Pr Content Research Articles

A Study of Structural, Optical and Photoluminescence Properties of Pr3+ Ions Doped Sodium Bismuth Borosilicate Glasses.

In this work, the conventional melt quenching approach is used to synthesize the Pr3+ doped NaF-Bi2O3-B2O3-SiO2 (NBBS) glasses. The influence of Pr3+ ions on their spectroscopic and structural characteristics in glass network is investigated. The amorphous nature of the samples has been amply verified by X-ray diffraction patterns. FTIR spectra show distinct basic vibrational bands in borate and silicate structural components (in the range from 500 to 3750cm- 1). In the UV-visible range, the absorption spectra showed four Pr3+ ion absorption bands. Furthermore, in the absorption spectra, four Pr3+ ion absorption bands were observed in the NIR regions (1300-2470nm). While utilizing Tauc plots to assess optical bandgap (Eg), it is observed that as the concentration of Pr3+ increases from 0mol% to 1.5mol%, the bandgap decreases from 3.67eV to 3.50eV. In luminescence spectra, seven bands can be observed at about 483, 524, 534, 580, 604, 643, and 682nm as a consequence of Pr3+ ion transitions. Strong variations in the emission band's intensity are seen at around 604nm (3P0→3H6), after a progressive increase in Pr mol% in the glass matrix. According to CIE coordinates, emission changes from orange to reddish-orange as the quantity of Pr3+ ions rises.

EOL‐NiMH Batteries: An Alternative for Critical Raw Materials. Chemical Characterization by WD‐XRF

ABSTRACTNickel‐metal hydride (NiMH) batteries hold not only the base metals but valuable rare earth elements (RREs) like La, Ce, Pr, and Nd. Given the importance of resource recycling and assured supply of the contained metals in such wastes, the present study has focused on the development of an XRF method able to fully characterize these residues. In this study, a robust method for the chemical characterization of the anode and cathode by wavelength‐dispersive x‐ray fluorescence spectrometry was developed. For that, NiMH batteries were manually disassembled to obtain the active materials used in the anode and cathode, where critical raw materials are used. The results showed that NiMH batteries' anode is valuable due to the high concentrations of La, Ce, Nd, and Pr, apart from Ni. Besides, the cathode is quite rich in Ni. The different composition of these two materials justifies the need for a recycling process that separates these fractions in order not to dilute the number of RREs and Ni that can be recovered from these batteries when they are disposed of.

Pr-doped oxygen-vacancy-induced porous NiMoO4 cathode and MoS2-modified CNTs anode construct ultra-high-performance supercapacitors

In this study, sol-gel method was used to prepare NiMoO4 electrode materials doped with different concentrations of rare earth elements Pr, and the microstructure and phase structure of the samples...

Robust red-emitting glass phosphors with high color purity achieved through a novel energy transfer pathway in Pr3+/Sm3+ co-activation

For the first time, a series of Pr3+/Sm3+ co-activated Multicomponent Borosilcate glasses were prepared by melt-quench technique with a fixed concentration of Pr3+ ions (0.5 mol%) and varied concentrations of Sm3+ ions (0.1–1 mol%). An energy transfer route is predicted from the spectral overlap diagram of absorption band (Pr3+:3H4→1D2) and emission (Sm3+:4G5/2→6H5/2, 4G5/2→6H7/2) bands of the singly doped glasses. A comprehensive analysis of photoluminescence features imparted by the Pr3+/Sm3+ co-activation in Multicomponent Borosilcate glasses was investigated with 402 and 444 nm excitation wavelengths and confirmed the existence of energy transfer from Pr3+ to Sm3+ ions with red light emission of high color purity (100 %). Decay profiles and colorimetry analysis further revealed that this dazzling red luminescence feature, achieved via novel energy transfer pathways in the as-prepared glasses, could be useful for red emission applications.

Study of Pr doped nanocrystalline LiCoO2 cathode material for spintronic and energy storage applications: A theoretical and experimental analysis

In this study, Pr3+ substituted LiCoO2 lithium-rich cathode materials were prepared using the sol-gel auto-combustion technique to enhance cycling performance. LiCo1-xPrxO2 samples having Pr concentrations x = 0.00–0.10 were synthesized. X-ray diffraction (XRD) showed a rhombohedral structure with space group R-3m, further verified by the Rietveld refinement. Field emission scanning electron microscopy (FESEM) revealed the presence of distinct and well-defined submicron-scale grains. FTIR spectroscopy confirmed Co–O stretching bonds within 590–560 cm−1 and revealed peaks at around 560–590, 830–860, and 1320-1480 cm−1, which could be attributed to the electrochemical performance of Pr-doped species. Moreover, EDX spectroscopy confirmed the typical elemental peaks of only Co, Pr, and O, confirming the required phase presence. The cyclic voltammetry showed improved reversibility and stability due to Pr doping. The first-principles computations were performed using the lattice constant extracted from XRD measurements. The pure LiCoO2 with a semiconducting nature became half-metallic due to Pr doping (LiCo0.84Pr0.16O2). The magnetic properties indicate that LiCoO2 and LiCo0.84Pr0.16O2 exhibit positive magnetic order, which shows that these are suitable candidates for spintronic applications. The pure LiCoO2 revealed intercalation voltages of 4.10–2.73V and a theoretical capacity 40–203 mAh/g. Meanwhile, for LiCo0.84Pr0.16O2, the intercalation voltages and theoretical capacity improved to 4.42–2.85 V and 42 to 211 mAh/g, respectively. The combined experimental and theoretical study suggests that Pr-doped LiCoO2 is suitable for spintronic applications and energy applications such as composite cathodes.

Structural, magnetic, and magnetostrictive properties of Prx(Tb0.27Dy0.73)1‒xFe1.95 polycrystalline

Magnetostriction materials are a significant kind of magnetic functional materials, while RFe2 (R = rare earth) compounds, especially Tb0.27Dy0.73Fe2, with cubic Laves phase structure, are the most famous. In this work, polycrystalline Prx(Tb0.27Dy0.73)1–xFe1.95 (x = 0, 0.05, 0.10, 0.15, 0.2, 0.25) alloys were synthesized to explore the influence of adding Pr on the structural, magnetic and magnetostrictive properties of Tb0.27Dy0.73Fe1.95. The results show that Prx(Tb0.27Dy0.73)1–xFe1.95 alloys can form the C15 Laves phase when x ≤ 0.2. Meanwhile, the samples with a Pr content of up to 0.1 exhibit a higher saturation magnetostriction compared to the Pr-free sample. As the content of Pr in Prx(Tb0.27Dy0.73)1–xFe1.95 rises from 0 to 0.1, the saturation magnetostriction, λs, improves from 1057 ppm to 1147 ppm. The apparent enhancement of the magnetostrictive property of Tb0.27Dy0.73Fe1.95 reveals the great potential of (Pr,Tb,Dy)Fe2 to become a widely-used magnetostriction material. Larger lattice distortion of the material itself leads to an increase in magnetostriction.

Deciphering the link: A cutting-edge exploration of the intriguing connection between recurrent pregnancy loss and rare earth elements-Lutetium, praseodymium, samarium, dysprosium, and cerium.

To evaluate the levels of serum rare earth elements (REEs): lutetium [Lu], praseodymium [Pr], samarium [Sm], dysprosium [Dy], and cerium [Ce] in pregnant women with recurrent pregnancy loss (RPL) and evaluate their relationship with total antioxidant capacity (TAC) and 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of DNA damage. A case-controlled study was conducted on a cohort of 60 female participants, with first-trimester healthy pregnant women as the control group and pregnant women with a history of consecutive abortions as the recurrent pregnancy loss (RPL) group. Following blood collection, serum concentrations of Lu, Pr, Sm, Dy, and Ce were measured using an inductively coupled plasma mass spectrophotometer (ICP-MS). Oxidative stress and DNA damage were evaluated through TAC and DNA damage marker (8-OHdG). Serum levels of Lu, Pr, Sm, Dy, and Ce were higher in women with RPL compared with control (P < 0.001). Intriguingly, a strong significant negative correlation was observed between TAC and REEs (P < 0.05). Lu, Dy, and Ce demonstrated a significant positive correlation with increased DNA damage in the RPL group (P < 0.05). Contrary, there was no evidence of a correlation between 8-OHdG and Pr and Sm. The study highlights a potential association between Lu, Sm, Dy, and Ce and an increased risk of RPL, highlighting REE-induced toxicity as a major risk factor for RPL. The outcome of the study is to advance our understanding of the interplay between rare earth elements and RPL, with potential implications for reproductive medicine, environmental health, and the development of preventive strategies for individuals at risk of RPL.

Tunning Pr to achieve ultra-high magnetic properties of anisotropic nanocrystalline (Sm,Pr)Co5 magnets

In this study, we reported on the bulk anisotropic nanocrystalline Sm1-xPrxCo5 (x = 0.2–0.6) magnets aimed at achieving excellent energy products. Through a combination of advanced processing techniques, including melt spinning, hot pressing, and hot deformation process, bulk magnets with a fine nanocrystalline structure were successfully synthesized. The results revealed that the substitution of Pr strengthened the c-axis texture and the saturation magnetization, facilitating the enhancement of remanence (Mr) and maximum magnetic energy product [(BH)max]. However, Pr substitution decreased the coercivity (Hci) due to the reduced magnetocrystalline anisotropy field. Excellent magnetic properties are obtained for Sm0.4Pr0.6Co5 magnets with the (BH)max of 23.2 MGOe and Hci of 11.8 kOe. The prepared (Sm,Pr)Co5 magnets with different Pr contents have essentially the same microstructure with RECo5 main phase grains of about 400 nm in diameter and fine dispersed rare earth-rich nanoprecipitates. Our findings can provide reliable reference for manufacturing nanocrystalline permanent magnet materials and promote the development of rare earth permanent magnet new materials.

Blue to UV upconversion properties of Pr3+ doped ACaF3 (A = K, Rb, Cs) phosphors

Materials capable of converting visible light into the ultraviolet C (UVC) region are promising candidates for antimicrobial technology and photocatalytic applications. In this work, the effective UVC upconversion phosphors ACaF3:Pr3+ (A = K, Rb, Cs) were synthesized using solid state reactions. Upconverted emissions in the range from 230 to 315 nm were obtained with 444 nm laser excitation. The dependence of upconverted luminescence on pump power, the concentration of Pr3+ ions, and the decay profiles of upconverted luminescence provide insights into the primary mechanisms responsible for upconversion. Among the obtained fluoroperovskites, the rubidium composition showed the most intense luminescence. Additionally, ACaF3:1 %Pr3+ exhibits a manifold increase in upconversion emission compared to the previously studied reference material LiYF4:1 %Pr3+, indicating the potential use of fluoroperovskites for surface decontamination.

Grain refinement for indium zinc oxide ceramic targets by praseodymium doped induced blocked boundary migration

How to refine the grain has been a difficult problem in the preparation of high-performance ceramic targets. In this work, the doping-induced grain refinement strategy was proposed, indium zinc oxide doped with different concentrations of Pr (Pr-doped IZO, PrIZO) targets were obtained by optimizing the sintering time and holding temperature. Effects of Pr doping content on the density, phase microevolution, grain size and resistivity during the densification process as well as the kinetics of the grain growth and the mechanism of grain refinement of PrIZO targets were investigated in detail. The results demonstrated that PrIZO targets with the atomic ratios of Pr:In:Zn = 0.01-0.03:1:1 all exhibited the excellent performance with high densification (>99.10 %) and mere average grain size (<3.0 μm) at low sintering temperature of 1350 °C. Additionally, XRD and EDS analysis indicated that PrIZO targets were composed of In2O3 and Zn3In2O6 with slight PrInO3, which formed by the limited solid solubility of Pr element. Combined with theoretical calculations, it inferred that the mechanism of grain refinement was attributed to the solute transformation and fine PrInO3 distributed at the grain boundaries of In2O3 phases, which produced the drag effect of grain boundary migration, then hindering the further growth of grains.

Effects of Pr substitution in Y1-xPrxBaCo3ZnO7+δ (0 ≤ x ≤ 0.5) cathodes for intermediate temperature solid oxide fuel cells

In this investigation, we successfully synthesized a series of Swedenborgite-type Y1-xPrxBaCo3ZnO7+δ (x = 0.0, 0.1, 0.2, 0.3, 0.4, and 0.5, abbreviated as YPxBCZ) oxides by a solid-state reaction method. The results show that YPxBCZ (x = 0.0, 0.1, 0.2, and 0.3) are single-phase structures, but YP0.4BCZ and YP0.5BCZ show interesting self-assembled composite phases. After long-term phase stability testing, YP0.3BCZ showed the best thermal stability. All samples show good chemical and thermal compatibility with La0.9Sr0.1Ga0.8Mg0.2O3-δ electrolyte. The thermal expansion coefficients in the temperature range from 30 °C to 1000 °C are equal to 9.8-13.1 × 10−6 K−1, close to that of the LSGM electrolyte. It is also found that Pr doping improves high temperature conductivity of YPxBCZ. The conductivity of YP0.3BCZ, YP0.4BCZ, and YP0.5BCZ reach 15.1, 18.5, and 22.5 S cm−1 at 800 °C. In addition, the area specific resistance (ASR) value decreases as the Pr content increases (0.038, 0.033, and 0.027 Ω cm2 at 800 °C for YP0.3BCZ, YP0.4BCZ, and YP0.5BCZ), improving the catalytic activity of the material. Another interesting finding was that the ASR of samples subjected to high temperature thermal decomposition was not adversely affected by the presence of decomposition products. The maximum power densities of YP0.3BCZ, YP0.4BCZ, and YP0.5BCZ in the single cells at 800 °C were 845, 930, and 1044 mW cm2, respectively. These results indicate that YP0.3BCZ, YP0.4BCZ, and YP0.5BCZ are promising cathode materials for intermediate-temperature solid oxide fuel cell.

Influence of Pr3+ co-doping on the luminescent properties of CGA:2 at.% Ho single crystal fibers

Ho3+, Pr3+ co-doped CaGdAlO4 (Ho,Pr:CGA) crystal fibers were successfully grown by the micro-pulling-down (μ-PD) technique for the first time. Detailed investigations were conducted on the polarized absorption spectra, fluorescence spectra, and lifetime decay curves. The 2 at.% Ho, 0.4 at.% Pr:CGA crystal fiber exhibits a broad absorption band at 1147 nm with full width at half maximum (FWHM) of 25.5 nm and 64.5 nm for σ and π polarization, respectively. Increasing the concentration of Pr3+ led to a decrease in emission intensity at 2001 nm and an increase in emission intensity at 2861 nm. The FWHMs of the crystal fiber containing 2 at.% Ho and 0.4 at.% Pr:CGA at 2861 nm were 44.5 nm for σ polarization and 24.3 nm for π polarization. Additionally, the lifetime ratio (5I7/5I6) decreases from 25.18 to 2.85 in the crystal fibers containing 2 at.% Ho:CGA and 2 at.% Ho, 0.4 at.% Pr:CGA, respectively. These findings suggest that the presence of deactivated Pr3+ ions can significantly reduce the lifetime gap between the 5I6 and 5I7 energy levels, potentially mitigating the self-termination phenomenon on the ∼3 μm emission.

Praseodymium doping-induced band structure tunning in bismuth ferrite (Bi1-xPrxFeO3) nanofibers for the enhanced photocatalytic properties

The study investigates the influence of praseodymium (Pr) doping on bismuth ferrite (BiFeO3/BFO) nanofibers and their structural, morphological, magnetic, optical, and photocatalytic properties. A series of bismuth ferrite nanofibers with varying concentration of Pr (Bi1-xPrxFeO3, x = 0.00, 0.05, 0.10, and 0.15 mol%) were successfully synthesized using an electrospinning technique. XRD patterns revealed that structural transformation occurred from rhombohedral to orthorhombic upon effective doping of Pr3+ into BFO nanofibers. The X-ray photoelectron spectroscopy analysis confirmed that Bi, Fe, and O maintained their native oxidation states of +3 and -2, respectively in the bare and doped systems. Furthermore, the optical band gap value was significantly reduced from 2.35 to 2.22 eV as well as the recombination rates of charge carriers in the doped systems, especially in BP0.15O system. The photocatalytic performance of the prepared samples was studied by measuring the decomposition of rhodamine B (RhB) under sunlight irradiation. Outcomes showed that the doped-BFO nanofibers exhibited enhanced photocatalytic performance compared to pure BFO, with the BP0.15O system showing the 98 % degradation in 60 min. This enhancement could be attributed to the presence of Pr-energy levels, which facilitating enhanced separation, and charge transfer to the surface for the effective redox reactions.

Half-metallic ferromagnetism with high critical temperatures in Substitutionally Doped Rare-Earth 2D Germanene

This work delves deep into the exploration of Rare-earth (RE) replacement doping germanene monolayers, where RE elements stand out for their fascinating electronic and magnetic nature derived from the elusive f-orbitals. Employing density functional theory (DFT) calculations, we unveil the electronic and magnetic characteristics of doped germanene systems. With its two-dimensional honeycomb structure, germanene holds immense promise for a wide range of applications within group IV materials. Through the discussion, we deeply uncover how the substitution of two specific concentrations of RE-atoms, namely La, Ce, Pr, Nd, Sm and Pm, transforms semi-metallic non magnetic germanene to half-metallic ferromagnets with remarkably high critical temperatures, when Hubbard correction is considered. These revelations not only deepen our comprehension of integrating f-orbitals into germanene but also open up exciting avenues for advancements in spintronic devices and beyond.

On the Selection of Catalysts’ Support with High Oxygen Delivery Capacity for DRM Application: Interest of Praseodymium as Dopant of Ceria

AbstractIn the present work, a series of supports with varying compositions (ranging from pure CeO2 to pure PrO2-y) was designed to investigate their ability to release oxygen (with the concomitant formation of oxygen vacancies) under diverse reducing atmospheres: hydrogen (H2), helium (He), and in the presence of a carbonaceous substance that mimics eventual carbon deposits formed under practical reaction conditions (DRM). Oxygen vacancies were generated effectively in all three atmospheres (following the order He &lt; H2 &lt; carbon material). With regard to the influence of the composition, the capability to generate oxygen vacancies clearly increased with the Pr content, for whatever the conditions tested. Notably, the non-stoichiometry obtained with the support of pure praseodymia in both inert and reducing atmospheres is very remarkable, as it approaches the maximum non-stoichiometry value of the well-established theoretical Bevan cluster. This leads to consider this formulation as a very promising support for applications in catalysis and other fields where oxygen vacancies play a crucial role. Dry Reforming of Methane requires catalytic supports that possess highly mobile oxygen, enabling it to actively participate in the reactions step involved or potentially gasify undesirable carbon deposits generated during parallel reactions. Consequently, designing and elucidating the behavior of ceria-praseodymium-based supports with high reducibility and generation of oxygen vacancies (oxygen storage and release capacity) holds particular relevance in this context. Actually, the very preliminary results comparing two counterpart formulations (5%Ni/PrO2-y versus 5%Ni/Al2O3) already confirm the suitability of the choice of pure praseodymia in terms of activity, stability and very high selectivity towards H2 and CO, reaching a very close value to the ideal H2/CO ratio of 1.

Phase structure and electrochemical properties of A5B19 La0.8-xPrxMg0.2Ni3.8 (x = 0–0.3) hydrogen storage alloy anode material

The La0.8-xPrxMg0.2Ni3.8 (x = 0, 0.05, 0.1, 0.2, 0.3) alloy were synthesized useing the induction melting method. X-ray diffraction, scanning electron microscope, electron probe micro analyzer, and electrochemical tests were used to analyze the structure and electrochemical performance of the La0.8-xPrxMg0.2Ni3.8 (x = 0–0.3) alloy. It was studied how the Pr element affected the electrochemical characteristics and microstructure of the A5B19 La-Mg-Ni based hydrogen storage alloy. The results show that the alloy consists of the CaCu5-LaNi5 phase, 2 H-Pr5Co19 phase, and 3R-Ce5Co19 phase. The abundance of the A5B19 phase increase with the increase of Pr content, while the abundance of the LaNi5 phase decrease, and the addition of Pr promotes the formation of the 2 H-Pr5Co19 phase. According to the results of the electrochemical test, every sample has good activation qualities, and the activation can be completed in 3–4 times. The activation properties are not significantly altered by the addition of Pr. The maximum discharge capacity increases at first, then decreases, reaching the highest 371.15 mAh g−1 at x = 0.2. The cyclic stability gradually improves with increasing content of Pr, and the maximum capacity retention rate reaches 85.80 % after 100 cycles. The primary factor influencing the alloy's high rate discharge ability is the exchange current density. With the increase of the exchange current density, the high rate discharge performance is gradually enhanced.

In vitro response of sugarcane (Saccharum spp. Hybrid) plantlets to flooding stress

Flooding caused by climate change puts the productivity of sugarcane cultivation at risk. The objective of this study was to evaluate the effect of in vitro flooding stress on sugarcane plantlets. Sugarcane plantlets were grown in test tubes containing Murashige and Skoog semi-solid medium without growth regulators as a control treatment and two stress levels using a double layer with sterile distilled water to simulate hypoxia and anoxia. After 15 d of culture, the number of new shoots, plantlet height, number of leaves, number of roots, root length, stomatal density, percentage of closed stomata and percentage of dry matter were evaluated. In addition, biochemical variables such as chlorophylls, carotenoids, phosphoenolpyruvate (PEP), Rubisco, total proteins (TP), proline (Pr), glycine-betaine (GB), phenols, antioxidant capacity and lipid peroxidation were determined in all treatments. Results showed a higher number of new shoots, leaves and percentage of closed stomata in the flooded plantlets, while plantlet height, number of roots, stomatal density, and dry matter were higher in the control treatment. Regarding, chlorophyll, carotenoid, PEP and Rubisco contents decreased in the flooded treatments, while TP and phenol contents were higher in the partially submerged treatment. Antioxidant capacity and lipid peroxidation increased in the fully submerged treatment. Pr and GB contents did not show changes in any of the evaluated treatments. Stress induced by excess water in a double layer in vitro is an alternative method to determining physiological and biochemical mechanisms of tolerance to hypoxia and anoxia caused by flooding for breeding programs in sugarcane.

A novel Fe87Pr11B2 amorphous alloy with outstanding magnetocaloric properties near 325 K

A novel Fe87Pr11B2 metallic glass that exhibits outstanding magnetocaloric effect near room temperature was prepared into the shape of amorphous ribbons. The ribbon exhibits soft magnetic properties and high saturation magnetization at 200 K, which is much lower than its Curie temperature at 325 K. No obvious spin-glass-like behavior was found above 200 K. The almost highest maximum magnetic entropy change (−ΔSmpeak) among Fe-based metallic glasses near the hot end of a residential magnetic refrigerator is most likely attributed to the high concentration of Pr and low content of B in the Fe87Pr11B2 amorphous ribbon. The high −ΔSmpeak, large refrigeration capacity (RC) and adiabatic temperature rise (ΔTad) make the Fe87Pr11B2 amorphous alloy better candidate for the potential component of a refrigerant working in a high-efficiency residential magnetic refrigerator.

Magnetic properties improvement in La0.67Sr0.33MnO3 perovskite powder with praseodymium / nickel doping

Among refrigeration materials, AMnO3 has garnered significant attention due to its unique physical properties, such as the magnetocaloric effect. In this study, we synthesize La0.67Sr0.33-xPrxMn0.975Ni0.025O3 (LSPMNO x=0.05, 0.10, and 0.15) using the sol-gel method. We explored room-temperature refrigeration materials by adjusting the doping levels of Pr ions. All samples, analyzed using XRD, HRTEM, and SAED, exhibit single-phase structures belonging to the R-3c space group. SEM, EDS, and TEM observations revealed that the samples are submicron particles with a uniform distribution of elements. MPMS test results indicate that LSPMNO undergoes a second order magnetic phase transition. With increasing Pr content, the Curie temperature (TC) gradually decreases, while the magnetic entropy change (∆SM) and relative cooling power (RCP) increase. Notably, La0.67Sr0.28Pr0.15Mn0.975Ni0.025O3 achieves an RCP of up to 306.63 J/kg, which is 74.79 % that of Gd.

Envisioning the structural and room temperature impedance spectroscopy study of praseodymium modified lanthanum ferrites

Praseodymium-modified lanthanum ferrites with general formula La1-xPrxFeO3 [x = 0.0, 0.1, 0.3, 0.5] were prepared using the sol-gel auto combustion technique. The X-ray diffraction patterns of all samples supported the orthorhombic crystal structure with the Pbnm space group. With increasing Pr concentration, it was discovered that the average crystallite size dropped from 44.29 to 29.83 nm. An LCR metre was used to evaluate the frequency-dependent dielectric characteristics between 100 Hz and 1 MHz at room temperature. A single semicircle on the Nyquist plots highlights the impact of grain resistance on electrical behaviour. The depressed semicircles at intermediate frequencies might be created by the grain boundary effect, while semicircles depressed at high frequencies imply grain conduction. The dielectric behaviour of lanthanum ferrites is explained based on Koop’s theory. The loss factor resulting from domain wall resonance displayed the same dielectric constant dispersion behaviour. At high frequencies, orthoferrites were shown to have lower dielectric losses. This is due to the constrained motion of the domain wall, which suggests that magnetically tunable filters and oscillators are possible practical uses.