[sub 0.75]Pr[sub 0.25])[sub 12]Fe[sub 80]B[sub 8], (Nd[sub 0.75]Pr[sub 0.25])[sub 8.4]Fe[sub 79.7]Ti[sub 4.7]B[sub 7.2] and (Nd[sub 0.75]Pr[sub 0.25])[sub 9.2]Fe[sub 79.2]Ti[sub 2]Zr[sub 2.2]B[sub 7.4] were studied. Rietveld refinements reveal that the 4f site is equally occupied by Nd and Pr while the 4g site is occupied only by Nd. In the Ti-containing sample, the lattice expands and Ti is found on the j[sub l], j[sub 2] sites normally occupied by Fe, (4% and 8%, respectively). This accounts for about 30% of the added Ti. In the third sample, the lattice contracts, which could occur only if Zr replaces the larger rare-earth atoms. However, due to the possibility of four different species occupying the 4f site (i.e., Nd, Pr, Ti, and Zr), it is not possible to determine their relative concentrations from neutron diffraction data alone. The balance of Ti and Zr in this sample must be locked in the grain boundaries. Despite peak broadening associated with the fine grain structure, robust refinements were achieved. [ABSTRACT FROM AUTHOR]

The magnetic properties and phase evolution of boron enriched Nd[sub χ]Fe[sub bal].TiCB[sub 10.5] (χ = 9, 9.5, 10, and 11) melt spun ribbons have been investigated. For χ = 9, 9.5, and 10, the main phases in the ribbons are Nd[sub 2]Fesub 14]B, Fe[sub 3]B, and a dilute α-Fe. For χ = 11, the Fe[sub 3]B phase is suppressed and only Nd[sub 2]Fe[sub 14]B and α-Fe were detected. An increase of rare earth content, from χ = 9 to χ = 10, was found to improve not only the intrinsic coercivity (iH[sub c]) but also the remanence (B[sub r]). The improvement in B[sub r] may be ascribed to the grain refinement as evidenced by transmission electron microscopy. A B [sub r] = 9.2 kG, [sub i]H[sub c] = 12.1 kOe, and (BH)[sub max] = 16.2 MGOe were obtained on Nd10Fe[sub bal].TiCB[sub 10.5] alloy ribbons quenched at 20 m/s followed with a 675 °C annealing for 10 min. Meanwhile, with an increase in the annealing temperature, the coercivity of the above alloy ribbons could be reduced to 9.8 kOe without sacrificing its B, and (BH)[sub max]. [ABSTRACT FROM AUTHOR]

The effect of Zr substitution for rare earth on the microstructure and hard magnetic properties of melt-spun composition of (Nd[sub 0.75]Pr[sub 0.25])[sub 12.5-χ]Zr[sub χ]Fe[sub 82]B[sub 5.5] (x = 0-3) has been investigated. It has been found that the coercivity decreases monotonically with the increasing Zr content, from 12.0 kOe at χ = 0 to 10.1 kOe with χ = 3. Unlike the coercivity, the remanence first increased with Zr substitution, from 8.65 up to 8.93 kG at χ = 2, and then decreased with further Zr substitution. The energy product behaved similarly, increasing from 15.7 MGOe to a maximum of 16.5 MGOe at χ = 2. X-ray diffraction (XRD), transmission electron microscope (TEM), and thermogravimetric analyzer studies have shown that all the samples were primarily composed of the single R[sub 2]Fe[sub 14]B phase. No additional phase was observed with Zr substitution. The lattice constants and the Curie temperature of the 2:14:1 phase were found to decrease monotonically with increasing Zr content, suggesting that all the Zr is situated into the 2:14:1 matrix, occupying the rare earth sites. TEM and XRD studies also revealed a significant grain size reduction with Zr substitution. The average grain size was reduced from approximately 40 nm in Zr-free samples to about 20 nm in samples with χ = 2. The observed change in magnetic properties with Zr substitution is explained by the grain size reduction. [ABSTRACT FROM AUTHOR]

Polycrystalline Ga-substituted Pr[sub 3](Fe[sub 1-x]Co[sub x])[sub 27.5]Ti[sub 1.5] (x=0.3,0.4) magnets have been studied for high temperature permanent magnets. Using x-ray diffraction, in addition to the majority 3:29 phase, the presence of the minority 2:17, 1:12 and α-Fe phases was observed. An increase in T[sub C] was observed with increasing Co content. A T[sub C] as high as 572 °C was observed for x=0.4. Magnetic measurements at room temperature showed an increase in the anisotropy field H[sub A] with increasing Co and Ga concentration, while the coercivity decreased. Scanning electron microscopy and energy dispersive x-ray analysis measurements indicated the 3:29 phase as the majority phase. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Alloys with the composition RCo[sub 7-x]Zr[sub x] (R=Y, Gd, Nd, or Ho, x=0–0.8) were synthesized and characterized in the temperature range from 10 to 1273 K and in fields up to 5 T. As with the R=Sm, Pr, or Er systems studied earlier in our laboratory, the effects of Zr doping on the stability of TbCu[sub 7] structure phase and changes in the magnetocrystalline anisotropy H[sub A] are observed in the systems in which the rare earth is Y, Gd, Nd, or Ho. Nearly single phase TbCu[sub 7] structure materials were formed in the as-cast alloys when x=0.1 and 0.2. In the case of R=Y or Gd, a large increase in H[sub A] (which is mainly contributed by Co sublattice) by Zr doping was observed. For R=Y, H[sub A] increases from 18 kOe for x=0 to 74 kOe for x=0.2 at 300 K and from 20 kOe for x=0 to 82 kOe for x=0.2 at 10 K. For R=Gd, H[sub A] increases from 35 kOe for x=0 to 140 kOe for x=0.2 at 300 K and to 182 kOe for x=0.2 at 10 K. In the case of R=Ho and Nd, the R-sublattice favors a planar anisotropy at room temperature, presumably due to the negative second order Stevens’ coefficient. For R=Ho, the anisotropy changes from planar for x=0 to axial with H[sub A]∼60–70 kOe at 300 K when x=0.1 and 0.2. For R=Nd, H[sub A] is dominated by R sublattice which results in a planar anisotropy. Other magnetic properties such as magnetization, Curie temperature, and spin reorientation temperature for these alloys are presented. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

An instrument used for measuring multiple scintillators' light output and energy resolution was developed. The instrument consisted of a light sensor array which was composed of 64 discrete SiPMs (Silicon Photomultipliers), a corresponding individual channel readout electronics system, and a data processing algorithm. A Teflon grid and a large interval between adjacent SiPMs were employed to eliminate the optical cross talk among scintillators. The scintillators' light output was obtained by comparing with a reference sample with known light output. Given the SiPM temperature dependency and the difference among each SiPM, a temperature offset correction algorithm and a non-uniformity correction algorithm were added to the instrument. A positioning algorithm, based on nine points, was designed to evaluate the performance of a scintillator array. Tests were performed to evaluate the instrument's performance. The uniformity of 64 channels for light output measurement was better than 98%, the stability was better than 98% when temperature varied from 15 °C to 40 °C, and the nonlinearity under 511 keV was better than 2%. This instrument was capable of selecting scintillators and evaluating the packaging technology of scintillator arrays with high efficiency and accuracy. [ABSTRACT FROM AUTHOR]

Discusses a study which stated that the combination of chemical composition and microstructure of cast alloy has been found to be critical to the performance of NdFeB sintered magnets. Reason for developing a two-step method; Result of the reduction in the amount of neodymium-rich grain boundary phase; Area in which NdFeB-type permanent magnets are used.

Investigates the effects of average grain size on the magnetic properties and corrosion resistance of neodymium-iron--boron sintered magnets. Details on the experiment; Relationships of the bulk corrosion rate and the magnetic properties of finished magnets; Optical micrography of magnets made from precursor alloy powders.

Presents a study that investigated the temperature-dependent magnetic properties of nine NdFeB sintered magnets with various cobalt (Co)-niobium, Co-vanadium, or Co-molybdenum additions which were measured up to 175°celsius using both closed-loop and open-circuit methods. Factors that affect the irreversible loss of induction; Details on the intrinsic coercivity; Discussion on magnet composition found to exhibit an outstanding thermal stability.

Presents information on a study which examined the spin-reorientation phenomena in rare earth alloys systems over a given temperature range using susceptibility measurement. Analysis of the rare earth alloy systems; Methodology of the study; Results and discussion.

Investigates microstructures of cast neodymium-iron-boron ingots. Cause of segregation of dendritic iron; Correlation of the magnetic properties of final magnets and the microstructures; Reason for the absence of dendritic iron.

Focuses on spin-reorientation phenomenon in praseodymium (Pr)-cobalt (Co) compound. Use of Hamiltonian consisting of the crystal-field term and exchange interaction; Result of the competition between the off-axial anisotropy of Pr sublattice and the axial anisotropy of Co sublattice; Magnetocrystalline superposition constants of the compound.

Presents a study which investigated the structural and magnetic properties of praseodymium[sub2]cobalt[sub7-x]iron[subx]boron[sub3]. Experimental details; Results and discussion; Conclusion.

Presents an overview of a study on the spin-reorientation transitions in pseudobinary compounds as determined by alternating current susceptibility measurements. Spin-orientation temperature; Causes of the decrease in temperature; Analysis of magnetic anisotropy phase diagrams.

Presents a study which examined the effect of crystal alignment on the remanence of sintered neodymium-iron-boron magnets. Comparison of remanence with the theoretical calculation based on the Stoner-Wohlfarth model; Experimental details; Results and discussion.

Presents information on a study which investigated the structural and magnetic properties of Nd[sub2]Co[7-x]Fe[subx]B[sub3] for x=0 to 7. Thermomagnetic analyses performed; Maintenance of the hexagonal symmetry; Illustration of the x-ray diffraction pattern of the compound.

Presents information on a study which examined the microstructure of conventionally case Sm(Co[subhal]Fe[sub0.28Cu[subv]Zr[sub0.022] alloys, by optical microscopy and scanning electron microscope with energy dispersed analytical x-ray in the as-cast state. Composition of the alloy series; Optical micrographs of cast ingots; Description of the samarium- and copper-rich grain boundary phase found in alloys.

Presents a study which fabricated Sm[sub2]Fe[sub17] nitride magnets with low melting point metal binders, zinc, tin or indium, using a powder metallurgical process. Materials and methods used; Results and discussion.

Presents a study which examined the microstructure and magnetic properties of yttrium titanium iron[sub11-x]cobalt[subx] and gadolinium titanium iron[sub11-x]cobalt[subx] systems. Experimental details; Results and discussion; Conclusion.

Presents a study that examined spin deterioration phenomenon in neodymium[sub0.5] erbium[sub1.5] iron[sub14-x] aluminum and cobalt[subx] boron as determined by alternating current susceptibility measurements. Details of the experiment; Results and discussion; Conclusion.

[Fe/Fe4N]N multilayers with high saturation magnetization were prepared on MgO(200) substrate, by the DC reactive magnetron sputtering and then annealed at higher temperature. Their structural and magnetic properties were investigated. Epitaxial growth of α-Fe and γ'-Fe4N were demonstrated on MgO, and then excellent [Fe/Fe4N]N was obtained. Though the saturation magnetizations of the as-deposited [Fe/Fe4N]N are slightly below the average value of those of α-Fe and γ'-Fe4N, the saturation magnetization of the annealed [Fe(3.04 nm)/Fe4N(3.04 nm)]5 increases up to 1850 emu/cc, 32 % larger than that of α-Fe film. N atom diffusion from the γ'-Fe4N to the α-Fe layer at high temperature greatly improves the saturation magnetization. [ABSTRACT FROM AUTHOR]

LECR4 (Lanzhou electron cyclotron resonance ion source No. 4) has been successfully constructed at IMP and has also been connected with the Low Energy Beam Transport (LEBT) and Radio Frequency Quadrupole (RFQ) systems. These source magnet coils are cooled through evaporative cooling technology, which is the first attempt with an ECR ion source in the world. The maximum mirror field is 2.5 T (with iron plug) and the effective plasma chamber volume is 1.2 l. It was designed to be operated at 18 GHz and aimed to produce intense multiple charge state heavy ion beams for the linear injector project SSC-Linac at IMP. In February 2014, the first analyzed beam at 18 GHz was extracted. During about three months' commissioning, some outstanding results have been achieved, such as 1.97 emA of O6+, 1.7 emA of Ar8+, 1.07 emA of Ar9+, and 118 euA of Bi28+. The source has also successfully delivered O5+ and Ar8+ ion beams for RFQ commissioning in April 2014. This paper will give a brief overview of the design of LECR4. Then, the latest results of this source at 18 GHz will be presented. [ABSTRACT FROM AUTHOR]

The interlayer exchange coupling properties in synthetic antiferromagnetic (AF) structures based on Co/Ni perpendicular multilayers were investigated by varying the Ru spacer thickness (tRu) and the ferromagnetic (FM) layer material at the FM/Ru interfaces. Samples of two Co layers adjacent to Ru own much stronger AF coupling field (HAF) and show two HAF peaks located at tRu = 0.47 and 1.08 nm. If the interfacial Co layers are substituted by Ni, the HAF at the 1st peak decreases much more considerably, becomes lower than the 2nd one and even disappears due to strong pinhole-induced FM coupling. Such pinhole effect makes HAF of tRu < 0.85 nm remains unchanged or even decrease with decreasing temperatures. By tuning the interfacial Co layer thickness, pinhole effect has been suppressed as a result of greatly enhanced HAF, leading to a normal temperature dependence of Ruderman-Kittel-Kasuya-Yosida-type HAF even at thin tRu cases, i.e., increase in HAF with temperature decreasing. [ABSTRACT FROM AUTHOR]

In this study, an exchange coupled composite (ECC) film with an antiferromagnetic sandwich structure L10-FePt/[Co/Ni]5/Ru/[Co/Ni]10 (FePt-CN-Ru) is prepared via dc magnetron sputtering and measured by vibrating sample magnetometer. The results show that FePt-CN-Ru film exhibits ECC characteristics, with excellent angular tolerance, low remanance magnetization, and a narrow switching field. Its thermal stability is higher than that of conventional ECC film. Finally, magnetization reversal is demonstrated through micromagnetic simulation. [ABSTRACT FROM AUTHOR]

A negative hydrogen (H-) ion source with hot cathode arc discharge was designed and fabricated as a primary injector for a 10 MeV PET cyclotron at IMP. 1 mA dc H- beam with ε N RMS = 0.08 ж mm mrad was extracted at 25 kV. Halbach hexapole was adopted to confine the plasma. The state of arc discharge, the parameters including filament current, arc current, gas pressure, plasma electrode bias, and the ratio of ... were experimentally studied. The discussion on the result, and opinions to improve the source were given. [ABSTRACT FROM AUTHOR]

The perpendicular magnetic properties of glass/Ta/Cu/[Co/Ni]4/Ta multilayers can be efficiently tuned by in situ pre-annealing the Ta/Cu under-layers at various temperatures (TCu) before the deposition of the Co/Ni stack. As a result of the co-effect of fcc(111) texture and Cu surface roughness, the perpendicular anisotropy Ku and coercivity Hc⊥ exhibit a similar non-monotonous dependence on the TCu, showing minimum values at TCu = 100 °C and maxima at 400 °C for Ku while at 550 °C for Hc⊥. By in situ annealing the under-layers at 550 °C and then post-annealing the whole stack at 250 °C, the Hc⊥ value can be significantly enhanced from 139 Oe up to 620 Oe, which is important for spintronic applications. [ABSTRACT FROM AUTHOR]

Two series of exchange coupled composite films with and without Ag interlayer, L10-[FePt-Ag]/[Co/Ni]N (FC-Ag-N) and FePt/[Co/Ni]N (FC-N), were prepared and well studied. Coercivities of both series decrease with the increase of the soft [Co/Ni]N thickness. However, well-isolated sphere grains are observed in FC-Ag-N samples, instead of a ledge-type structure in FC-N samples. The average grain size is almost constant for FC-Ag-N films, regardless of the thickness of Co/Ni multilayer. It indicates that Ag effectively suppresses the grain coarseness during the deposition of [Co/Ni]N. [ABSTRACT FROM AUTHOR]

The mechanism of depinning process of vortex domain wall (DW) in a planar magnetic nanowire with an asymmetric notch is investigated by using focused magneto-optical Kerr effect (MOKE) magnetometer and micromagnetic modeling. Two distinct depinning fields are directly observed by the single-shot MOKE measurements. Micromagnetic modeling provides physical insight into the details of how the depinning process develops at the asymmetric notch and reveals that the different depinning fields originate from the different chiralities of the vortex DWs. [ABSTRACT FROM AUTHOR]

Superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL) is an all-superconducting-magnet electron cyclotron resonance ion source (ECRIS) for the production of intense highly charged ion beams to meet the requirements of the Heavy Ion Research Facility in Lanzhou (HIRFL). To further enhance the performance of SECRAL, an aluminum chamber has been installed inside a 1.5 mm thick Ta liner used for the reduction of x-ray irradiation at the high voltage insulator. With double-frequency (18+14.5 GHz) heating and at maximum total microwave power of 2.0 kW, SECRAL has successfully produced quite a few very highly charged Xe ion beams, such as 10 e μA of Xe37+, 1 e μA of Xe43+, and 0.16 e μA of Ne-like Xe44+. To further explore the capability of the SECRAL in the production of highly charged heavy metal ion beams, a first test run on bismuth has been carried out recently. The main goal is to produce an intense Bi31+ beam for HIRFL accelerator and to have a feel how well the SECRAL can do in the production of very highly charged Bi beams. During the test, though at microwave power less than 3 kW, more than 150 e μA of Bi31+, 22 e μA of Bi41+, and 1.5 e μA of Bi50+ have been produced. All of these results have again demonstrated the great capability of the SECRAL source. This article will present the detailed results and brief discussions to the production of highly charged ion beams with SECRAL. [ABSTRACT FROM AUTHOR]

Superconducting electron cyclotron resonance ion source with advance design in Lanzhou (SECRAL) is an 18–28 GHz fully superconducting electron cyclotron resonance (ECR) ion source dedicated for highly charged heavy ion beam production. SECRAL, with an innovative superconducting magnet structure of solenoid-inside-sextupole and at lower frequency and lower rf power operation, may open a new way for developing compact and reliable high performance superconducting ECR ion source. One of the recent highlights achieved at SECRAL is that some new record beam currents for very high charge states were produced by 18 GHz or 18+14.5 GHz double frequency heating, such as 1 e μA of 129Xe43+, 22 e μA of 209Bi41+, and 1.5 e μA of 209Bi50+. To further enhance the performance of SECRAL, a 24 GHz/7 kW gyrotron microwave generator was installed and SECRAL was tested at 24 GHz. Some promising and exciting results at 24 GHz with new record highly charged ion beam intensities were produced, such as 455 e μA of 129Xe27+ and 152 e μA of 129Xe30+, although the commissioning time was limited within 3–4 weeks and rf power only 3–4 kW. Bremsstrahlung measurements at 24 GHz show that x-ray is much stronger with higher rf frequency, higher rf power. and higher minimum mirror magnetic field (minimum B). Preliminary emittance measurements indicate that SECRAL emittance at 24 GHz is slightly higher that at 18 GHz. SECRAL has been put into routine operation at 18 GHz for heavy ion research facility in Lanzhou (HIRFL) accelerator complex since May 2007. The total operation beam time from SECRAL for HIRFL accelerator has been more than 2000 h, and 129Xe27+, 78Kr19+, 209Bi31+, and 58Ni19+ beams were delivered. All of these new developments, the latest results, and long-term operation for the accelerator have again demonstrated that SECRAL is one of the best in the performance of ECR ion source for highly charged heavy ion beam production. Finally the future development of SECRAL will be presented. [ABSTRACT FROM AUTHOR]

LECR4 (Lanzhou ECR ion source No. 4) is a room temperature electron cyclotron resonance ion source, designed to produce high current, high charge state ion beams for the SSC-LINAC injector (a new injector for sector separated cyclotron) at the Institute of Modern Physics. LECR4 also serves as a PoP machine for the application of evaporative cooling technology in accelerator field. To achieve those goals, LECR4 ECR ion source has been optimized for the operation at 18 GHz. During 2014, LECR4 ion source was commissioned at 18 GHz microwave of 1.6 kW. To further study the influence of injection stage to the production of medium and high charge state ion beams, in March 2015, the injection stage with pumping system was installed, and some optimum results were produced, such as 560 eμA of O7+, 620 eμA of Ar11+, 430 eμA of Ar12+, 430 eμA of Xe20+, and so on. The comparison will be discussed in the paper. [ABSTRACT FROM AUTHOR]

To satisfy the requirements of surface and atomic physics study in the field of low energy multiple charge state ion incident experiments, a low energy (10 eV/q–20 keV/q) ion beam platform is under design at IMP. A simple test bench has been set up to test the ion beam deceleration systems. Considering virtues such as structure simplicity, easy handling, compactness, cost saving, etc., an all-permanent magnet ECRIS LAPECR1 [Lanzhou all-permanent magnet electron cyclotron resonance (ECR) ion source No. 1] working at 14.5 GHz has been adopted to produce intense medium and low charge state ion beams. LAPECR1 source has already been ignited. Some intense low charge state ion beams have been produced on it, but the first test also reveals that many problems are existing on the ion beam transmission line. The ion beam transmission mismatches result in the depressed performance of LAPECR1, which will be discussed in this paper. To obtain ultralow energy ion beam, after being analyzed by a double-focusing analyzer magnet, the selected ion beam will be further decelerated by two afocal deceleration lens systems, which is still under design. This design has taken into consideration both ions slowing down and also ion beam focusing. In this paper, the conceptual design of deceleration system will be discussed. [ABSTRACT FROM AUTHOR]