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Understanding the nature, density, and distribution of structural defects is crucial for tailoring the properties of atomically thin two‐dimensional (2D) materials, which is paramount for advances in nanotechnology. Ion irradiation emerges as a promising technique for defect engineering of single‐atom‐thick materials, due to its high controllability, repeatability, and accuracy. The objective is to provide a comprehensive review elucidating the impact of various irradiation parameters, such as ion mass, energy, fluence, and incident angle, on defect formation in 2D materials. However, the presence of the substrate can significantly influence defect yield and the mechanism of formation due to backscattered ions and sputtered substrate atoms. Hence, a thorough comparison of ion beam‐induced defects in both freestanding (suspended) and supported (on a substrate) 2D materials, with a focus on substrate effects is conducted. Moreover, a detailed analysis of characterization techniques suitable for each scenario will be provided. This work not only contributes to advancing the current understanding of defect formation and evolution in 2D materials during ion beam irradiation but also offers insights into selecting specific parameters for this process to create desired defects in these materials. Consequently, it has the potential to facilitate the design of nanoscale devices with tailored functionality. [ABSTRACT FROM AUTHOR]

In-depth statistics of individual defects observed during transmission electron microscopy (TEM) experiments are essential for the thorough characterization of materials. In this study, we aim to quantitatively characterize the population of dislocation loops in ion-irradiated CrFeMnNi alloys. To this end, we propose an efficient guideline to prepare TEM micrographs dataset for deep learning analysis, adapted for accurate characterization of microstructures produced by thousands of overlapping defects, a very common situation in TEM images, unfeasible by previous existing methods. To reduce human effort, we annotate only a few images and complement the database through a two-step process: initially, singular value decomposition to normalize image background, followed by a controlled data augmentation. The performed analysis provides precise quantitative information about the number of loops of different types, as well as their spatial distribution, their size, and the inter-object distances. These characteristics provide insights into the nucleation, mobility, and growth of dislocation loops, as well as the elastic anisotropy of the material. Our results emphasize how accurate analysis of complex microstructures can provide insights into the physical properties of materials and open up many perspectives for attaining quantitative information on materials properties based solely on their image analysis. [ABSTRACT FROM AUTHOR]

This report demonstrates tunable carrier densities in CdO thin films through local ion irradiation, providing lateral control of mid‐IR optical properties. Ion‐solid interactions produce donor‐like defects that boost electron concentrations from the practical minimum of 2.5 × 1019 cm−3 to a maximum of 2.5 × 1020 cm−3 by metered ion exposure. This range is achieved using He, N, Ar, or Au ions at 1–2.8 MeV; when normalized by displacements per atom, all ion species produce comparable results. Since CdO is well‐described by the Drude model, irradiation‐tuned carrier densities directly alter the infrared dielectric function, and in turn, mid‐infrared optical properties. Further, it is demonstrated that by combining irradiation with traditional lithography, CdO films expose to ions in the presence of 3‐µm thick, patterned photoresist exhibit lateral carrier density profiles with ≈400‐nm resolution. Scanning near‐field optical microscopy reveals sharp optical interfaces with almost no companion contrast in surface morphology, microstructure, or crystallinity. Finally, CdO lateral homostructures supporting surface plasmon polaritons (SPPs) are demonstrated whose dispersion relation can be tuned through periodic patterning in a monolithic platform by simple nanofabrication. Numerical simulations show these polaritons result from strong coupling between excitations at CdO plasma frequencies and SPPs supported by the platinum substrate. [ABSTRACT FROM AUTHOR]

A new type of SiCf/TiC-Ti3SiC2 composite was prepared by the Spark Plasma Sintering (SPS) method in this work. The phase transformation and interface cracking of this composite under ion irradiation (single Xe, Xe + He, and Xe + He + H ions) and subsequent annealing were analyzed using transmission electron microscopy (TEM), mainly focusing on the interface regions. Xe ion irradiation resulted in the formation of high-density stacking faults in the TiC coatings and the complete amorphization of SiC fibers. The implanted H ions exacerbated interface coarsening. After annealing at 900 °C for 2 h, the interface in the Xe + He + H ion-irradiated samples was seriously damaged, resulting in the formation of large bubbles and cracks. This damage occurred because the H atoms reduced the surface free energy, thereby promoting the nucleation and growth of bubbles. Due to the absorption effect of the SiCf/TiC interface on defects, the SiC fiber areas near the interface recovered back to the initial nano-polycrystalline structure after annealing. [ABSTRACT FROM AUTHOR]

Memristors‐based neuromorphic devices represent emerging computing architectures to perform complex tasks by outpacing the traditional Von‐Neumann architectures in terms of speed, and energy efficiency. In this work, the resistive switching (RS) behavior of sol‐gel grown and ion‐irradiated BFO films is investigated under electrical stimulus. The Ag/BFO/FTO memristors emulate a combination of digital and analog RS behavior within a single device. The possible mechanism of analog digital hybridity is addressed by considering the formation of the conducting filament by oxygen vacancies, Ag+ ions and Schottky barrier height modulation. The ion‐irradiated BFO samples are analyzed using the Raman, XRD, and XPS studies. To uphold bioinspired synaptic actions, crucial synaptic functionalities like pair‐pulse facilitation and long‐term potentiation/depression are effectively achieved. More intricate synaptic behaviors are also demonstrated such as spike‐time‐dependent plasticity and Pavlovian classical conditioning, which represent the prominent attributes of both learning and forgetting behavior. Additionally, high pattern recognition accuracy (96.1%) is achieved in an artificial neural network simulation by using the synaptic weights of the memristors. This synergistic effect of digital and analog RS in ion‐irradiated BFO can be beneficial for the emulation of complex learning behavior as well as its incorporation into low‐power neuromorphic computing. [ABSTRACT FROM AUTHOR]

In the present communication, structural and electrical properties of Y0.95Ca0.05MnO3 (YCMO) manganite thin films, having different thicknesses grown on (100) single crystalline Nb:SrTiO3 (SNTO) substrate using pulsed laser deposition (PLD) technique, have been investigated. Influence of 100 MeV O+7 energetic ion irradiation has been understood on the basis of structure–property correlations across the lattice of YCMO manganite. Influence of YCMO film thickness and ion fluence on the electrical properties have also been explored in the context of lattice strain, crystallite size (CS), crystallinity, defect state, local annealing effect and three dimensional disorder. YCMO/SNTO interface experiences the presence of tensile strain which is found to vary between +1.02 and +1.88% for 100 nm YCMO/SNTO thin film whereas it is found to decrease monotonically from +1.50 to +0.98% for 200 nm and +1.40 to +0.92% for 300 nm upon increase in ion fluence. For higher thicknesses of YCMO/SNTO films (i.e. 200 and 300 nm), CS (estimated using Scherrer's formula) is found to increase from 19.73 nm for pristine to 25.01 nm for higher influence irradiated 200 nm film and from 24.91 nm for pristine to 27.97 nm for higher influence irradiated 300 nm film which has been ascribed to the local annealing effect across the YCMO/SNTO thin film lattices. Variation in dielectric constant with frequency, YCMO layer thickness and ion fluence has been understood on the bases of lattice strain, defect state, CS, crystallite boundaries, dipolar relaxation and universal dielectric response (UDR) model. Nature of ac conductivity has been understood well in the context of Jonscher's power law fits where correlated barrier hopping (CBH) mechanism has been confirmed as a responsible process for charge conduction across the YCMO/SNTO interfaces. Maximum barrier height (Wm) has been derived using its relation with power exponent from Jonscher's power law fits to ac conductivity data and its values are found to vary nonmonotonically between 0.3218 and 0.4849 eV for 100 nm YCMO/SNTO film however it gets enhanced from 0.2382 to 0.3820 eV for 200 nm and from 0.1977 to 0.2203 eV for 300 nm YCMO/SNTO films upon increase in oxygen ion fluence. These variations have been ascribed to the dominant impact of high resistive insulating nature of core of the YCMO crystallites and three dimensional disorder across YCMO manganite lattice. Present report serves a complex simultaneous impact of YCMO layer thickness, ion fluence and related structural aspects on the electrical properties of YCMO/SNTO films where defect state can be regenerated through well established experimental tool of SHI irradiation in a controlled way. The electric properties of YCMO/SNTO thin films are of paramount importance in a variety of technological applications and are of fundamental importance for materials science research. [ABSTRACT FROM AUTHOR]

Large-grained UO2 is considered a potential accident-tolerant fuel (ATF) due to its superior fission gas retention capabilities. Irradiation experiments for cerium dioxide (CeO2), used as a surrogate fuel, is a common approach for evaluating the performance of UO2. In this work, spark plasma sintered CeO2 pellets with varying grain sizes (145 nm, 353 nm, and 101 μm) and a relative density greater than 93.83% were irradiated with 4 MeV Xe ions at a fluence of 2 × 1015 ions/cm2 at room temperature, followed by annealing at 600 °C for 3 h. Microstructure, including dislocation loops and bubble morphology of the irradiated samples, has been characterized. The average size of dislocation loops increases with increasing grain size. Large-sized dislocation loops are absent near the grain boundary because the boundary absorbs surrounding defects and prevents the dislocation loops from coalescing and expanding. The distribution of bubbles within the grain is uniform, whereas the large-sized and irregularly shaped xenon bubbles observed in the small grain exhibit pipe diffusion along the grain boundaries. The bubble diameter in the large-grained pellet is the smallest. As the grain size increases, the volumetric swelling of the irradiated pellets decreases while the areal density of Xe bubbles increases. Elemental segregation, which tends to occur at dislocation loops and grain boundaries, has been analyzed. Large-grained CeO2 pellet with lower-density grain boundaries exhibits better resistance to volumetric swelling and elemental segregation, suggesting that large-grained UO2 pellets could serve as a potential ATF. [ABSTRACT FROM AUTHOR]

The paper presents the results of studying the structure and phase state of tungsten and tungsten-copper alloy after pulsed action of compression plasma flows and irradiation with helium ions. The compression plasma flows were used to modify the surface layer of tungsten, as well as to create an alloy based on tungsten and copper. Using scanning electron microscopy and X-ray structural analysis, the formation of radiation defects on the tungsten surface was detected in the form of local areas of exfoliation and destruction, which begin to form at helium ion irradiation doses of 2 × 1017 cm−2. It is shown that preliminary plasma treatment of the surface in the melting mode leads to the complete disappearance of surface radiation defects up to a dose of 2 × 1017 cm−2, which may be associated with the formation of a fine-crystalline grain structure, the intergranular boundaries of which serve as effective sinks for primary radiation defects. [ABSTRACT FROM AUTHOR]

An accurate description of short-range interactions among atoms is crucial for simulating irradiation effects in applications related to ion modification techniques. A smooth integration of the Ziegler–Biersack–Littmark (ZBL) potential with the adaptive intermolecular reactive empirical bond-order (AIREBO) potential was achieved to accurately describe the short-range interactions for carbon-based materials. The influence of the ZBL connection on potential energy, force, and various AIREBO components, including reactive empirical bond-order (REBO), Lennard–Jones (LJ), and the torsional component, was examined with configurations of the dimer structure, tetrahedron structure, and monolayer graphene. The REBO component is primarily responsible for the repulsive force, while the LJ component is mainly active in long-range interactions. It is shown that under certain conditions, the torsional energy can lead to a strong repulsive force at short range. Molecular dynamics simulations were performed to study the collision process in configurations of the C-C dimer and bulk graphite. Cascade collisions in graphite with kinetic energies of 1 keV and 10 keV for primary knock-on atoms showed that the short-range description can greatly impact the number of generated defects and their morphology. [ABSTRACT FROM AUTHOR]

The effects of 1.75 MeV N5+ ion beam irradiation of varying ion fluences, ranging from 1 × 1012 to 3 × 1014 ions/cm2, on high-density polyethylene have been done to investigate the structural, optical and chemical properties using X-ray diffraction (XRD), UV–visible spectroscopy and Fourier transform infrared (FTIR) spectroscopic techniques. XRD patterns show no significant change in crystallinity in irradiated polymer samples. The lattice plane and crystallite size of the irradiated polymer have not changed noticeably. More than 50% decrease in optical band gap were found for higher ion fluences of 3 × 1014 ions/cm2. UV–visible spectra show a red shift in absorption maxima due to the formation of extended conjugation. FTIR peaks 3646, 1707 and 2170 cm−1 in irradiated polymer were observed. The reaction mechanism chemistry of radiation-induced product formations, including chain scission, molecular crosslinking and hydroxyl, carbonyl and alkyne functional groups have been discussed. [ABSTRACT FROM AUTHOR]

Thin films of yttria-stabilized zirconia (YSZ) were synthesized using spin coating technique on glass substrates with various concentration of yttria. The films were irradiated with Li3+ ions of energy 50 MeV and fluence values of 1 × 1011, 5 × 1012 and 5 × 1013 ions/cm2. The results obtained for the irradiated films are compared with the pristine sample. X-ray diffraction (XRD) was employed to confirm the structural phase and investigate the variation in crystallinity of irradiated thin films. X-ray diffraction analysis confirmed that the higher yttria concentrations corresponded to decrease in crystallinity in the zirconia, corroborated by calculated crystallite sizes. Interestingly, no phase formation was observed in sample YSZ (8%), highlighting the necessity of elevated annealing temperatures for phase formation, particularly at higher yttria concentrations. Significantly, the structural information was validated through Raman spectroscopy which revealed the decrease in the monoclinic phase with increasing yttria doping. The optical band gap of Zirconia increased with higher yttria doping concentration, resulting in a range of band gap from 4.11 eV to 4.15 eV. The exposure of YSZ thin films to Li3+ ions with an energy of 50 MeV unveiled impacts of ion fluence. Lower fluence levels resulted in observable damage to crystallinity when contrasted with pristine YSZ samples, as manifested by the broadening of diffraction peaks. At moderate fluence levels, a decrease in crystallinity damage was noted, nonetheless, at higher fluence levels, the damage intensified once more. The ion irradiation of YSZ (8%) resulted in the emergence and growth of crystalline phases. [ABSTRACT FROM AUTHOR]

This study explores defect engineering in 2D materials using ion beam irradiation to modify the electrical and optical properties with potential in advancing quantum electronics and photonics. Helium and neon ions ranging from 5 to 7.5 keV are employed to manipulate charge transport in monolayer molybdenum disulfide (MoS2). In situ electrical characterization occurs without vacuum breakage post‐irradiation. Raman and photoluminescence spectroscopy quantify ion irradiation's impact on MoS2. Small doses of helium ion irradiation enhance monolayer MoS2 conductivity in field‐effect transistor geometry by inducing doping and substrate charging. Findings reveal a strong correlation between the electrical properties of MoS2 and the primary ion used, as well as the substrate on which the irradiation occurred. Using hexagonal boron nitride (h‐BN) as a buffer layer between MoS2 flake and SiO2 substrate yields distinct alterations in electrical behavior subsequent to ion irradiation compared to the MoS2 layer directly interfacing with SiO2. Molecular dynamics simulations and density functional theory provide insight into experimental results, emphasizing substrate influence on measured electrical properties post‐ion irradiation. [ABSTRACT FROM AUTHOR]

Abstract In-depth statistics of individual defects observed during transmission electron microscopy (TEM) experiments are essential for the thorough characterization of materials. In this study, we aim to quantitatively characterize the population of dislocation loops in ion-irradiated CrFeMnNi alloys. To this end, we propose an efficient guideline to prepare TEM micrographs dataset for deep learning analysis, adapted for accurate characterization of microstructures produced by thousands of overlapping defects, a very common situation in TEM images, unfeasible by previous existing methods. To reduce human effort, we annotate only a few images and complement the database through a two-step process: initially, singular value decomposition to normalize image background, followed by a controlled data augmentation. The performed analysis provides precise quantitative information about the number of loops of different types, as well as their spatial distribution, their size, and the inter-object distances. These characteristics provide insights into the nucleation, mobility, and growth of dislocation loops, as well as the elastic anisotropy of the material. Our results emphasize how accurate analysis of complex microstructures can provide insights into the physical properties of materials and open up many perspectives for attaining quantitative information on materials properties based solely on their image analysis.

The swelling behavior of ferritic/martensitic steels (FC92–B/-N, HT9, and Gr.92) was investigated following 3.5 MeV Fe++ ion irradiation. Tested alloys were helium-pre-implanted up to the peak contents of 120 and 240 appm with He/dpa ratio of 1 appm/dpa at room temperature and then exposed to self-ion beam to the peak damage conditions of 120 and 240 dpa at 475 °C. Field-emission transmission electron microscopy was used to characterize the cavity evolution. FC92–B exhibited the highest resistance to swelling among the irradiated alloys. The final volumetric swelling of FC92–B reached 1.3 % at 70 dpa and 2.9 % at 140 dpa. On the other hand, HT9 exhibited the highest swelling, reaching 7.4 % at 140 dpa. Comparing the present swelling results at 140 dpa/140 appm He with swelling data at 280 dpa/280 appm He from our previous study, it was observed that Gr.92 and FC92–N swelled more at 140 dpa/140 appm He than at 280 dpa/280 appm He. This negative correlation between swelling and dose in Gr.92 and FC92–N is primarily attributed to the helium-associated swelling suppression at higher helium concentration of 280 appm. A bimodal cavity size distribution appeared only in Gr.92 and FC92–N at 280 dpa/280 appm. This result demonstrates that the excess amount of helium over 200 appm promoted early-stabilization of new-born cavities, resulting in preferentially enhanced cavity nucleation, while impeding the growth of nucleated cavities. An inhibition in cavity growth possibly led to an extended duration of nucleation-dominant stages, finally suppressing swelling in ion-irradiated Gr.92 and FC92–N alloys.

In this study, we investigate the impact of hydrogen (H) ion and nickel (Ni) ion irradiation with energy of 1.5 MeV and a dose of 1 × 1015 ions/cm2 on the structure and giant magnetoimpedance (GMI) effect for amorphous Co64.5Fe4.5Cr3B10Si18 ribbons. Simulations using SRIM-2008.04 software show that the Ni impurity (H impurity) implanted by irradiation is distributed in a layer about 1 μm (2 μm) thick immediately next to the irradiated surface (near the middle of the thickness) of the ribbon. Ion irradiation with this energy and dose does not alter the amorphous structure, but the DC resistivity is increased by 1.5 times and increased only slightly in the case of irradiation with Ni and H ions, respectively. The GMI ratio and magnetic field sensitivity increase significantly in irradiated samples, reaching 157% and 8.6%/Oe (127% and 6%/Oe) in the case of Ni ion (H ion) irradiation. The skin depth of the Ni (H) ion-irradiated ribbon sample is larger (smaller) than that of the non-irradiated sample, but the transverse permeability μ T increases. Although ion irradiation reduces the saturation magnetization, as shown by the hysteresis loops and magnetization curves, the increase in μ T supports the enhancement of the GMI effect in the ion-irradiated ribbons. These research results will be beneficial for the development of highly sensitive GMI sensor applications. [ABSTRACT FROM AUTHOR]

The effect of artificially created 0D and 1D structural defects’ nanostructure formed by implanted dielectric nanoparticles or irradiation defects on microwave properties of high-Tc superconductor films is analysed based on the phenomenological theory for microwave response of type-II superconductors. The surface resistance is calculated for the Meissner and mixed states for such a kind of nanostructured type-II superconductor film. An emergence of nonlinear response caused by the entrance of microwave-induced vortices in the film interior through its edges is also theoretically explored. The obtained results demonstrate that artificial defect nanostructure inside the superconductor can significantly improve its microwave characteristics in both the Meissner states and the mixed ones and increase the range of the linear microwave response. We also present results of experimental studies on microwave properties of high-temperature superconductor (HTS) films with artificial defect nanostructure formed by heavy-ion irradiation. Noticeable decreases of the surface resistance and enhancement of the linear response range at low temperatures are observed for moderately irradiated HTS YBa2Cu3O7−x (YBCO) film exposed to irradiation by 3 MeV Au2+ ions at dose 1011 cm−2. These results are in agreement with the above-discussed phenomenological theory for microwave response of nanostructured superconductors. A theoretical model concerning the new unusual mechanism of the nonlinear radio-frequency (RF) response in multiband superconductors is also presented. This is a mechanism of nonlinearity based on the possible dissociation of Abrikosov’s vortices in multiband superconductors into fractional components under the strong RF current action. We have calculated the RF complex resistivity in two-band superconductors and grounded an emergence of specific peculiarities at critical current density values corresponding to the vortex depinning and dissociation.

The study reports the significance of carbon presence in affecting void nucleation in Fe. Without carbon, void nucleation rates decrease gradually at high temperatures but remain significantly high and almost saturated at low temperatures. With carbon present, even at 1 atomic parts per million, void nucleation rates show a low-temperature cutoff. With higher carbon levels, the nucleation temperature window becomes narrower, the maximum nucleation rate becomes lower, and the temperature of maximum void nucleation shifts to a higher temperature. Fundamentally, this is caused by the change in effective vacancy diffusivity due to the formation of carbon-vacancy complexes. The high sensitivity of void nucleation to carbon comes from the high sensitivity of void nucleation to the vacancy arrival rate in a void. The void nucleation is calculated by first obtaining the effective vacancy diffusivity considering the carbon effect, then calculating the defect concentration and defect flux change considering both carbon effects and pre-existing dislocations, and finally calculating the void nucleation rate based on the recently corrected homogeneous void nucleation theory. The study is important not only in the fundamental understanding of impurity effects in ion/neutron irradiation but also in alloy engineering for judiciously introducing impurities to increase swelling resistance, as well as in the development of simulation and modeling methodologies applicable to other metals. [ABSTRACT FROM AUTHOR]

Exposure of metals to neutron irradiation results in an increase in the yield strength and a significant loss of ductility. Irradiation hardening is also closely related to the fracture toughness temperature shift or the ductile-to-brittle transition temperature (DBTT) shift in alloys with a body-centered cubic (bcc) crystal structure. Ion irradiation is an indispensable tool in the study of the radiation effects of materials for nuclear energy systems. Due to the shallow damage depth in ion-irradiated materials, the nanoindentation test is the most commonly used method for characterizing the changes in mechanical properties after ion irradiation. Issues that affect the analysis of irradiation hardening may arise due to changes in the surface morphology and mechanical properties, as well as the inherent complexities in nanoscale indentation. These issues, including changes in surface roughness, carbon contamination, the pile-up effect, and the indentation size effect, with corresponding measures, were reviewed. Modeling using the crystal plasticity finite element method of the nanoindentation of ion-irradiated materials was also reviewed. The challenges in extending the nanoindentation test to high temperatures and to multiscale simulation were addressed. [ABSTRACT FROM AUTHOR]

Intercalation has recently emerged as a powerful tool due to its unique capability of modifying the properties of materials without breaking their chemical bonds. The ultrathin lattice structure of two‐dimensional (2D) materials with strong in‐plane covalent bonding and weak out‐of‐plane bonding between neighboring layers allow for the successful utilization of this powerful technique. The physics and chemistry of intercalated foreign species in 2D host materials, especially graphene and hexagonal boron nitride (h‐BN), are the focus of this review article. Among many foreign species, special attention is given to rare gas solids that introduce unprecedented physical and chemical properties in the targeted host materials. The historical background of intercalation is briefly discussed, and a comprehensive review of the very recent progress in the intercalation of rare gas solids in graphene and h‐BN is then provided. Different technologies used for the growth of the host materials and for the intercalation of rare gas species are also described. The remarkable potential of the resulting hybrid materials is outlined for diverse applications, including sensing, water filtration, and nanoelectromechanical devices. [ABSTRACT FROM AUTHOR]

High entropy ceramics are potential structural materials for advanced reactor concepts where numerous helium atoms would be produced due to the (n, α) nuclear transmutation reaction. However, the irradiation behaviors of high entropy ceramics are not well understood until now. In present work, the responses of high entropy (ZrTiNbTa)C 4 and its binary constituent ZrC ceramics to energetic He-ions irradiation have been studied. X-ray diffraction analysis showed that He-ions irradiation resulted in peak shift and broadening of diffraction peaks in both (ZrTiNbTa)C 4 and ZrC, which denotes lattice expansion and structural damages induced by the irradiation. Transmission electron microscope observation revealed that spherical helium bubbles distribute uniformly in the grain interiors of (ZrTiNbTa)C 4 while "string-like" bubbles with a preferred orientation are observed in ZrC grains. Nanoindentation characterization gives that the irradiation induced hardening of (ZrTiNbTa)C 4 is less definite than that of ZrC. The irradiation mechanisms of high entropy ceramics have been discussed. [ABSTRACT FROM AUTHOR]

Given their excellent superconducting properties, REBa2Cu3Oy (REBCO)-coated conductors (CCs) are anticipated to be utilized in a variety of magnet applications. To further increase the critical current density J c of these materials to levels needed for commercial applications, this study employs reel-to-reel (RTR) pulsed laser deposition (PLD) to fabricate REBCO+BaHfO3 (BHO) CCs. PLD creates BHO nanorods, which serve as flux-pinning defects. The material is subjected to O2+ irradiation to introduce more defects. The irradiation-induced defects serve as flux-pinning centers to the REBCO+BHO-nanorod CCs, increasing J c along the c axis and over a wide range of magnetic-field angles compared with conventional REBCO+BHO-nanorod CCs. Both nanorods and irradiation-induced defects are demonstrated to be effective pinning centers in this material. [ABSTRACT FROM AUTHOR]

Yttrium orthosilicate Y2SiO5 crystals, a member of the silicate family, are versatile and multifunctional materials when doped with rare earth or transition metal ions. However, there have been limited investigations into the impact of ion irradiation on the crystal structure of Y2SiO5 crystals to date. In this paper, the effect of microstructure, mechanical and optical properties of Y2SiO5 crystal before and after different fluences of carbon ions irradiation was investigated utilizing complementary characterization techniques. The results indicate that carbon ion irradiation caused lattice disorder and damage, which resulted in structural deterioration and changes in optical properties, such as decrease in the optical band gap energy (from5.77 eV to 5.44 eV), changes in the effective refractive index (neff) which resulted in the formation of “well + barrier” type and “barrier” type waveguides. In addition, elastic modulus increased after carbon ion irradiation. The results will be helpful for understanding the damage study of the Y2SiO5 crystal with carbon ion irradiation and proving that ion beam techniques can be used for material modification.

Abstract The magnetic phase transition is explored in CrSBr flakes through non‐magnetic ion irradiation, revealing a novel method for magnetic control in two‐dimensional (2D) materials. The rise and fall of the ferromagnetic phase is observed in antiferromagnetic CrSBr with increasing the irradiation fluence. The irradiated CrSBr shows ferromagnetic critical temperature ranging from 110 to 84 K, well above liquid N2 temperature. Raman spectroscopy reveals phonon softening, suggesting the formation of defects. These findings not only highlight CrSBr's potential in spintronics, but also present ion irradiation as an effective tool for tuning magnetic properties in 2D materials, opening new avenues for the development of spintronic devices based on air‐stable van der Waals semiconductors.

Abstract This study explores defect engineering in 2D materials using ion beam irradiation to modify the electrical and optical properties with potential in advancing quantum electronics and photonics. Helium and neon ions ranging from 5 to 7.5 keV are employed to manipulate charge transport in monolayer molybdenum disulfide (MoS2). In situ electrical characterization occurs without vacuum breakage post‐irradiation. Raman and photoluminescence spectroscopy quantify ion irradiation's impact on MoS2. Small doses of helium ion irradiation enhance monolayer MoS2 conductivity in field‐effect transistor geometry by inducing doping and substrate charging. Findings reveal a strong correlation between the electrical properties of MoS2 and the primary ion used, as well as the substrate on which the irradiation occurred. Using hexagonal boron nitride (h‐BN) as a buffer layer between MoS2 flake and SiO2 substrate yields distinct alterations in electrical behavior subsequent to ion irradiation compared to the MoS2 layer directly interfacing with SiO2. Molecular dynamics simulations and density functional theory provide insight into experimental results, emphasizing substrate influence on measured electrical properties post‐ion irradiation.

Polycrystalline specimens of copper oxide superconductors YBa2Cu3O7-δ(YBCO), Y0.39Sm0.30Eu0.31Ba2Cu3O7-δ(ME-REBCO), Y0.18La0.24Nd0.14Sm0.14Eu0.15Gd0.15Ba2Cu3O7-δ (HE-REBCO) were irradiated with 1 MeV-He ions at room temperature. Magnetization measurement using superconducting quantum interference device (SQUID) and microstructure observation using transmission electron microscope (TEM) were conducted before and after irradiation. The improvement of properties in HE-REBCO and degradations in YBCO, ME-REBCO were suggested by SQUID measurement. HE-REBCO had smaller irradiation defects and volume fractions although disappearance of twin boundaries due to tetragonal transition occurred in peak-damage area as well as YBCO. These defects work as optimal flux pinning centers leading to improve properties in HEREBCO.

Oxide-dispersion-strengthened (ODS) reduced-activation ferritic/martensitic (RAFM) steels are considered as most promising structural materials for fusion reactors and other advanced nuclear systems due to its excellent irradiation resistance under high dose irradiations. However, the extreme complex synergistic effect between transmuted helium/hydrogen and displacement damage which most seriously affects the structure and mechanical properties of ODS-RAFM steels is very difficult to understand, especially the role of hydrogen still remains unclear. Taking advantage of very sensitive to small vacancy clusters of Positron annihilation spectroscopy (PAS) method, we conducted irradiation defect study on ODS-RAFM, RAFM and its corresponding model alloy Fe–9Cr and α-Fe to investigate their anti-swelling properties at the early stage of irradiation with hydrogen-helium synergism and the mechanism. Three distinct irradiation schemes including (1) single Fe ion beam, (2) simultaneous Fe and He (named Fe + He) ion beam, (3) subsequent H ion injection after Fe + He (named Fe + He/H) ion beam irradiation were performed. Hydrogen-helium synergistic effects on vacancy evolution within these steels were explored combining the first-principles calculation. The implantation of He was observed to significantly increase defect concentration among all four steels, while H exhibited interestingly complexity on affecting the evolution of helium bubbles. The H post-injection increased defect concentration obviously in the materials with abundant sinks, but improved poorly in ones with rare sinks. Through the systematic study of the interactions between H, He, and vacancies, it was revealed that even at the early irradiation stage, ODS-RAFM steels has already exhibited excellent irradiation resistance compared to other alloys across three irradiation schemes.

As the lightest metal structural materials, magnesium (Mg) alloys offer extensive application potential. Gadolinium (Gd), as the primary alloying element in Mg alloys and recognized for its notable thermal neutron capture cross-section, is considered one of the most efficient neutron absorbers. Thus, the Mg–Gd alloy is highly expected to emerge as a material with remarkable neutron absorption capacity. Hence, in this study, the thermal neutron-shielding capabilities of Mg–Gd alloys were comprehensively examined by fabricating four as-cast Mg–xGd alloys with varying compositions (x = 0, 5, 10, and 15 wt%). The obtained results were further corroborated by sophisticated modeling and calculations using SuperMC. The results revealed a direct correlation between the thermal neutron absorption capacity of the Mg–Gd alloys and the increase in Gd content, with a noteworthy neutron attenuation factor of 22.33. Moreover, in an Au ion irradiation experiment conducted at 200°C, the Mg–15Gd alloy exhibited exceptional radiation resistance, with a displacement per atom (dpa) of 10. The matrix and second-phase regions were devoid of any cavity formation. Instead, a finite number of dislocation rings were observed, forming both leaf-like and granular Gd-rich nanoscale precipitates. This study underscores the versatility of Mg–Gd alloys as efficient neutron shielding materials and structural materials tailored for applications demanding radiation resistance in diverse environments.

Abstract We present green synthesis of silver nanoparticles in water using unirradiated and Ag $$^{15+}$$ 15 + ion irradiated phytoextracts of Bergenia Ciliata leaf, Eupatorium adenophorum leaf, Rhododendron arboreum leaf and flower. The use of different plant extracts and their subsequent ion irradiation allow for successful refinement of nanoparticle size and morphology. Due to changes in reducing and capping agents the nanoparticle surface functionalization also varies which not only controls the morphology but also allows for surface oxidation and aggregation processes. In this work, we have synthesized silver nanoparticles which exhibit sizes in the range from 13 to 24 nm and having shapes like spherical, quasispherical, trigonal, hexagonal, cylindrical, dendritic assemblies, and porous nanoparticles. Owing to changes in the size and shape of the nanoparticles, their direct bandgap (2.05 eV - 2.48 eV) and local surface plasmon resonance (420 nm - 490 nm) could also be tuned. These nanoparticles are examined as SERS substrates, where their enhancement factors, limit of detection for methylene blue, and SERS substrate homogeneity have been tested. It has been observed the nanoparticles synthesized using unirradiated plant extracts present an enhancement factor of 10 $$^6$$ 6 with a limit of detection 10 $$^{-8}$$ - 8 M. Whereas nanoparticles with refined morphology and shapes upon irradiation present high enhancement factors of >10 $$^7$$ 7 and detection limit down to 10 $$^{-9}$$ - 9 M. In addition, uniformity in Raman spectra over the SERS substrates has been obtained for selected Ag NPs substrates synthesized using irradiated extracts with minimum relative standard deviation in enhancement factor < 12%.

Photocatalytic technology has emerged as a crucial avenue for harnessing solar energy, presenting itself as a viable solution to address the current energy crisis and environmental pollution. The past 50 years have witnessed significant progress and breakthroughs in scientific research on photocatalytic technology. This paper provides a comprehensive review of the mechanism of photocatalytic technology and methods to improve the photocatalytic efficiency of semiconductor photocatalysts, such as TiO2 and ZnO. In this paper, common modification methods are divided into four categories: heterojunction construction, cocatalysts, defects, and morphological engineering. The origin and development of photocatalysts in each category are briefly summarized; moreover, the latest progress in each type of modification is discussed. S-scheme heterojunctions retain the high reduction and oxidation capacity of photogenerated electrons and holes by sacrificing half of the photogenerated carriers, showing excellent performance in photocatalysis and great application potential. The challenges associated with current modification schemes are presented. There is growing interest in quantitative and atomic-level modulation as attractive approaches to tackling these challenges. Regulating the electronic spin state and internal field is important for minimizing photogenerated carrier recombination in photocatalysis. This review will inspire researchers and promote the application of photocatalytic technology.

The emergence of the big data era has led to enormous demand for memory devices that are low cost, flexible, fabrication friendly, transparent, energy efficient, and have a higher density. Resistive random-access memory (RRAM) is an outstanding emerging non-volatile memory technology that has the potential to change the avenue of future storage devices. It is a promising technology owing to its attributes like minimal power usage, simple structure, long endurance cycles, high retention time, integrability with the existing complementary metal oxide semiconductor process (CMOS), and excellent scalability. It is highly attractive for several applications like neuromorphic computing, Internet of Things, non-volatile logics, hardware security, and radiation hardened electronics. Despite significant advances in the field of RRAM, materials and recent advanced techniques to enhance its performance have not been reviewed in detail. This paper provides an in-depth review of recent advancements in the field of RRAM, including the material used for fabrication and the methods to enhance the device performance. Advanced materials, especially transition metal oxides like copper oxide, nickel oxide, zinc oxide, tantalum oxide, titanium oxide, and hafnium oxide, used to fabricate RRAM devices are reviewed and their impacts on the performance have been discussed. The key figure of merits such as endurance, retention, and multi-bit capability are studied in relation to resistive switching memories. Several methods such as structure engineering, doping, annealing, light irradiation, plasma treatment, and ion irradiation used to enhance devices' performance are discussed. Furthermore, the impact of low and high energy ion irradiation on RRAM's electrical performance is provided in detail. Finally, this paper provides directions for future research in this field based on the findings of this review.

Tungsten (W) samples containing 0, 1, 3, and 5 at.% rhenium (Re) were irradiated by 20 MeV W ions to 0.5 dpa at 290 K and to 0.3 dpa at 1350 K. An additional set of samples was irradiated to 0.5 dpa at 290 K and then annealed at 1350 K. The irradiated samples were exposed to a deuterium (D) plasma at 370 K. D concentration profiles in the samples were measured using D(He3,p)α nuclear reaction analysis. The D binding states in the defects were analysed using thermal desorption spectroscopy (TDS). In the case of irradiation at 290 K, the trapped D concentration monotonically increases with increasing Re concentration: in W-5%Re it is 17% higher than in pure W. On the contrary, for irradiation at 1350 K the trapped D concentration monotonically decreases with increasing Re concentration: in W-5%Re it is 50 times smaller than in pure W. In the case of annealing at 1350 K of the samples irradiated at 290 K, the Re presence yields only up to three times reduction of trapped D concentration compared with pure W. TDS shows that the nature of D trapping sites is different for the irradiations at 290 K and 1350 K. We attribute the reduced D trapping in W-Re alloys irradiated at 1350 K to the reduction of cavity growth caused by the presence of Re.

Molecular dynamics has been used to carry out successive cascade simulations on model alloy Fe-Ni-Cr for three distinct primary knock-on atom (PKA) energies to elucidate the earlier experimentally obtained results of ion irradiation studies on SS316 and its Ti-modified version. The PKA energies used for the simulations were calculated using the stopping and range of ions in matter (SRIM-2013) to represent the irradiation of SS316 using 145 MeV Ne, 35 MeV He and 315 keV Ar ions. The simulation has been carried out successively to emulate the progress of irradiation and obtain results as a function of dose. The results for each PKA energy have been analysed to obtain the evolution of defect clusters in terms of their size, different types of dislocations, stacking fault probabilities, etc., in all three cases. The simulation results have been compared with our earlier experimental studies. [ABSTRACT FROM AUTHOR]

Pure iron (Fe) was subjected to singly charged 1 MeV Gold (Au+1), Nickel (Ni+1), Cobalt (Co+1), Copper (Cu+1), and Yttrium (Y+1) ions irradiation at a constant dose of 5 × 10 14 ions/cm2. X-ray diffraction analysis revealed polycrystalline nature of Fe with ions-induced changes in its crystallinity. Improvement in the crsytallinity of Fe due Au+1 irradiation was more significant as compared to the others. Similarly, the crystallinity of Fe was greatly decreased due to the impact of Y+1 ions. The Fe surface morphology indicated the surface defects in the form of pits, cavities and protruded structures after ions irradiation. Potentiodynamic Polarization (PDP) revealed an increase in the corrosion resistance of Fe after irradiation. The Au+1 ions irradiated specimen was found more effective in terms of high corrosion resistance than other specimens. The surface hardness of Fe exhibited Classical Hall–Petch relation, which demonstrated that the larger the crystallite size (26–83 nm), the smaller would be the surface hardness (190–182 HV) and vice versa. [ABSTRACT FROM AUTHOR]

This study reports on the magnetic hardening phenomenon of heavily helium ion-irradiated iron–chromium alloys. The alloys are important structural materials in next-generation nuclear reactors. In some cases, problems may arise when the magnetic properties of the materials change due to neutron irradiation. Therefore, it is necessary to understand the effects of irradiation on magnetism. Helium irradiation was conducted as a simulated irradiation, and the effect of cavity formation on magnetic properties was thoroughly investigated. High-quality single-crystal Fe-x%Cr (x = 0, 10, 20) films, with a thickness of 180–200 nm, were fabricated through ultra-high vacuum evaporation. Subsequently, irradiation of 19 dpa with 30 keV He+ ions was conducted at room temperature. X-ray diffraction measurements and electron microscopy observations confirmed significant lattice expansion and the formation of high-density cavities after irradiation. The magnetization curve of pure iron remained unchanged, while magnetic hardening was noticed in iron–chromium alloys. This phenomenon is believed to be due to the combined effect of cavity formation and changes in the atomic arrangement of chromium. [ABSTRACT FROM AUTHOR]

A metho d is proposed for measuring high-voltage charging potentials of dielectrics under ion irradiation by shifting the boundary of the bremsstrahlung X-ray spectrum. Since there is no bremsstrahlung output during Xe+ ion irradiation, it was proposed to use a probing electron beam to generate bremsstrahlung X-rays. To eliminate the effect of charge compensation on the surface, the value of the current of the probing probe of electrons was selected. The values of the equilibrium charging potentials of Al2O3 ceramics, Al2O3 sapphire, SiO2, and Teflon are obtained at different ion irradiation energies. The data obtained are compared with the results of spectrometric studies. [ABSTRACT FROM AUTHOR]

The paper describes a method developed in National Research Centre "Kurchatov Institute" for creating different functional nanostructures using ion beam irradiation. As an example, the formation of an integrated resistive elements in a low-temperature NbN superconductor nanowire is demonstrated. The possibility of producing an insulating layer of aluminum oxide with a thickness of 15 nm on the aluminum surface at room temperature under 0.2 keV oxygen ions irradiation was shown. [ABSTRACT FROM AUTHOR]

In this work, PVA/NaI consisting of polyvinyl alcohol (PVA) and sodium iodine (NaI) is irradiated using argon at fluence (45×10 1 6 , 90×10 1 6 , and 135×10 1 6 ion/cm2). The structure is investigated by XRD technique. The influence of argon ion is studied theoretically by SRIM/TRIM simulations. The target vacancies are recorded 46/ion, target displacements are 47/ion, and the replacements atoms are 1/ion. Also, the dielectric properties were determined in the frequency of 100 Hz to 5 MHz. With an average fluence 90×10 1 6 ions/cm2, electrical conductivity and dielectric constants have increased to twice their initial value. Additionally, after being exposed to an ion beam, the dielectric loss is reduced to around half of its original value. For both the control and irradiation samples, the attenuation and half layers were estimated. The dielectric characteristics of the irradiated samples were found to improve. Numerous uses, including energy storage and batteries, are rendered possible by these results. [ABSTRACT FROM AUTHOR]

Fatigue crack growth characteristics of ion irradiated compact tension (CT) specimens were evaluated in the Paris law region. Fatigue crack growth was monitored under tension‐tension loading and the thermoelastic response was measured. Two stages of crack propagation were identified. In the first 300,000 cycles, crack growth rates of irradiated and unirradiated specimens were comparable and plastic zone area was found to be independent of crack length. Beyond 300,000 cycles, irradiated specimens showed a greater crack growth rate; additionally, the plastic zone area increased with crack length. The increase in crack growth rate was attributed to irradiation hardening. The plastic zone area was found to be dependent on the crack path, especially in the initial stages of crack propagation. Local peaks in the value of the area of the plastic zone were found to be associated with greater crack tortuosity and secondary cracks. As a result, decreases in plastic zone area were associated with greater crack growth rates. Highlights: Heavy ion irradiation caused an increase in fatigue crack growth rate.Accelerated crack growth was attributed to irradiation hardening.Secondary cracks were found to correlate with identified peaks in plastic zone area.Drops in plastic zone area were associated with an increase in crack growth rate. [ABSTRACT FROM AUTHOR]

In order to find more excellent structural materials resistant to radiation damage, high-entropy alloys (HEAs) have been developed due to their characteristics of limited point defect diffusion such as lattice distortion and slow diffusion. Specially, refractory high-entropy alloys (RHEAs) that can adapt to a high-temperature environment are badly needed. In this study, T i Z r H f N b M o 0.1 RHEAs are selected for irradiation and nanoindentation experiments. We combined the mechanistic model for the depth-dependent hardness of ion-irradiated metals and the introduction of the scale factor f to modify the irradiation-hardening model in order to better describe the nanoindentation indentation process in the irradiated layer. Finally, it can be found that, with the increase in irradiation dose, a more serious lattice distortion caused by a higher defect density limits the expansion of the plastic zone. [ABSTRACT FROM AUTHOR]

An experimental study was made of the effect of high-fluence (>1018 cm–2) irradiation with helium and argon ions with an energy of 30 keV on the structure and morphology of the surface of carbon materials with significantly different microstructure: highly oriented pyrolytic graphite, glassy carbon, and carbon fibers made from polyacrylonitrile and viscose. [ABSTRACT FROM AUTHOR]

The effect of deformation nanostructuring on the ion-beam erosion of copper at a high fluence of irradiation with 30 keV argon ions is experimentally studied. To form an ultrafine-grained structure with a grain size of ~0.4 μm in copper samples with an initial grain size of about 2 μm, deformation nanostructuring by high-pressure torsion is used. It is found that when a layer with a thickness comparable to the grain size is sputtered, a steady-state cone-shaped relief is formed on the copper surface, the appearance of which does not change with increasing irradiation fluence. It is shown that the smaller the grain size in copper, the greater the concentration and the smaller the height of the cones on the surface. The cone inclination angles, close to 82°, as well as the sputtering yield of 9.6 at/ion, are practically independent of the grain size of copper, the thickness of the sputtered layer, and the irradiation fluence. Calculations using the SRIM program show that, when taking into account the redeposition of atoms from the walls of the cones, the sputtering yield of a cone-shaped copper relief Yc is 3.5 times less than the sputtering yield of a single cone, 1.2 times greater than the sputtering yield of a smooth surface, and the value of 9.25 at/ion is close to the experimentally measured one. [ABSTRACT FROM AUTHOR]

The effect of artificially created 0D and 1D structural defects' nanostructure formed by implanted dielectric nanoparticles or irradiation defects on microwave properties of high-Tc superconductor films is analysed based on the phenomenological theory for microwave response of type-II superconductors. The surface resistance is calculated for the Meissner and mixed states for such a kind of nanostructured type-II superconductor film. An emergence of nonlinear response caused by the entrance of microwaveinduced vortices in the film interior through its edges is also theoretically explored. The obtained results demonstrate that artificial defect nanostructure inside the superconductor can significantly improve its microwave characteristics in both the Meissner states and the mixed ones and increase the range of the linear microwave response. We also present results of experimental studies on microwave properties of hightemperature superconductor (HTS) films with artificial defect nanostructure formed by heavy-ion irradiation. Noticeable decreases of the surface resistance and enhancement of the linear response range at low temperatures are observed for moderately perirradiated HTS YBa2Cu3O7-x (YBCO) film exposed to irradiation by 3 MeV Au2+ ions at dose 1011 cm-2. These results are in agreement with the above-discussed phenomenological theory for microwave response of nanostructured superconductors. A theoretical model concerning the new unusual mechanism of the nonlinear radio-frequency (RF) response in multiband superconductors is also presented. This is a mechanism of nonlinearity based on the possible dissociation of Abrikosov's vortices in multiband superconductors into fractional components under the strong RF current action. We have calculated the RF complex resistivity in two-band superconductors and grounded an emergence of specific peculiarities at critical current density values corresponding to the vortex depinning and dissociation. [ABSTRACT FROM AUTHOR]

We present green synthesis of silver nanoparticles in water using unirradiated and Ag 15 + ion irradiated phytoextracts of Bergenia Ciliata leaf, Eupatorium adenophorum leaf, Rhododendron arboreum leaf and flower. The use of different plant extracts and their subsequent ion irradiation allow for successful refinement of nanoparticle size and morphology. Due to changes in reducing and capping agents the nanoparticle surface functionalization also varies which not only controls the morphology but also allows for surface oxidation and aggregation processes. In this work, we have synthesized silver nanoparticles which exhibit sizes in the range from 13 to 24 nm and having shapes like spherical, quasispherical, trigonal, hexagonal, cylindrical, dendritic assemblies, and porous nanoparticles. Owing to changes in the size and shape of the nanoparticles, their direct bandgap (2.05 eV - 2.48 eV) and local surface plasmon resonance (420 nm - 490 nm) could also be tuned. These nanoparticles are examined as SERS substrates, where their enhancement factors, limit of detection for methylene blue, and SERS substrate homogeneity have been tested. It has been observed the nanoparticles synthesized using unirradiated plant extracts present an enhancement factor of 10 6 with a limit of detection 10 - 8 M. Whereas nanoparticles with refined morphology and shapes upon irradiation present high enhancement factors of >10 7 and detection limit down to 10 - 9 M. In addition, uniformity in Raman spectra over the SERS substrates has been obtained for selected Ag NPs substrates synthesized using irradiated extracts with minimum relative standard deviation in enhancement factor < 12%. [ABSTRACT FROM AUTHOR]

Portable power supplies, particularly lithium‐ion batteries (LIBs), will play a key role in achieving sustainable development goals, and electrode active materials for the next generation of LIBs with higher energy density and longer life time is highly demanded. For this, in situ visualization of Li behavior during the charge/discharge process is essential, and transmission electron microscopy (TEM) will be promising for this purpose. Here, a quite simple experimental setup consisting of a newly developed Li–C nanocomposite film sputter‐deposited onto Au nanoprotrusions at room temperature and graphene synthesized on a W probe at 500 °C for the in situ TEM observation of the battery reaction is proposed. The preservation of the metallic Li in the Li–C film that is transferred to TEM without using any transfer vessels under atmospheric conditions is confirmed by high resolution TEM before the in situ electrochemical process in TEM. After the one cycle of the in situ electrochemical process, the intercalation of Li ions into graphene (lithiation) is clearly observed. Thus, it is concluded that the metallic Li stored in the Li–C film works well as the anode active material in the electrochemical process for solid state LIBs, implying the developed in situ experimental system is promising. [ABSTRACT FROM AUTHOR]

Ion irradiation combined with nanoindentation is a promising tool for studying irradiation-induced hardening of nuclear materials, including reactor pressure vessel (RPV) steels. For RPV steels, the major sources of hardening are nm-sized irradiation-induced dislocation loops and solute atom clusters, both representing barriers for dislocation glide. The dispersed barrier hardening (DBH) model provides a link between the irradiation-induced nanofeatures and hardening. However, a number of details of the DBH model still require consideration. These include the role of the unirradiated microstructure, the proper treatment of the indentation size effect (ISE), and the appropriate superposition rule of individual hardening contributions. In the present study, two well-characterized RPV steels, each ion-irradiated up to two different levels of displacement damage, were investigated. Dislocation loops and solute atom clusters were characterized by transmission electron microscopy and atom probe tomography, respectively. Nanoindentation with a Berkovich indenter was used to measure indentation hardness as a function of the contact depth. In the present paper, the measured hardening profiles are compared with predictions based on different DBH models. Conclusions about the appropriate superposition rule and the consideration of the ISE (in terms of geometrically necessary dislocations) are drawn. [ABSTRACT FROM AUTHOR]