Spectroscopic characteristics of Olgite (Ba,Sr)(Na,Sr)2Na[PO4]2 crystals doped with Sm ions

Sm³⁺ ions doped Olgite crystals (Ba,Sr)(Na,Sr)₂Na[PO₄]₂ were prepared by high temperature solid-state reaction. Sm²⁺ ions were obtained by X-ray irradiation reduction. The samples were investigated by X-ray diffraction, SEM, photoluminescence and decay curves measurements. In (Ba,Sr)(Na,Sr)₂Na[PO₄]₂, the influence of different mole ratios of Sr to Ba atoms on the crystal structure, reducing efficiencies of Sm³⁺ to Sm²⁺ and luminescence properties of Sm²⁺ ions were discussed. It is found that the conversion of Sm³⁺ → Sm²⁺ after X-ray irradiation is efficient in this phosphate. The emission of Sm²⁺ in this host after excitation into the 4f⁵ 5d¹ levels shows ⁵D₀ → ⁷F_J (J = 0, 1, 2) emission together with a broad emission band. The characteristic of Sm²⁺ ions luminescence was discussed.     

Effects of samarium on microstructures and tensile properties of Mg-5Al-0.3Mn alloy

Microstructures and tensile properties of Mg-5Al-0.3Mn-xSm (x = 0, 1, 2 and 3 wt.%) alloys prepared by metal mould casting method were investigated. It was demonstrated that Mg-5Al-0.3Mn alloy was mainly composed of α-Mg and β-Mg₁₇Al₁₂ phases. However, the other two precipitates (Al₁₁Sm₃ and Al₂Sm) were observed along grain boundaries in the alloys containing Sm. The amount of Al₁₁Sm₃ and Al₂Sm precipitates was increased with the increment of Sm content. Meanwhile, volume fraction of β-Mg₁₇Al₁₂ phase was decreased. Moreover, the morphology of β-Mg₁₇Al₁₂ was altered from bulk bone-like shape to spherical one. Tensile results showed that Mg-5Al-0.3Mn-2Sm alloy exhibited the highest tensile properties both at room temperature and 150 °C. Compared with ultimate tensile strength (UTS), yield strength (YS) and elongation (?) of Mg-5Al-0.3Mn alloy, UTS, YS and ? of Mg-5Al-0.3Mn-2Sm alloy were enhanced by 30%, 45% and 35% at room temperature, and by 17%, 48% and 96% at 150 °C, respectively. The improvement of tensile properties was attributed to the decreased amount of β-Mg₁₇Al₁₂ and its refined morphology, and high thermal stable Al₁₁Sm₃ and Al₂Sm precipitates which effectively prohibited dislocation movement and grain boundary sliding during deformation process.     

Magnetic properties of nano-clusters lanthanum chromite powders doped with samarium and strontium ions synthesized via a novel combustion method

A novel approach to synthesize a single-phase orthorhombic perovskite lanthanum chromite LaCrO₃ clusters doped with Sm³⁺ and Sr²⁺ ions via gel combustion route was reported. The producing materials were synthesized using metal nitrates as oxidizers and triethanol amine (TEA), N-butyl amine (NBA) or ethylene diamine (EDA) as a fuel. The effect of the annealing temperature, type of organic fuel and the variation of the samarium and/or strontium substitution and its impact on crystal structure, crystallite size, microstructure and magnetic properties of the LaCrO₃ powders formed was systematically studied. The results revealed that a well crystalline single phase of pure LaCrO₃ can be achieved at annealing temperature from 800 to 1000 °C for 2 h. Moreover, each organic carrier materials exhibited a different degree of effectiveness in the synthesis of the mixed oxide powders. The crystal structure was influenced by doped Sm³⁺ and/or Sr²⁺ ions. The crystallite size of the produced powders was increased with the increase the annealing temperature, increasing the Sm³⁺ ion and the decrease of Sr²⁺ ion substitution. The microstructures of the produced powders were found to be nanoclusters octahedra-like shaped. The saturation magnetization of the LaCrO₃ powders increased continuously with an increase in the Sm³⁺ ion concentration and it decreased with an increase in the Sr²⁺ ion up to 0.3 at annealing temperature of 1000 °C for 2 h. The maximum saturation magnetization (0.279 emu/g) was achieved at the Sm³⁺ ion molar ratio 0.3 and annealing temperature 1000 °C. Moreover, wide coercivities can be obtained at different synthesis conditions (49.25 to 522  Oe).     

Samarium diffusion in polycrystalline samarium sulfide

The diffusion of samarium in polycrystalline samarium sulfide with a superstoichiometric composition of Sm_1.13S has been studied at T = 1000 and 1100°C. It is concluded that Sm atoms predominantly migrate over the boundaries of monocrystalline domains of the polycrystalline sample. The diffusion coefficient varies within D ≈ 10⁻²−10⁻³ cm²/s. In the temperature dependence of the diffusion coefficient, the diffusion activation energy is evaluated at E ∼ 4.6 eV and the preexponential term at D ₀ ≈ 1.8 × 10¹⁵ cm²/s.     

Water driven enhanced photoluminescence of Ln (=Dy3+, Sm3+) doped LaVO4 nanoparticles and effect of Ba2+ co-doping

Well-dispersed Dy³⁺ and Sm³⁺ doped LaVO₄ nanoparticles have been synthesized at a relatively low temperature of 140 °C in ethylene glycol (EG), water, N,N′-dimethyl formamide (DMF) and mixed solvents. The samples prepared in water show mixed tetragonal and monoclinic phase where tetragonal planes are found to be dominated over the monoclinic planes. However, the samples prepared in EG and DMF show monoclinic phase. Due to the phase transformation of the samples prepared in water the luminescence intensity of these samples is highly enhanced than that of the samples prepared in EG and DMF. The mixed phase of the samples prepared in water transformed to pure monoclinic phase when heated at 900 °C. The luminescence intensity of Dy³⁺ and Sm³⁺ doped LaVO₄ prepared in EG are also enhanced when large divalent Ba²⁺ ions is used as co-activator. The optimum concentration for Ba²⁺ ions was found to be 1 at.% in both Dy³⁺ and Sm³⁺ doped systems. The prepared nanoparticles are subsequently dispersed in methanol and incorporated in polymer films of PVA which showed the characteristic emissions of Dy³⁺ and Sm³⁺ when irradiated under UV light.     

Influence of samarium doping on the phase stability and optical properties of calcium silicates derived from agro-food wastes

Calcium silicates are very stable and good hosts for luminescent materials. These calcium silicates are synthesized using cost-effective agro-food wastes such as rice husk ash and eggshell powder along with doping of samarium oxide [Ca_3?xSi₂O₇:xSm³⁺(x(%)?=?0.25, 0.50, 0.75, and 1.00)] via solid-state reaction method. X-ray diffraction confirms that the Ca₃Si₂O₇ phase co-exists with the monoclinic-Ca₂SiO₄ phase. An increase in doping concentration of Sm³⁺ enhances the Ca₂SiO₄ phase content. Two types of morphology can be seen in the SEM micrographs confirming the presence of two phases. Photoluminescence emission spectra contain peaks in the visible region. Characteristic emission peaks of Sm³⁺ are present along with strong peaks due to the titanium ions present in agro-food wastes. Commission International de'Eclairage (CIE) co-ordinates correspond to the green region, which is significantly different from the CIE co-ordinates of Sm³⁺ doped samples derived from mineral oxides. This study presents an alternate use of agro-food wastes for synthesizing visible light-emitting phosphors and presents a mechanism for stabilizing Ca₂SiO₄ in waste-derived samples.

     

Applications of Judd–Ofelt theory to praseodymium and samarium ions in phosphate glass

The Judd–Ofelt (J–O) theory has had a remarkable success in the characterization of radiative transitions in lanthanide doped solids. The purpose of this paper is to review the applications of the J–O theory to the Pr³⁺ and Sm³⁺ ions and to use this system as an occasion to appraise its validity and to clarify its limits. In this paper we dwell at length on the absorption and luminescence measurements of two glass samples doped with Pr³⁺ and Sm³⁺, because they are basic for the J–O treatment. The results obtained for the J–O theory application to phosphate glasses doped with Pr³⁺ and Sm³⁺ present two undesirable outcomes: (1) a positive value of parameter Ω₂ and (2) large uncertainties with which the three Judd–Ofelt parameters were obtained. The validity of the J–O theory for intensity analysis was also tested for Sm³⁺ doped in phosphate glass. The resulting Ω₂ was much lower than Ω₄. The first set parameters were obtained using all the levels for which f_exp. was available. The second set parameter values were evaluated without the ⁶F_1/2 and ⁶H_15/2 levels. The Ω_2,4,6 values given in these two sets clearly suggest that particular care should be taken while evaluating the Judd–Ofelt parameters as well as when these parameters are compared to other systems due to their strong dependence on the nature of levels.     

Sorption performance of light rare earth elements using zirconium titanate and polyacrylonitrile zirconium titanate ion exchangers

Lanthanum, cerium, neodymium, and samarium were sorption from aqueous solutions using zirconium titanate (ZrTi) and polyacrylonitrile zirconium titanate (PANZrTi) ion exchangers. The characterizations of prepared materials were performed using XRD, SEM, FTIR, TGA, and DTA techniques. The sorption behavior of various ions toward synthesized resin has been studied depending on reaction temperatures, pH values, and initial concentrations. The selectivity order found is Sm³⁺?>?Nd³⁺?>?Ce³⁺?>?La³⁺ on ZrTi-100, Ce³⁺?>?Sm³⁺?≈?Nd³⁺?>?La³⁺ on ZrTi-150, and Sm³⁺?≈?Ce³⁺?>?Nd³⁺?>?La³⁺ on PANZrTi depending on the condition of prepared ZrTi samples. The K_d for lanthanide ions was slightly decreased with temperature increased, which indicated the exothermic nature. The sorption data obtained for equilibrium conditions have been analyzed using the different isotherm models, and the applicability of these isotherm equations was compared by the correlation coefficients, R². It was established that the equilibrium isotherm models’ applicability follows the order: Langmuir?>?Dubinin– Radushkevich?>?Freundlich. It is found the Ce³⁺ has high adsorption capacity on each of ZrTi-100 and ZrTi-150, while Nd³⁺ has high adsorption capacity on PANZrTi.     

Preparation method and thermal properties of samarium and europium-doped alumino-phosphate glasses

The present work investigates alumino-phosphate glasses from Li₂O–BaO–Al₂O₃–La₂O₃–P₂O₅ system containing Sm³⁺ and Eu³⁺ ions, prepared by two different ways: a wet raw materials mixing route followed by evaporation and melt-quenching, and by remelting of shards. The linear thermal expansion coefficient measured by dilatometry is identical for both rare-earth-doped phosphate glasses. Comparatively to undoped phosphate glass the linear thermal expansion coefficient increases with 2 × 10⁻⁷ K⁻¹ when dopants are added. The characteristic temperatures very slowly decrease but can be considered constant with atomic weight, atomic number and f electrons number of the doping ions in the case of T_g (vitreous transition temperature) and T_sr (high annealing temperature) but slowly increase in the case of T_ir (low annealing temperature–strain point) and very slowly increase, being practically constant in the case of T_D (dilatometric softening temperature). Comparatively to undoped phosphate glass the characteristic temperatures of Sm and Eu-doped glasses present lower values. The higher values of electrical conductance for both doped glasses, comparatively to usual soda-lime-silicate glass, indicate a slightly reduced stability against water. The viscosity measurements, showed a quasi-linear variation with temperature the mean square deviation (R²) being ranged between 0.872% and 0.996%. The viscosity of doped glasses comparatively to the undoped one is lower at the same temperature. Thermogravimetric analysis did not show notable mass change for any of doped samples. DSC curves for both rare-earth-doped phosphate glasses, as bulk and powdered samples, showed T_g values in the range 435–450 °C. Bulk samples exhibited a very weak exothermic peak at about 685 °C, while powdered samples showed two weak exothermic peaks at about 555 °C and 685 °C due to devitrification of the glasses. Using designed melting and annealing programs, the doped glasses were improved regarding bubbles and cords content and strain elimination.     

The synthesis and the magnetic properties of Sm<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>BiY<Subscript>2–<Emphasis Type="Italic">x</Emphasis></Subscript>Fe<Subscript>5</Subscript>O<Subscript>12 </Subscript>nanoparticles

Sm _x BiY_2–x Fe₅O₁₂ (x = 0, 0.1, 0.2, 0.4, 0.6, 0.8) nanocrystals were fabricated by sol–gel method. Samples were characterized by powder X-ray diffraction (XRD), thermal gravity analysis (TGA) and differential thermal analysis (DTA), transmission electron microscopy (TEM), vibrating sample magnetometer(VSM). The samples were calcined at 850 °C and 1000 °C and the average size of the particles were determined by Scherrer’s formula . In this paper, we discussed the effect of Sm³⁺ substitution for Y³⁺ on magnetic properties of BiY₂Fe₅O₁₂. The magnetic properties of Sm _x BiY_2−x Fe₅O₁₂ are decreased with increasing content of Sm ion.     

Effect of Sm3+ on dielectric and magnetic properties of Y3Fe5O12 nanoparticles

The Sm³⁺ doped Y_3?xSm_xFe₅O₁₂ (x = 0–3) nanopowders were prepared using modified sol–gel route. The crystalline structure and morphology was confirmed by X-ray diffraction and atomic force microscopy. The nanopowders were sintered at 950 °C/90 min using microwave sintering method. The lattice parameters and density of the samples were increased with an increase of Sm³⁺ concentration. The room temperature dielectric (ε′ and ε″) and magnetic (μ′ and μ″) properties were measured in the frequency range up to 20 GHz. The room temperature magnetization studies were carried out using Vibrating sample magnetometer using filed of 1.5 T. Results of VSM show that the saturation and remnant magnetization of Y_3?xSm_xFe₅O₁₂ (0–3) decreases on increasing the Sm concentration (x). The low values of magnetic (μ′ and μ″) properties makes them a good candidates for microwave devices, which can be operated in the high frequency range.     

The influence of different alkaline earth oxides on the structural and optical properties of undoped,Ce-doped,Sm-doped,and Sm/Ce co-doped lithium alumino-phosphate glasses

Undoped, singly Sm doped, Ce doped, and Sm/Ce co-doped lithium alumino-phosphate glasses with different alkaline earth modifiers were prepared by melt quenching. The structure of the prepared glasses was investigated by FT-IR and Raman, as well as by optical spectroscopy. The effect of the optical basicity of the host glass matrix on the added active dopants was studied, as was the effect doping had on the phosphate structural units. The optical edge shifts toward higher wavelengths with an increase in the optical basicity due to the increased polarizability of the glass matrix, but also with increasing CeO₂ concentration as a result of Ce³⁺/Ce⁴⁺ inter valence charge transfer (IV-CT) absorption. The optical band gap for direct and indirect allowed transitions was calculated for the undoped glasses. The glass sample containing Mg²⁺ modifier ions is found to have the highest value (4.16 eV) for the optical band gap while Ba²⁺ has the lowest value (3.61 eV). The change in the optical band gap arises from the structural changes and the overall polarizability (optical basicity). Refractive index, molar refractivity R_m and molar polarizability α_m values increase with increasing optical basicity of the glasses. The characteristic absorption peaks of Sm³⁺ were also investigated. For Sm/Ce co-doped glasses, especially at high concentration of CeO₂, the absorption of Ce³⁺ hinders the high energy absorption of Sm³⁺ and this effect becomes more obvious with increasing optical basicity.     

Structure and magnetic property of CoFe2−xSmxO4 (x = 0–0.2) nanofibers prepared by sol–gel route

CoFe_2−xSm_xO₄ (x = 0–0.2) nanofibers with diameters about 100–300 nm have been prepared using the organic gel-thermal decomposition method. The composition, structure and magnetic properties of the CoFe_2−xSm_xO₄ nanofibers were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, inductive coupling plasma mass analyzer and vibrating sample magnetometer. The CoFe_2−xSm_xO₄ (x = 0–0.2) nanofibers obtained at 500–700 °C are of a single spinel structure. But, at 800 °C with a relatively high Sm content of 0.15–0.2 the spinel CoFe_2−xSm_xO₄ ferrite is unstable and the second phase of perovskite SmFeO₃ occurs. The crystalline grain sizes of the CoFe_2−xSm_xO₄ nanofibers decrease with Sm contents, while increase with the calcination temperature. This grain reduction effect of the Sm³⁺ ions doping is largely owing to the lattice strain and stress induced by the substitution of Fe³⁺ ions with larger Sm³⁺ ions in the ferrite. The saturation magnetization and coercivity increase with the crystallite size in the range of 8.8–57.3 nm, while decrease with the Sm content from 0 to 0.2 owing to a smaller magnetic moment of Sm³⁺ ions. The perovskite SmFeO₃ in the composite nanofibers may contribute to a high coercivity due to the interface pinning, lattice distortion and stress in the ferrite grain boundary fixing and hindering the domain wall motion.     

Applications of Judd–Ofelt theory to praseodymium and samarium ions in phosphate glass

The Judd–Ofelt (J–O) theory has had a remarkable success in the characterization of radiative transitions in lanthanide doped solids. The purpose of this paper is to review the applications of the J–O theory to the Pr³⁺ and Sm³⁺ ions and to use this system as an occasion to appraise its validity and to clarify its limits. In this paper we dwell at length on the absorption and luminescence measurements of two glass samples doped with Pr³⁺ and Sm³⁺, because they are basic for the J–O treatment. The results obtained for the J–O theory application to phosphate glasses doped with Pr³⁺ and Sm³⁺ present two undesirable outcomes: (1) a positive value of parameter Ω₂ and (2) large uncertainties with which the three Judd–Ofelt parameters were obtained. The validity of the J–O theory for intensity analysis was also tested for Sm³⁺ doped in phosphate glass. The resulting Ω₂ was much lower than Ω₄. The first set parameters were obtained using all the levels for which f_exp. was available. The second set parameter values were evaluated without the ⁶F_1/2 and ⁶H_15/2 levels. The Ω_2,4,6 values given in these two sets clearly suggest that particular care should be taken while evaluating the Judd–Ofelt parameters as well as when these parameters are compared to other systems due to their strong dependence on the nature of levels.     

Thermal Conductivity of Sm3S4 System with Mixed Valence Sm Ions

The thermal conductivity () and electrical resistivity () of mixed-valence compound Sm₃S₄ have been measured in the temperature range 5 to 300 K. The present results and those presented previously [1] for the thermal conductivity between 80 to 850 K are interpreted in terms of the temperature-dependent fluctuating valence of Sm ions. Sm₃S₄ crystallizes in the cubic Th₃P₄ structure, and the cations with different valences occupy equivalent lattice sites. Divalent and trivalent Sm ions are randomly distributed in the ratio of 1:2 over all possible crystallographic cation positions (Sm²⁺ ₂Sm³⁺ ₂S^2– ₄). The behavior of the Sm₃S₄ lattice thermal conductivity _ph is extraordinary since valences of Sm ions are fluctuating (Sm³⁺Sm²⁺) with a temperature dependent frequency. In the interval 20 to 50 K (low hopping frequencies), _ph of Sm₃S₄ varies as _ph T ^–1 (it is similar to materials with static distribution of cations with different valences): at 95 to 300 K (average hopping frequencies 10⁷ to 10¹¹ Hz), _ph changes as _ph T ^–0.3 (it is similar to materials with defects). Defects in Sm₃S₄ appear because of local strains in the lattice by the electrons hopping from Sm²⁺ ions (with big ionic radii) to Sm³⁺ ions (with small ionic radii) and back (Sm²⁺Sm³⁺), at T>300 K (high hopping frequencies), _ph becomes similar to materials with homogenous mixed valence states [1].     

Antiquenching effect of modifying cations on samarium clustering: Physical,structural and luminescent behavior of heavy metal borate glass systems

In this paper an attempt has been made to correlate the structural modifications and luminescence efficiencies by changing the environment of the glass network by modifying oxides. Sm³⁺ doped lead borate (SPB) and lead cadmium alumino borate (SCPB) glasses have been fabricated by melt quench technique at high temperature. The glass samples are characterized by XRD, FTIR, optical absorptions, fluorescence and density measurements. The effect of Sm³⁺ ion and glass host interaction on the emission spectra has been discussed in the view of the ionicity and covalency of hosts. The ratio of the intensities of electric to magnetic dipole emissions are calculated by varying both the concentration of the Sm³⁺ ion and the composition of the glass matrix. The XRD profile of all the glasses confirms their amorphous nature and FTIR spectrum shows the presence of BO₃ and BO₄ groups. These glasses have shown strong absorption bands in the visible (VIS and NIR) region and emit strong orange red wavelengths when excited by ultraviolet light. The concentration quenching has been noticed and ascribed to energy transfer through cross-relaxation between Sm³⁺ ions. Shifting of UV absorption edge towards longer wavelength with addition of Sm₂O₃ concentration has been observed. Incorporation of Al₂O₃ and CdO in 2nd glass system is responsible for strong effect on luminescence of the present glass system. Based on these results, an attempt has been made to throw some light on the relationship between the structural modifications and luminescence efficiencies in two different glass hosts as a laser active medium in the visible region. Moreover the optical basicity values were theoretically determined along with covalent behavior of two glass systems.     

Luminescence of trivalent samarium ions in silver and tin co-doped aluminophosphate glass

This work presents the spectroscopic properties of trivalent samarium ions in a melt-quenched aluminophosphate glass containing silver and tin. Addition of 4 mol% of each Ag₂O and SnO into the glass system with 2 mol% Sm₂O₃ results in Sm³⁺ ions luminescence under non-resonant UV excitation owing to energy transfer from single silver ions and/or twofold-coordinated Sn centers. Assessment of luminescence spectra and decay dynamics suggest the energy transfer mechanism to be essentially of the resonant radiative type. Moreover, a connection between the luminescent and structural properties of the rare-earth doped glass system was demonstrated. Raman spectroscopy characterization revealed that no significant variation in the glass matrix is induced by Sm³⁺ doping at the concentration employed. A comparison was made with a structural study performed on the Eu³⁺ doped system (containing 2 mol% Eu₂O₃ along with 4 mol% of each Ag₂O and SnO) where the radiative energy transfer mechanism was previously established. The data appears consistent regarding the lack of variation in glass structure upon the Eu³⁺ and Sm³⁺ doping in connection with the dominance of the radiative transfer in the matrix. Thermal treatment of the material leads to precipitation of Ag nanoparticles of a broad size range inside the dielectric as observed by transmission electron microspcopy. Assessment of ⁴G_5/2 excited state decay in Sm³⁺ ions shows no influence from the silver particles.     

Controllable synthesis and luminescence of YPO<Subscript>4</Subscript>:Ln<Superscript>3+</Superscript> (Ln = Eu and Sm) nanotubes

YPO₄:Ln³⁺ (Ln = Eu and Sm) nanotubes were synthesized by a precipitation process in the presence of SDS. The XRD results showed that all samples have a xenotime type tetragonal structure, indicating that doped rare earth ions have no influence on the phase. The SEM and TEM images showed that all samples are nanotubes. On basis of the morphology of samples and the properties of SDS, the possible formation mechanism was speculated. YPO₄:Eu³⁺ and YPO₄:Sm³⁺ nanotubes showed characteristic emission bands of Eu³⁺ and Sm³⁺ ions, respectively. For YPO₄:Eu³⁺/Sm³⁺ nanotubes, the codoping Sm³⁺ ions can enhance the emission intensity of Eu³⁺ ions.     

Photoluminescence and color tunability of γ-irradiated Tb3+–Sm3+-codoped oxyfluoride aluminoborate glasses

The main goal of this paper is to generate a warm white light through γ-irradiated Tb³⁺/Sm³⁺-codoped oxyfluoride aluminoborate glasses under 387 nm excitation xenon lamp. The transparent Tb³⁺/Sm³⁺-codoped oxyfluoride aluminoborate glass samples were prepared by melt-quenching technique. The energy transfer mechanism between Tb³⁺ and Sm³⁺ ions with an emphasis on the role of Al₂O₃/Al³⁺ is systematically studied before and after γ-irradiation. The characteristics of white light emission defined by chromaticity color coordinates and correlated color temperature are evaluated. In the present glass systems, the tuning of cold-to-warm white light as a function of Al₂O₃ and γ-irradiation is demonstrated.     

Emission (Gd3+ and Sm3+) and ESR (Gd3+) studies of La1−xLnxB3O6 (Ln = Gd,Sm; 0 ≤ x ≤ 0.2 for Gd; 0 ≤ x ≤ 0.1 for Sm) phosphors

Polycrystalline powders of rare-earth doped La_1?xGd_xB₃O₆ (0?≤?x?≤?0.2) and La_1?xSm_xB₃O₆ (0.0?≤?x?≤?0.1) phosphors were successfully prepared by a B₂O₃ flux method. All the phosphor samples are well characterized by powder X-ray diffraction (XRD), infrared (IR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) methods and fluorescence lifetime of Sm³⁺ ion. The XRD patterns show that La_1?xM_xB₃O₆ (M?=?Gd and Sm) adopt monoclinic with the I2/a space group. The SEM–EDS results confirmed the doping of Gd and Sm into LaB₃O₆ lattice. The IR and Raman spectra of these solid solutions gave distinctive bands corresponding to planar BO₃ and tetrahedral BO₄ groups. The photoluminescence (PL) spectra of La_1?xGd_xB₃O₆ gave a strong emission band, ⁶P_J?→?⁸S_7/2, at 310 nm. The PL spectra of La_1?xSm_xB₃O₆ phosphor showed orange-red emission at 598 nm when excited using light of wavelength of 402 nm. The results were obtained by the transition ⁴G_5/2?→?⁶H_7/2 of Sm³⁺ ions. The influence of dopant concentration on the emission profiles was studied. The ESR spectra of La_1?xGd_xB₃O₆ (x?=?0.02) gave a typical U-spectrum and spin-Hamiltonian parameters are deduced.