Gd Ratio Research Articles

Phase engineered enhancement of photocatalytic and Opto-magnetic properties of CuO nanoparticles through fluorine and gadolinium doping

The present study comprises co-doping of CuO nanoparticles with gadolinium (Gd) and fluorine (F) using the sol-gel method to achieve phase stabilization and tune their physicochemical properties. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses revealed successful incorporation of the dopants and the stabilization of the CuO phase with increasing Gd content. Morphological studies revealed grain refinement and an enhanced surface-to-volume ratio upon co-doping. Average particle size decreased from 194 nm to 138 nm for pure and 5%F to 126 nm, 101 nm, and 81 nm for, 1mol%, 2mol% and 3mol% Gd along with 5mol% F co-doped CuO nanoparticles. Increasing the Gd ratio also tuned the band structure and significantly improved the optical properties of the CuO nanoparticles. Additionally, a transition from weak ferromagnetic ordering to paramagnetic behavior is observed. Coercivity decreased to 2.5 Oe for Cu0.97Gd0.03F0.05O0.95 as opposed to 396.3 Oe for CuF0.05O0.95. Photocatalytic activity studies using rhodamine B (Rh B) as a model probe revealed a pronounced enhancement in degradation kinetics with increasing gadolinium (Gd) doping, culminating in around 2.9 times faster degradation rate for 3 % Gd-doped CuO nanoparticles compared to pure CuO nanoparticles. After 3 h of UV light irradiation, the photodegradation efficiency of Cu0.97Gd0.03F0.05O0.95 was 94 %, which is significantly higher than the 80 % and 69 % efficiency of CuF0.05O0.95 and CuO, respectively. These remarkable optical, magnetic, and photocatalytic properties of the co-doped nanoparticles offer promising candidacy for various applications, including photocatalysis, solar energy harvesting, magnetic switching, and magnetic sensing.

Effect of monolayer ratio on single-shot all-optical switching in Gd/Fe multilayers

Ultrafast thermally induced magnetization switching (TIMS) with femtosecond lasers has attracted much attention due to its ability to trigger a single switching on the picosecond time scale. Currently, most of the studies on TIMS have focused on various ferrimagnetic alloys. In this paper, TIMS of Gd/Fe multilayers in different monolayer ratios is investigated by atomic spin dynamics. The results show that an increase in the monolayer Gd ratio narrows the energy density window of the switching. Further studies found that a lower damping ratio decreases the laser energy density threshold for magnetization reversal. Moreover, reducing the ratio of Gd in the monolayer at the appropriate energy density can shorten the duration of the transient ferromagnetic-like state, which can lead to faster realization of TIMS. Our simulation results provide new insights to explore the physical mechanism of TIMS in Gd/Fe multilayers.

Anthropogenic Gadolinium Anomalies in an Alluvial Plain with On-site Wastewater Treatment Systems in Campinas, SP, Brazil

Gadolinium anomalies have become a well-established marker for the pollution caused by wastewater, but there is not yet a standardized method to estimate the anomaly. Here, we compare four different published equations, distinct threshold values and reference normalizing values to estimate Gd anomalies by applying them to the results of a hydrochemical investigation in an alluvial aquifer with on-site sanitation systems. We measured traditional wastewater markers (such as electric conductivity, NO3_N, NH4–N, Cl-) and REE in groundwater samples collected from hand-dug wells in two seasons. The ratios of Gd normalized measured concentrations to Gd normalized geogenic concentrations (GdSN/Gd*) estimated with the various methods ranged from 0.7 to 2.8. It turned out that the choice of the equation and the threshold value can affect the decisions about anthropogenic pollution’s occurrence (or not). The normalizing values did not play a significant role in the decision. Based on measurement uncertainties and on the interpretation of hydrogeological conditions in the study area, a threshold value of 1.3 for defining anthropogenic Gd anomalies was deemed adequate for the study area. The occurrence of Gd anomalies higher than 1.8 in two wells, one in each season, reinforces the hypothesis that the groundwater is contaminated by the on-site sanitation systems in the study area, as intermittent detection of anthropogenic Gd is a characteristic of this pollution source.

Quantitative analysis of element substitution in mixed-vanadate LuxGd1-xVO4 single crystals at the atomic scale

In mixed crystals, two or more elements exhibit comparable properties and can be substituted freely. As a special type of “substitutional doping,” the properties of materials can be adjusted by altering the doping ratio of elements. Mixed-vanadate crystal LuxGd1-xVO4 is a promising laser host material with excellent chemical stability, mechanical property and thermal conductivity. The substitutional doping ratio of the two rare-earth elements determines the value of x. The thermal, optical, and laser properties of the material vary with x. However, the two types of atoms showing little difference in the same location in mixed crystals form substitutional solid solutions with alike atomic radii as well as electronic structures. Therefore, distinguishing comparable elements in mixed crystals at the atomic scale and quantitatively analyzing the doping ratio in mixed crystals are challenging. In this study, combining high-angle annular dark field (HAADF) and electron energy-loss spectroscopy (EELS), we accurately characterize the atomic structure of mixed-vanadate single crystal LuxGd1-xVO4 along the [111] orientation as well as the distribution of two rare-earth elements at the atomic scale. The ratio of Lu and Gd and the doping rules in the crystals are quantitatively analyzed. In addition, combined with the energy dispersive X-ray spectroscopy (EDS) results of the [100] crystal orientation, a uniform random distribution of Lu and Gd in the LuxGd1-xVO4 crystal is confirmed. This study provides a new means of understanding mixed-crystal structures and solves the problem of quantitative analysis of elemental doping in materials at the atomic scale, thus laying the foundation for exploring the relationships among composition, structure, and function in materials.

Empowering PVD for corrosion protection

SummaryA novel, monolithic DC‐magnetron sputtered TiN+MgGd coating, only 3to5 μm thick, effectively protects steel substrates from corrosion. This achievement is due to alloying of TiN with MgGd, which not only maintains the renowned wear resistance of TiN coatings, but potentially improves it through optimized deposition parameters.The key to the enhanced corrosion resistance lies in the addition of magnesium (Mg) and gadolinium (Gd). It reduces the coating's free corrosion potential, thereby mitigating the driving force for galvanic corrosion between coating and substrate. Moreover, at specific Mg to Gd ratios, a cathodic protection effect can be observed. Crucially, the presence of Gd is essential for this performance. It imparts hydrophobicity to the coating surface, reinforces a passivating layer and significantly enhances defect tolerance.This discovery paves the way for a sustainable alternative to electroplated chromium or combined electroplating and PVD, offering superior corrosion protection with minimal coating thickness.

Efficient photocatalytic degradation of ciprofloxacin by doped Bi4O5I2 with Gd3+ as an electron trap: Gd3+ substitutes Bi3+ in the lattice

Gd3+-doped Bi4O5I2 with a flower-like structure has been successfully prepared for the first time using a one-step hydrothermal method. The effect of different doping amounts on the photodegradation properties has been investigated. The total removal of ciprofloxacin (CIP) by 3 % Gd–Bi4O5I2 (molar atomic ratio of Gd to Bi = 0.03:1) under visible light irradiation was 94.50 % (within 120 min). The reaction rate constant was 6.3 times higher than that of pure Bi4O5I2. In complex water containing humic acid (HA) and various anions, 3 % Gd–Bi4O5I2 maintained a high total removal rate for CIP. UV–Vis diffuse reflectance spectroscopy and electrochemical tests have shown that doping Gd3+ not only extends the photoresponse range, but also reduces the photonic band gap width. Gd3+ ions act as electron traps to trap excited electrons and promote the separation and migration efficiency of photogenerated electron-hole pairs, improving the performance of Gd–Bi4O5I2 composites for the photocatalytic degradation of CIP.

Tailoring the degradation rate of magnesium-lithium alloy with alloying elements of gadolinium and nickel

To explore lightweight degradable materials that are more suitable for fracturing ball, Mg-8Li-4Gd-xNi (x = 0, 0.5, 1, 1.5 wt%) alloys for fracturing ball in petroleum extraction were prepared by vacuum induction melting. The features and formation of long-period stacking ordered (LPSO) doped with gadolinium (Gd) and nickel (Ni) were characterized. And the relationship between the degradation rate of alloys and the structure of LPSO in duplex Mg-Li alloys is investigated. The results show that network 24 R LPSO phase and punctate GdNi3 phase are formed with the addition of Gd and Ni. With the increase of Ni content, the shape of LPSO changes from intermittent network to continuous network and turns into an intermittent network again. The Mg-8Li-4Gd-1.5Ni alloy shows a significant increment in weight loss rate compared with the Mg-8Li-4Gd alloy by 75 times. Atomic force microscope (AFM) results show that the addition of Ni increases the potential difference between the second phase and the β-Li phase from 220 mV to 504 mV. It is difficult for forming LPSO due to higher fault energy when the atomic ratio of Gd to Ni is lower than 4:3, which promotes the LPSO to intermittent network. LPSO and GdNi3 provide higher potentials as cathodes in corrosion, forming a loose and porous corrosion product layer in the alloy. With the increase of Ni content, micro-galvanic corrosion effect is increased which results in a significantly higher corrosion rate of the alloy.

Reticular Chemistry of the Fcu-Type Gd(III)-Doped Metal-Organic Framework for T1 -Weighted Magnetic Resonance Imaging.

Nanoscale metal-organic frameworks (nanoMOFs) are emerging as an important class of nanomaterials for the systematical investigation of biomedically relevant structure-property relationship (SPR) due to their highly tailorable features. In this work, the reticular chemistry approach is shown to explore the SPR of a fcu-type Zr(IV)-nanoMOF for T1 -weighted magnetic resonance imaging (MRI). Isoreticular replacement of the eight-coordinated square-antiprismatic Zr(IV) by nine-coordinated Gd(III) brings a stoichiometric water capped on the square-antiprismatic site, enabling the relaxation transfer in the inner-sphere, giving the r1 value of 4.55 mM-1 ·s-1 at the doping ratio of Gd : Zr = 1 : 1. Then, these isoreticular engineering studies provide feasible ways to facilitate the relaxation transfer in the second- and outer-sphere of the Gd(III)-doped Zr-oxo cluster for the relaxation respectively. Finally, these in vitro and in vivo MRI studies revealed that the Gd(III)-doped Zr-oxo cluster aggregated underlying the fcu-type framework surpasses its discrete molecular cluster for MRI. These results demonstrated that there is plenty of room inside MOFs for T1 -weighted MRI by reticular chemistry.

Epoxide synthesis of binary rare earth oxide aerogels with high molar ratios (1:1) of Eu, Gd, and Yb

Epoxide synthesis of binary rare earth oxide aerogels with high molar ratios (1:1) of Eu, Gd, and Yb

Ferroelectric Tunnel Thin-Film Transistor for Synaptic Applications

In this work, a ferroelectric tunnel thin-film transistor (FeT-TFT) with polycrystalline-silicon (poly-Si) channel and ferroelectric HfZrOx gate dielectric is demonstrated with analog memory characteristics for the application of synaptic devices. The FeT-TFT exhibits a much lower conduction current of ∼0.032 times in transfer characteristics and maximum conductance (Gd) of ∼ 0.14 to 0.2 times in potentiation and depression operation than the FeTFT due to FeT-TFT’s carrier transport mechanism: interband tunneling. This work employed pulse widths of 75, 150, and 300 ns to modulate Gd, and it was found that using a pulse width of 75 ns could achieve low asymmetry ∼ 1 and high Gd ratio ∼ 20.63 under the consideration of operation speed. When the pulse time is increased, the potentiation and depression voltages can be significantly decreased to maintain the low asymmetry, but the Gd ratio is also reduced. In addition, the endurance characteristic of poly-Si FeT-TFT is found to be strongly related to the degradation effect of subthreshold swing due to the dynamic stress effect in the endurance measurement. This result reveals that the reliability of ferroelectric devices is not only owing to the degradation of the remanent polarization.

Synthesis Optimization of BaGdF5:x%Tb3+ Nanophosphors for Tunable Particle Size

X-ray photodynamic therapy (XPDT) is aimed at the treatment of deep-located malignant tumors thanks to the high penetration depth of X-rays. In XPDT therapy, it is necessary to use materials that effectively absorb X-rays and convert them into visible radiation-nanophosphors. Rare-earth elements, fluorides, in particular, doped BaGdF5, are known to serve as efficient nanophosphor. On the other hand, the particle size of nanophosphors has a crucial impact on biodistribution, cell uptake, and cytotoxicity. In this work, we investigated various Tb:Gd ratios in the range from 0.1 to 0.5 and optimized the terbium content to achieve the maximum luminescence under X-ray excitation. The effect of temperature, composition of the ethylene glycol/water solvent, and the synthesis technique (solvothermal and microwave) on the size of the nanophosphors was explored. It was found that the synthesis techniques and the solvent composition had the greatest influence on the averaged particle size. By varying these two parameters, it is possible to tune the size of the nanophosphor particles, which make them suitable for biomedical applications.

Effect of interfacial spin mixing conductance on gyromagnetic ratio of Gd substituted Y3Fe5O12

Due to its low intrinsic damping, Y3Fe5O12 and its substituted variations are often used for ferromagnetic layer at spin pumping experiment. Spin pumping is an interfacial spin current generation in the interface of ferromagnet and non-magnetic metal, governed by spin mixing conductance parameter G↑↓. G↑↓ has been shown to enhance the damping of the ferromagnetic layer. The theory suggested that the effect of G↑↓ on gyromagnetic ratio only comes from its negligible imaginary part. In this article, we show that the different damping of ferrimagnetic lattices induced by G↑↓ can affect the gyromagnetic ratio of Gd-substituted Y3Fe5O12.

Order–disorder structural tailoring and its effects on the chemical stability of (Gd, Nd)2(Zr, Ce)2O7 pyrochlore ceramic for nuclear waste forms

Series of unequal quantity Nd/Ce co-doped ceramic nuclear waste forms, (Gd, Nd)2(Zr, Ce)2O7, were prepared to tailor its ordered pyrochlore or disordered fluorite structure. The phase transition, microtopography, and elemental composition of the ceramic samples were systematically investigated, especially the effect of order-disorder structure on the chemical stability. It was confirmed that unequal quantity of Nd/Ce could synchronously replace the Gd/Zr-sites of Gd2Zr2O7. And the phase transition of order-disorder structure could be successfully tailored by regulating the average cationic radius ratio of (Gd, Nd)2(Zr, Ce)2O7 series. The elements of Gd, Nd, Zr, and Ce are uniformly distributed in the ordered or disordered structures. The MCC-1 leaching results showed that (Gd, Nd)2(Zr, Ce)2O7 pyrochlore ceramic nuclear waste forms had excellent chemical stability, whose elements' normalized leaching rates were as low as 10−4 -10−7 g‧m−2‧d−1 after 7 days. In particular, the chemical stability of disordered structure was superior to that of ordered structure. It was proposed that the force constant and the closest packing were changed with the structure transformation resulting the chemical stability difference.

BaGdF5 Nanophosphors Doped with Different Concentrations of Eu3+ for Application in X-ray Photodynamic Therapy.

X-ray photodynamic therapy (XPDT) has been recently considered as an efficient alternative to conventional radiotherapy of malignant tissues. Nanocomposites for XPDT typically consist of two components—a nanophosphor which re-emits X-rays into visible light that in turn is absorbed by the second component, a photosensitizer, for further generation of reactive oxygen species. In this study, BaGdF5 nanophosphors doped with different Eu:Gd ratios in the range from 0.01 to 0.50 were synthesized by the microwave route. According to transmission electron microscopy (TEM), the average size of nanophosphors was ~12 nm. Furthermore, different coatings with amorphous SiO2 and citrates were systematically studied. Micro-CT imaging demonstrated superior X-ray attenuation and sufficient contrast in the liver and the spleen after intravenous injection of citric acid-coated nanoparticles. In case of the SiO2 surface, post-treatment core–shell morphology was verified via TEM and the possibility of tunable shell size was reported. Nitrogen adsorption/desorption analysis revealed mesoporous SiO2 formation characterized by the slit-shaped type of pores that should be accessible for methylene blue photosensitizer molecules. It was shown that SiO2 coating subsequently facilitates methylene blue conjugation and results in the formation of the BaGdF5: 10% Eu3+@SiO2@MB nanocomposite as a promising candidate for application in XPDT.

A Long-Term Polydromic Function to Disentangle Personal Remittance, Migration and Employment in Agriculture in Order to Raise the GDP of the Donor aid Ratio in Five African Countries

Economic statistics concerning the quinquennial features of Agriculture employment (A), net Migration (M), Donor aid (D) and Personal remittances (P), available for over forty years from five West African countries have here been related to the GDP (G). The overall results of a multilinear regression (R2 0.84) have confirmed that the GD ratio, which is an index of aid efficiency, is significantly and positively driven by the PD ratio (high P and low D - favorable) and the PA ratio (high P and low A - favorable), but negatively driven by the PG ratio ( a higher D efficiency is obtained for constant G and lower P). A higher migration flux corresponds to a non-significant rise in the GD ratio. The five countries are clustered, by means of a principal component analysis, into three types. Partial least square regressions fitted to the GD ratio within each cluster provide a long-term polydromic function that highlights certain particular cluster features: reactive to forcing factors, such as Donor diminutions (SEN), active, as driven by Personal remittance (MLI), and mostly entropic for GMB, GNB and MRT. The learnt from the database is that Donor variations may follow different evolutions of the GD ratio in the three clusters.

Robust finite-temperature magnetization dynamics in ferrimagnetic Gdx(FeCo)1−x (x = 0 ∼ 0.44) nanospheres across angular-momentum and magnetization compensation points: An atomistic model simulation

We explored robust magnetization dynamics in ferrimagnetic Gdx(FeCo)1−x nanospheres of Gd compositions ranging from x = 0 to 0.44 at finite T = 0 – 1200 K temperatures using two-sublattice atomistic simulations based on the stochastic Landau-Lifshitz-Gilbert equation. It was found that the magnetization compensation and angular-momentum compensation temperatures vary remarkably with x and that the former temperature is always lower than the latter. Also, it was found that neither compensation temperature exists below a specific Gd composition of x = 0.22, but above which, both exist and increase with x. The ferromagnetic resonance (FMR) frequency remarkably increases at the angular momentum compensation composition, whereas the FMR frequency does not reach zero at the magnetization compensation composition. The significant difference in the FMR frequency between the two characteristic compensation points is ascribed to the contrasting effective gyromagnetic ratios of Gd and FeCo. Our present atomistic simulation study well reproduced the earlier experimental observations of such dynamic behaviors at both the angular-momentum and magnetization compensation points, which observations cannot be explained by the existing Kittel and Wangsness models. This work provides a better understanding of robust dynamic behaviors of ferrimagnetic nanospheres as functions of temperature and constituent sublattice composition, especially at and near the characteristic compensation points.

Preparation, luminescence and photofunctional performances of a hybrid layered gadolinium-europium hydroxide

The design and fabrication of rare earth ions incorporated into the inorganic/organic hybrid materials have attracted growing attention for seeking improved optical properties and photofunctional performances. In this paper, a novel hybrid composite based on the layered rare earth hydroxides was successfully prepared by the ion-exchange and intercalation chemical process. The rare earth elements in the composite contain gadolinium (Gd) and europium (Eu) and the molar ratio of Gd to Eu is kept constant at 1.9 : 0.1. Organic sodium dodecyl sulfonate and dye coumarin-3-carboxyllc acid are simultaneously incorporated into the layered rare earth hydroxides as supporting agent and light-harvesting antenna, respectively. The resulting hybrid layered rare earth hydroxides exhibit the enlarged interlayer distance with about 2.60 nm, and the chemical composition was confirmed through X-ray diffraction, carbon, hydrogen and nitrogen (CHN) elemental analysis, infrared spectroscopy, and thermogravimetric analysis. The layered solid compound shows the characteristic red emission corresponding to the 5D0→7F2 transition of Eu3+ ion, and the luminescence intensity of the optimized compound is greatly enhanced as compared to its corresponding nitrate and the hybrid composite without the introduction of dye molecule. The hybrid layered rare earth hydroxides can be exfoliated into bright colloidal solution, which show superior recognition capability to Cu2+ ion with the distinct luminescence quenching. The large quenching constant (1.4 × 104 L/mol) and low detection limit (0.35 μmol/L) are achieved for Cu2+ ion, implying a “turn-off” fluorescent sensor for Cu2+ detection. Moreover, a transparent film was prepared based on the colloidal solution and displays the typical red emission in folded shape. The new hybrid compound with enhanced luminescence and excellent photofunctional performances is expected to be applied in the fields of fluorescent sensing and flexible optical devices.

Imaging‐Guided Targeted Drug Delivery using Stimuli‐Sensitive Theranostic Nanoparticles: Characterization and In Vivo Trafficking Patterns

Purpose : In type 1 diabetes (T1D), the existing delivery systems for insulin all suffer from the inability to regulate insulin without patient intervention. A major unmet medical need is to develop innovative strategy, which would increase the efficacy of immune therapeutics but also, reduce their toxicity. Targeted drug carriers using polymeric nanoparticles (NP) holds particular promise to enhance the delivery of immunoregulatory agents to treat T1D. The aim of this study was to synthesize and characterize the in vivo trafficking patterns of stimuli-responsive, thermosensitive, immunoregulatory-carriers for potential use in image-guided targeted delivery and on site controlled release. Methods : A number of metal nanoparticles with hyperthermia magnetic (HMNs) properties made out of Gd-Zn-Fe were fabricated that intrinsically have the ability to self-regulate their heating level to the desired therapeutic range, Curie temperature (Tc). Production of particles of uniform size and shape was ensured by constant reaction kinetics and efficient physical and chemical reactions in solution. The particles morphology was examined using electron microscopy. The size distribution was evaluated using Malvern Nanosizer device. Magnetic resonance imaging (MRI) relaxivities of HMNs were measured over a range of 25-45°C. Non-targeted and MECA79-targeted HMNs were engineered using self-assembly nanoprecipitation method. Targeted trafficking of MECA79-HMNs in skin transplanted NOD mice with distinctive lymphatic draining to the draining lymph nodes (DLN) was evaluated. To be able to image the particles, particles were coated with IRDye 800CW. Using iBox, live fluorescence imaging was carried out 8 days post transplantation (24 hours post IV administration). Results : The temperature of HMN (with Tc 38-40°C) rose only up to the Tc when the particles were subjected to an oscillating magnetic field, and further increasing the intensity of the field did not increase heating beyond their Tc. Increasing Gd ratio modulated Tc linearly with amount of Gd-substituted Zn Ferrite particles (Figure 1A). NPs TEM micrograph showed a dispersion of spherical particles with a narrow size distribution (Figure 1B). MRI relaxivities, R1 and R2, showed linear increase of the relaxation rate. Twenty-four hours post IV administration, there was a significant increase in the trafficking of MECA79 conjugated particles as compared to the non-targeted NPs to the DLN in the skin transplanted NOD mice (Figure 2). Conclusion : Nanomedicine's application of ITS to T1D remains to be developed. While there are a number of delivery approaches that target the LN, virtually all of them rely on passive lymphatic absorption (i.e., intradermal injection). Data presented here represent major achievements to establish for the first time systemic delivery of particles to specific sites in diabetic mice. These experiments serve the basis for developing more of multifunctional NPs.

Correlation of Ba:Gd ratio and film thickness to the dielectric, ferroelectric and leakage current mechanism of nanostructure Ba1-xGdxTiO3 thin films

Perovskite Ba1-xGdxTiO3 thin films at different Ba:Gd ratios (0 = x ≤ 0.3, with 0.05 step) and film thicknesses have been fabricated in MFM configuration using sol-gel technique. The dielectric constant has been measured as a function of frequency in the range of 100 Hz and 1 MHz using impedance analyzer. The results show that at 1 kHz, ε decreases as Gd3+ ratio increases, which attributed to the reduction of tetragonality c/a ratio. Whereas, it increases as film thickness increases, which attributed to grain size increment. The ferroelectric hysteresis of the films is characterized using Sawyer-Tower circuit that shows a degradation for ferroelectric hysteresis as Gd+3 ratio increases due to permanent dipoles and grain size effect. Whereas, it enhances with film thickness due to grains enlargement. The leakage current has been analyzed via semiconductor parameter analyzer in the range from 0 to 8 V. It is found that at distinct electric field, the leakage current density reduces as Gd+3 ratio increases, resultant from grain size reduction. Whereas, it reduces as the film thickness increases according to inverse relation with film thickness. Moreover, SCLC, Schottky and Poole-Frenkel emission mechanisms have been modeled for the films to conclude that the former is the predominant mechanism.

Ultra-thin Al2O3−Sr(1−x)GdxTiO3 composite ceramics with high microwave absorption performance

Gadolinium (Gd)-doped perovskite SrTiO3 combining with Al2O3, Al2O3−Sr(1−x)GdxTiO3 (x varying from 0 to 0.3 in steps of 0.1) composite ceramics was synthesized by hot-press sintering in a vacuum. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectrometer (EDS), four-probe testing instrument, and vector network analyzer were utilized to study their phase and composition characteristics, micromorphology, electrical conductivity, electromagnetic and microwave-absorbing properties, respectively. The XRD, SEM, and EDS results demonstrated that Gd atoms were successfully doped into SrTiO3 crystal and substituted the Sr sites. As a result, Al2O3−Sr(1−x)GdxTiO3 with x = 0.2, which has the advantage of an ultra-thin thickness (0.341 mm), exhibits excellent absorbing properties with a broad bandwidth (90% microwave absorption) of 4.07 GHz in the X band. Furthermore, the present investigation illustrated that Al2O3−Sr(1−x)GdxTiO3 (x = 0.1, 0.2, and 0.3) could be applied in the X band for microwave absorption, with broadband width and ultra-thin thickness (≤ 0.35 mm), by controlling the molar ratios of Gd and the thickness.