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The results of luminescence measurements in magnetic fields up to 23T of strain free GaN bulk crystals doped with gadolinium are presented. The magnetic field splitting pattern observed for the Gd-related transitions in the "red" spectral range is consistent with its identification as due to intracenter transitions between Gd³⁺ ion levels. The Gd-related emission structures observed close to the GaN bandgap show magnetic field behavior which could be understood in terms bound exciton or donor-acceptor pair recombination involving Gd ions. Disappointingly, no giant Zeeman splitting, which otherwise could confirm ferromagnetism in this material, was observed.

Single phase polycrystalline Gd_1-xPr_xBa₂Cu₃O_7-δ (0 ≤ x ≤ 0.10) samples have been prepared by standard solid state reaction technique and characterized by SEM, X-ray diffraction and electrical transport experiments. The samples were granular and homogeneous. It was observed that the critical temperature decreases and that the transition width increases with increasing Pr doping. Systematic measurements of fluctuation conductivity are reported. Special attention is taken above the critical temperature, where Gaussian and critical regimes are observed. Below the critical temperature, on approaching the zero resistance state, our results show a power-law behavior consistent with a phase transition from a paracoherent to a coherent state of the granular array.

Gadolinium (Gd) ion implantation with doses from 2.5 × 10¹⁶ to 1 × 10¹⁷ ions/cm² into ZK60 magnesium alloy was carried out to improve its surface properties. X-ray photoelectron spectroscopy (XPS), nanoindenter, electrochemical workstation and scanning electron microscope (SEM) were applied to analyze the chemical composition, nanomechanical properties and corrosion characteristics of the implanted layer. The results indicate that Gd ion implantation produces a hybrid-structure protective layer composed of MgO, Gd₂O₃ and metallic Gd in ZK60 magnesium alloy. The surface hardness and modulus of the Gd implanted magnesium alloy are improved by about 300% and 100%, respectively with the dose of 1 × 10¹⁷ ions/cm², while the slowest corrosion rate of the magnesium alloy in 3.5 wt.% NaCl solution is obtained with the dose of 5 × 10¹⁶ ions/cm².

Rare earth metals, when deposited and oxidized on semiconductor surfaces, can be an alternative to unstable compounds of alkali metals while creating stable and effective emitters with a low work function. A procedure giving rise to the adsorption of Gd and O atoms on the Si(100) surface and the formation of a Si–Gd–O film with a work function of about 1 eV in the near-surface region is described. The films have been studied using the Auger electron and photoelectron spectroscopy, as well as X-ray diffraction, atomic force and Kelvin probe force microscopy techniques. Information about their electronic properties, structure, surface morphology, and surface distribution of potential was obtained. The main component of the film formed on the Si surface is a polycrystalline Gd₂O₃ phase, which plays the role of a matrix containing textured microcrystallites of one of the following phases: SiO₂, GdO₂, or GdSi₂. The film surface consists of salient clusters 20nm to 80nm in diameter and up to 20nm in height, as well as craters up to 90nm in depth. The surface relief inhomogeneities correlate with the surface distribution of the local work function. This correlation can also be a result of the piezoelectric effect in the strained crystallites of the textured phase located in the bulk of the film. The obtained system was stable in time under vacuum conditions and heating up to $600^{\circ }$C. The method proposed for the formation of surfaces with a low work function making use of rare earth metals can be applied to create effective and stable electron emitters.

Characteristic emission from gadolinium-doped amorphous aluminum nitride thin films deposited on Si(111) substrate are studied, with cathodoluminescence and photoluminescence, for their suitability as tissue compensators in radiation treatment planning. These films are deposited by reactive sputtering at liquid nitrogen temperature, using 100–200 W rf power, 5–8 mTorr nitrogen, and a metal target of aluminum and gadolinium. Thermal annealing was performed at a temperature of 900°C. A sharp ultraviolet peak is observed at 314 nm, corresponding to ⁶P_7/2 → ⁸S_7/2 transition. The ultraviolet emission is intense enough to harm human tissues if it is used as a tissue compensator. Thermal annealing further enhances the intensity of ultraviolet emission, indicating that its longer use as tissue compensator will provide more harm and damage to the human body.

Synthesis of two bimodal imaging agents consist of a hydrophobic zinc(II) tetrapentafluorophenylporpholactol core and a β-substituted hydrophilic Gd(III) DO3A (ZnLGd₅₃₉) or DOTA (ZnLGd₅₉₅) like moiety has been described (DO3A = 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid, DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid). Through β-conjugation approach, the absorption at deep red region increases compared to traditional conjugation methods at meso-position. More importantly, these new complexes possess largely improved ionic relaxitivites relative to the sole Gd(III) magnetic resonance imaging (MRI) agents such as Gd(III) DO3A and Gd(III) DOTA like complexes. Combining the optical and magnetic resonance measurements in aqueous media, the largely enhanced r₁ relaxivities was attributed to the aggregation of ZnLGd₅₃₉ and ZnLGd₅₉₅ in aqueous media. Furthermore, fluorescence and magnetic resonance imaging experiment showed that both ZnLGd₅₃₉ and ZnLGd₅₉₅ can be applied as potential bimodal imaging contrast agents. Finally, both compounds showed no dark cytotoxicity and good photocytotoxicity (IC₅₀ = 1.73 ± 0.13 and 1.52 ± 0.10 μM for ZnLGd₅₃₉ and ZnLGd₅₉₅ respectively) on Hela cells.

Functional imaging is a novel area in radiological sciences and allows for the non-invasive assessment and visualization of specific targets such as gene and protein expression, metabolic rates, and drug delivery in intact living subjects. As such, the field of molecular imaging has been defined as the non-invasive, quantitative, and repetitive imaging of biomolecules and biological processes in living organisms. For example, cancer cells may be genetically altered to attract molecules that alter the magnetic susceptibility, thereby permitting their identification by magnetic resonance imaging. These contrast agents and/or molecular reporters are seen as essential to the task of molecular medicine to increase both sensitivity and specificity of imaging. Therefore, there are five general principles which need to be fulfilled in order to conduct a successful in vivo molecular imaging study: (1) selection of appropriate cellular and subcellular targets; (2) development of suitable in vivo affinity ligands (molecular probes); (3) delivery of these probes to the target organ; (4) amplification strategies able to detect minimal target concentrations; and (5) development of imaging systems with high resolution. Although there has been a wide range of routes taken to incorporate both imaging agents and a disease-targeting moiety into diagnostic devices, arguably the most interesting of these routes employs the use of nanoparticles. Nanoscale diagnostic systems that incorporate molecular targeting agents and diagnostic imaging capabilities are emerging as the next-generation imaging agents and have the potential to dramatically improve the outcome of the imaging, diagnosis, and treatment of a wide range of diseases. The present review addresses chemical aspects in development of molecular probes based upon gadolinium nanoparticles and their potential role in translational clinical imaging and therapy.

This paper describes a prototype of a linear reciprocating magnetic refrigerator using a gadolinium parallel plate. The new design of the regenerator, installation, and experiment is presented. The regenerator consists of a gadolinium plate and an inlet/outlet section. The thickness and length of the gadolinium plate are 1mm and 80mm, respectively. The gap between parallel plates is 0.1mm. Water is used as the heat transfer fluid. The permanent magnet structure used in the present study can generate a maximum magnetic field intensity of 0.94 T. The effects of surface roughness of the gadolinium parallel plate on the temperature span and cooling capacity are investigated. The results show that there is no significant effect of surface roughness on the magnetic refrigerator performance at a high utilization factor. The results from the present study are important for the design of magnetic refrigerators operating at room temperature.

Magnetic refrigeration is an environment-friendly cooling technology and an interesting potential replacement for the vapor compression refrigeration system. This paper presents a linear reciprocating magnetic refrigerator prototype that operates at room temperature by using gadolinium parallel plates under a maximum magnetic field intensity of 0.94T. The design, installation and preliminary results are reported. The temperature span and cooling capacity are studied in a function of cycle frequency, and the results show the cycle frequency effects on temperature span and cooling capacity. The maximum temperature span and cooling capacity for cycle frequency of 0.16Hz are 1.3K and 4.68W, respectively. The results from the experiment will be a guideline to determine the maximum performance of the magnetic refrigerator prototype.

Europe monitors transits using radiation detectors to prevent illicit trafficking of nuclear materials. The SCINTILLA project aims to develop a toolbox of innovative technologies designed to address different usage cases. This article will review the scope, approach, results of the first benchmark campaign and future plans of the SCINTILLA project.