Journal of Magnetism and Magnetic Materials最新文献

Structural, magnetic, and cryogenic magnetocaloric properties of Gd11O10(SiO4)(PO4)3 phosphosilicate Gd11O10(SiO4)(PO4)3磷硅酸盐的结构、磁性和低温磁热性能

IF 2.5 3区材料科学

Journal of Magnetism and Magnetic Materials Pub Date : 2025-04-25 DOI: 10.1016/j.jmmm.2025.173107

Wang Chen, Junli Lin, Xin Wang, Lingwei Li

{"title":"Structural, magnetic, and cryogenic magnetocaloric properties of Gd11O10(SiO4)(PO4)3 phosphosilicate","authors":"Wang Chen, Junli Lin, Xin Wang, Lingwei Li","doi":"10.1016/j.jmmm.2025.173107","DOIUrl":"10.1016/j.jmmm.2025.173107","url":null,"abstract":"<div><div>In this work, we synthesized the Gd<sub>11</sub>O<sub>10</sub>(SiO<sub>4</sub>)(PO<sub>4</sub>)<sub>3</sub> phosphosilicate through high-temperature solid-phase reaction and systematically studied its structure, magnetic properties, and cryogenic magnetocaloric performances. The Gd<sub>11</sub>O<sub>10</sub>(SiO<sub>4</sub>)(PO<sub>4</sub>)<sub>3</sub> is found to crystalize in a triclinic structure (space group <em>P</em>1) and its consistent elements are all distributed uniformly and present as Gd<sup>3+</sup>, Si<sup>4+</sup>, P<sup>5+</sup>, and O<sup>2–</sup> valence states, respectively. Moreover, prominent magnetocaloric performances were observed around its magnetic ordering temperature of 3.1 K. Under 0-7T magnetic field variation, the maximum magnetic entropy change/temperature-averaged magnetic entropy change (5 K-lift) and relative cooling power/refrigerant capacity of Gd<sub>11</sub>O<sub>10</sub>(SiO<sub>4</sub>)(PO<sub>4</sub>)<sub>3</sub> oxide are 33.76/31.42 J/kgK and 389.98/295.15 J/kg, respectively, which are comparable to most acquired <em>RE</em>-based remarkable magnetocaloric materials, making present Gd<sub>11</sub>O<sub>10</sub>(SiO<sub>4</sub>)(PO<sub>4</sub>)<sub>3</sub> phosphosilicate may considerable for cryogenic magnetic refrigeration application.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"626 ","pages":"Article 173107"},"PeriodicalIF":2.5,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143873990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Electronic, optical and magnetic properties of TM-doped CdTe nanosheet: First-principles calculations tm掺杂CdTe纳米片的电子、光学和磁性：第一性原理计算

IF 2.5 3区材料科学

Journal of Magnetism and Magnetic Materials Pub Date : 2025-04-23 DOI: 10.1016/j.jmmm.2025.173079

N.A. Ismayilova , Z.A. Jahangirli

{"title":"Electronic, optical and magnetic properties of TM-doped CdTe nanosheet: First-principles calculations","authors":"N.A. Ismayilova , Z.A. Jahangirli","doi":"10.1016/j.jmmm.2025.173079","DOIUrl":"10.1016/j.jmmm.2025.173079","url":null,"abstract":"<div><div>The electronic, magnetic, and optical properties of two-dimensional (2D) CdTe nanosheets (N.S.) with substitutional doping of transition metal atoms (Cr, Mn, Fe, Co, V, Cu) were investigated using density functional theory (DFT). To determine the stable magnetic phases, the total energies of doped nanosheets were optimized for various ferromagnetic and antiferromagnetic configurations. The findings reveal that, while the pristine nanosheet exhibits a non-magnetic, wide-bandgap (3.28 eV) semiconductor behavior, doping with transition metal atoms induces magnetic moments, leading to structural reconstruction around the dopant and its neighboring atoms. The Cr- and Co-doped CdTe nanosheets, exhibiting 100 % spin polarization, are promising candidates for spintronic devices due to their strong half-metallic ferromagnetic properties. The optical spectra of both pure and transition metal-doped CdTe nanosheets were calculated along the z-axis as a function of wavelength (λ). The computed optical properties include the complex dielectric function and absorption as a function of wavelength. These interesting results suggest that TM-doped CdTe nanosheets hold potential for applications in nanodevices and spintronic devices based on low-dimensional nanostructures.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"626 ","pages":"Article 173079"},"PeriodicalIF":2.5,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143874108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Analysis of Microstructural, Electronic and Magnetic Properties of Nanocrystalline Compound Sm2ZrCo16: Effects of Annealing Temperature and Role of Intergranular Exchange Coupling 纳米晶化合物Sm2ZrCo16的显微组织、电子和磁性能分析：退火温度的影响和晶间交换耦合的作用

IF 2.5 3区材料科学

Journal of Magnetism and Magnetic Materials Pub Date : 2025-04-23 DOI: 10.1016/j.jmmm.2025.173085

R. Fersi , A. Reinhold , A. Pereira , A.P. Dalia

{"title":"Analysis of Microstructural, Electronic and Magnetic Properties of Nanocrystalline Compound Sm2ZrCo16: Effects of Annealing Temperature and Role of Intergranular Exchange Coupling","authors":"R. Fersi , A. Reinhold , A. Pereira , A.P. Dalia","doi":"10.1016/j.jmmm.2025.173085","DOIUrl":"10.1016/j.jmmm.2025.173085","url":null,"abstract":"<div><div>In this study, we investigated the microstructural, electronic, and magnetic properties of nanocrystalline Sm2ZrCo16 alloys. This compound adopts a trigonal structure with a space group P3̅m1 [164] and exhibits a Curie temperature TC of approximately 798 K. Quantitative analysis of the electronic structure, magnetic structure, exchange interactions (Jij), and band structure was performed using Density Functional Theory (DFT) calculations implemented in the Wien2k code. DFT calculations predicted a density of states indicating a pronounced ferromagnetic behavior. The mean-field theory (MFT) method was used to estimate the Curie temperature (T<sub>C</sub>) from the exchange interactions (J<sub>ij</sub>) obtained between different atoms, with an implementation of MFT in a Python code. We analyzed the influence of the annealing temperature (Ta) on the magnetic performances of these samples, with the main objective of identifying the mechanisms responsible for the improvement of the magnetic properties as a function of Ta. An analysis of the intergranular exchange coupling (IGEC) and grain size revealed that the coercivity (HC) reaches a maximum value of 29632 Oe at Ta = 898 K. This improvement is attributed to grain size optimization and enhanced IGEC, which improves magnetic anisotropy and resistance to magnetic domain reversion. However, higher annealing temperatures result in excessive grain growth, leading to a decrease in coercivity (HC). The novelty of this work lies in the precise identification of annealing conditions to maximize the magnetic properties of this compound, while exploring the crucial role of IGEC in these improvements. This research opens new perspectives for the design of high-performance nanostructured magnetic materials based on the Sm2ZrCo16 alloy.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"626 ","pages":"Article 173085"},"PeriodicalIF":2.5,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of plastic damage orientation with respect to magnetic flux pathway on magnetic performance for NGO electrical steel 磁通路径塑性损伤方向对NGO电工钢磁性能的影响

IF 2.5 3区材料科学

Journal of Magnetism and Magnetic Materials Pub Date : 2025-04-23 DOI: 10.1016/j.jmmm.2025.173066

Fanfu Wu, Lei Zhou, Soulard Juliette, Claire Davis

{"title":"Effect of plastic damage orientation with respect to magnetic flux pathway on magnetic performance for NGO electrical steel","authors":"Fanfu Wu, Lei Zhou, Soulard Juliette, Claire Davis","doi":"10.1016/j.jmmm.2025.173066","DOIUrl":"10.1016/j.jmmm.2025.173066","url":null,"abstract":"<div><div>Non-grain-oriented (NGO) electrical steel laminations are used in electric motor stators and rotors and are usually produced by stamping the complex shape from steel strip. It is known that the cut-edge damage, an unavoidable result of this process, adversely affects magnetic properties. During motor operation, magnetic flux flows through these regions, with pathways that may align parallel or perpendicular to the damage. This paper investigates the effect of flux orientation relative to cut-edge damage on the magnetic performance using both experimental measurements and 3D finite element modelling (FEM) for M250-35A NGO electrical steel. A novel tensile test specimen was designed to allow single-sheet tester (SST) samples (300 x 30 x 0.35 mm) to be extracted with comparable plastic damage levels (average 6.2 % strain) but varying orientations to the magnetic flux pathway. FEM simulations, developed in COMSOL Multiphysics, of the SST samples used BH curves for damaged and undamaged material to determine the magnetic behaviour for the SST samples with the different damage orientations. Experimental and modelled results showed consistent trends, revealing that both damage orientations deteriorate the magnetic performance compared to undamaged material, with damage perpendicular to the flux pathway giving more severe degradation. This effect was particularly notable at the BH curve knee point, where the perpendicular damage sample displayed a 20 % lower magnetic flux density than the parallel damage sample. These results highlight that motor performance will be affected not only by the extent of cut-edge damage but also by the design of the laminations through the magnetic flux pathways relative to the cut-edge damage, especially in areas operating below magnetic saturation.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"626 ","pages":"Article 173066"},"PeriodicalIF":2.5,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143877496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Magnetic characteristics of threaded cores with round iron wires in AC magnetic fields 交流磁场中圆形铁线螺纹磁芯的磁特性

IF 2.5 3区材料科学

Journal of Magnetism and Magnetic Materials Pub Date : 2025-04-22 DOI: 10.1016/j.jmmm.2025.173063

Eunchae Jung, Kyungsik Seo, Il Han Park

{"title":"Magnetic characteristics of threaded cores with round iron wires in AC magnetic fields","authors":"Eunchae Jung, Kyungsik Seo, Il Han Park","doi":"10.1016/j.jmmm.2025.173063","DOIUrl":"10.1016/j.jmmm.2025.173063","url":null,"abstract":"<div><div>This study explores the magnetic characteristics of threaded cores constructed with round cross-sectional iron wires, designed to mitigate eddy currents in magnetic devices. The threaded core comprised iron threads separated by an insulating material. Previous studies have demonstrated the remarkable efficacy of threaded cores in reducing eddy currents. These investigations employed iron threads with square cross-sectional structures. However, round cross-sectional wires are more prevalent in industrial applications owing to their productivity, cost-effectiveness, and superior mechanical properties. In this study, numerical and experimental analyses are conducted to examine the characteristics of round-wire threaded cores. In the numerical analysis, we compare the round-wire threaded core with other core types, namely the laminated core and square-wire threaded core, to assess their geometric attributes and magnetic performances. Additionally, further analysis is performed to examine the impact of round wire diameter on the magnetic performance of the threaded cores. The findings obtained from the numerical analysis are verified through experimental testing, which involves lab-made threaded cores using a commercially available round iron wire. This study reveals that round-wire threaded cores offer promising performance in reducing eddy currents, with smaller wire diameters exhibiting superior magnetic properties, particularly in high-frequency applications.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"625 ","pages":"Article 173063"},"PeriodicalIF":2.5,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Unveiling the robustness of half-metallicity under strain effects of CoVYZ (Z = Si, Ge, Sn) alloys 揭示了CoVYZ （Z = Si, Ge, Sn）合金半金属性在应变效应下的鲁棒性

IF 2.5 3区材料科学

Journal of Magnetism and Magnetic Materials Pub Date : 2025-04-21 DOI: 10.1016/j.jmmm.2025.173068

Fareeha Fatima , Atia Atiq , Qura Tul Ain , Farah Andleeb , Altaf Hussain , Muhammad Amir Rafiq , Muhammad Nasir Rasul

{"title":"Unveiling the robustness of half-metallicity under strain effects of CoVYZ (Z = Si, Ge, Sn) alloys","authors":"Fareeha Fatima , Atia Atiq , Qura Tul Ain , Farah Andleeb , Altaf Hussain , Muhammad Amir Rafiq , Muhammad Nasir Rasul","doi":"10.1016/j.jmmm.2025.173068","DOIUrl":"10.1016/j.jmmm.2025.173068","url":null,"abstract":"<div><div>Based on density functional theory computations, a systematic analysis has been conducted to elucidate the physical attributes of CoVYZ (Z = Si, Ge, Sn) alloys. To treat the exchange and correlation effects, generalized gradient approximation has been incorporated using WIEN2k package. The structural characteristics assure that CoVYZ alloys are comparatively stable in magnetic phase and electronic properties reveal that these alloys are half-metallic. The band character spectra of CoVYZ alloys signify that the Fermi level is predominantly influenced by the dt<sub>2g</sub> bands of Co-atom. The calculated values of total magnetic moment found to be µ<sub>total=</sub> 3.0 <span><math><mrow><msub><mi>μ</mi><mi>B</mi></msub><mo>/</mo><mi>f</mi><mo>.</mo><mi>u</mi><mo>,</mo></mrow></math></span> pointing the Slater-Pauling rule, (<span><math><mrow><msub><mi>M</mi><mrow><mi>SPR</mi></mrow></msub><mo>=</mo><msub><mi>N</mi><mi>v</mi></msub><mrow><mo>-</mo><mn>24</mn><mo>)</mo></mrow><msub><mi>μ</mi><mrow><mi>B</mi><mo>.</mo></mrow></msub></mrow></math></span> In CoVYZ (Z = Si, Sn) alloys, Co exhibits ferrimagnetic coupling under specific strains: +1% to + 5 % for CoVYSi and at + 1 % for CoVYSn. At negative strains, a shift from antiferromagnetism to ferrimagnetism occurs with respect to the V atom: at −5% for Si, −7% for Ge and −10 % for Sn. The effect of uniform strain specifically on the electronic and magnetic characteristics revealed that half-metallicity sustain upto expansion (+6%<strong>@</strong> a<sub>o</sub>) and upto contraction (−13 %@ a<sub>o</sub>) distinctly. The CoVYSn alloy found most robust, rendering its suitability for spintronic applications under harsh environment.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"626 ","pages":"Article 173068"},"PeriodicalIF":2.5,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143864164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Origin of weak ferromagnetism in Ti doped Bi0.9Nd0.1FeO3 ceramics Ti掺杂Bi0.9Nd0.1FeO3陶瓷弱铁磁性的来源

IF 2.5 3区材料科学

Journal of Magnetism and Magnetic Materials Pub Date : 2025-04-21 DOI: 10.1016/j.jmmm.2025.173091

N.M. Hung , Q.N. Pham , T.Q. Hung , N.T.B. Yen , E. Riviere , N.T.M. Hong , T. Bongkarn , B.D. Nhi , D.V. Karpinsky , V.D. Binh , P.T. Tho , N.D. Long

{"title":"Origin of weak ferromagnetism in Ti doped Bi0.9Nd0.1FeO3 ceramics","authors":"N.M. Hung , Q.N. Pham , T.Q. Hung , N.T.B. Yen , E. Riviere , N.T.M. Hong , T. Bongkarn , B.D. Nhi , D.V. Karpinsky , V.D. Binh , P.T. Tho , N.D. Long","doi":"10.1016/j.jmmm.2025.173091","DOIUrl":"10.1016/j.jmmm.2025.173091","url":null,"abstract":"<div><div>The crystal structure, structural phase formation, ionic oxidation state and magnetic properties were studied for understanding the weak ferromagnetism of Ti doped Bi<sub>0.9</sub>Nd<sub>0.1</sub>FeO<sub>3</sub> compounds in the 10–400 K temperature range. The crystal structure analysis performed by X-ray diffraction and Raman scattering revealed a distorted rhombohedral structure in Ti-doped samples. X-ray photoelectron spectroscopy identified a significant fraction of oxygen vacancies (∼5 %) and about 38 % of Fe<sup>2+</sup> ions content which are the primary factors leading to a notable structural distortion. Magnetic measurements revealed the weak magnetic behavior in a wide temperature range. These observations have approved that titanium substitution is very effective tool to unlock the weak ferromagnetism; a mechanism responsible for the observed results is discussed in the context of lattice distortion, oxygen deficiency, and complex oxidation state of Fe ions. The release of a weak net magnetization in Ti-doped compounds is mainly caused by a disturbance of long-range incommensurate spin-cycloidal structure.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"625 ","pages":"Article 173091"},"PeriodicalIF":2.5,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143864405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Interplay between interfacial Dzyaloshinskii–Moriya interaction and magnetic anisotropy in 4d transition metal multilayers for skyrmion nucleation 四维过渡金属多层膜中Dzyaloshinskii-Moriya相互作用与磁各向异性对skyrmion成核的影响

IF 2.5 3区材料科学

Journal of Magnetism and Magnetic Materials Pub Date : 2025-04-21 DOI: 10.1016/j.jmmm.2025.173036

Tamali Mukherjee , Banasree Sadhukhan , V. Satya Narayana Murthy

{"title":"Interplay between interfacial Dzyaloshinskii–Moriya interaction and magnetic anisotropy in 4d transition metal multilayers for skyrmion nucleation","authors":"Tamali Mukherjee , Banasree Sadhukhan , V. Satya Narayana Murthy","doi":"10.1016/j.jmmm.2025.173036","DOIUrl":"10.1016/j.jmmm.2025.173036","url":null,"abstract":"<div><div>Skyrmions refer to small swirling spin structures that emerge in ferromagnetic materials and show promising features to be used as a ‘bit’ of information in future spintronic devices. Our research explores the possibility of nucleating skyrmions in X–Fe/Ir(111) multilayer nano-structure where, X is one of the 4d transition metals, such as, Pd, Rh, Ru, Mo and Nb. The resulting final state is determined by the competition between the frustrated exchange interaction, primarily contributed by the top 4d transition metal layer, and the Dzyaloshinskii–Moriya interactions induced significantly by the 5d heavy metal Ir(111) layer. We apply a perpendicular dc magnetic field to the nano-structure and observe gradual phase transformation from the spin spiral ground state to a stable relaxed state of nano-scale skyrmions. A proper choice of magnetic anisotropy and interfacial Dzyaloshinskii–Moriya interaction leads to a range of external magnetic fields essential for the existence and stability of skyrmions. By raising the temperature, we assess the thermal stability of the nucleated skyrmions to evaluate their potential as information carriers in future spintronic devices.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"625 ","pages":"Article 173036"},"PeriodicalIF":2.5,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143864403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Indications of quantum fluctuations in magnetically frustrated Gd2GaSbO7 and Gd2InSbO7 pyrochlores 磁阻Gd2GaSbO7和Gd2InSbO7焦绿石的量子涨落迹象

IF 2.5 3区材料科学

Journal of Magnetism and Magnetic Materials Pub Date : 2025-04-20 DOI: 10.1016/j.jmmm.2025.173088

Nallamuthu Sengodan , Andrea Dzubinska , K. Arun , A.R. Vimaljith , R. Nagalakshmi , Ivan Čurlik , Sergej Iľkovič , Marian Reiffers

{"title":"Indications of quantum fluctuations in magnetically frustrated Gd2GaSbO7 and Gd2InSbO7 pyrochlores","authors":"Nallamuthu Sengodan , Andrea Dzubinska , K. Arun , A.R. Vimaljith , R. Nagalakshmi , Ivan Čurlik , Sergej Iľkovič , Marian Reiffers","doi":"10.1016/j.jmmm.2025.173088","DOIUrl":"10.1016/j.jmmm.2025.173088","url":null,"abstract":"<div><div>Gd<sub>2</sub>GaSbO<sub>7</sub> (GGSO) and Gd<sub>2</sub>InSbO<sub>7</sub> (GISO) pyrochlore compounds are investigated as potential candidates for exhibiting quantum fluctuations in a spin-ice-like state. These materials, less explored in magnetic frustration, were synthesized and structurally confirmed via X-ray diffraction. Magnetic and heat capacity measurements revealed no long-range order down to 400 mK. The low-temperature magnetic heat capacity shows broad maxima around T<sub>max</sub> = 0.9 K and T<sub>max</sub> = 1 K for GGSO and GISO respectively, with power-law dependence <span><math><mfenced><mrow><msub><mi>C</mi><mrow><mi>mag</mi></mrow></msub><mo>≈</mo><msup><mrow><mi>T</mi></mrow><mrow><mi>d</mi><mo>/</mo><mi>n</mi></mrow></msup></mrow></mfenced></math></span> yielding exponents, T<sup>1.71</sup> for GGSO and T<sup>1.49</sup> for GISO, indicating spin fluctuations at low temperatures. GGSO and GISO retain residual entropy akin to water ice, indicative of spin-ice behavior. Notably, GISO has the weakest exchange interaction among Gd-based pyrochlores, which may be influenced by chemical pressure and exchange pathways. These findings highlight significant spin fluctuations and potential quantum effects, contrasting with long-range order in other Gd-pyrochlores and aligning with quantum spin-ice candidates like Pr<sub>2</sub>Zr<sub>2</sub>O<sub>7</sub> and Yb<sub>2</sub>GaSbO<sub>7</sub>.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"626 ","pages":"Article 173088"},"PeriodicalIF":2.5,"publicationDate":"2025-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143864165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Investigations on physicochemical, magnetic and photocatalytic properties of magnetite-rich stones from Palakkad Gap, Western Ghats, India 印度西高止山帕拉卡德峡谷富磁铁矿的物理化学、磁性和光催化特性研究

IF 2.5 3区材料科学

Journal of Magnetism and Magnetic Materials Pub Date : 2025-04-20 DOI: 10.1016/j.jmmm.2025.173090

Nithyananda Suman, Senthil Karuppanan

{"title":"Investigations on physicochemical, magnetic and photocatalytic properties of magnetite-rich stones from Palakkad Gap, Western Ghats, India","authors":"Nithyananda Suman, Senthil Karuppanan","doi":"10.1016/j.jmmm.2025.173090","DOIUrl":"10.1016/j.jmmm.2025.173090","url":null,"abstract":"<div><div>The southern side of Palakkad Gap, a region in the Western Ghats, India, is observed to have an abundance of rocks and stones that exhibit magnetic attraction. This study investigates the physicochemical, photocatalytic, and magnetic properties of the magnetite separated from such stones collected from the Palakkad Gap in an environmentally friendly manner. The collected stones were powdered, and the magnetite was separated using a magnet and purified. Characterization using X-ray diffraction (XRD) confirmed the presence of magnetite, while Thermogravimetric Analysis (TGA) demonstrated its thermal stability at lower temperatures. The Energy Dispersive X-ray (EDX) analysis identified the elements, which included carbon, magnesium, aluminium, silica, potassium, titanium, iron, and cobalt. Following magnetic separation, iron and oxygen were found to be the dominant elements. The magnetite material’s surface morphology and optical characteristics were further examined using Field Emission Scanning Electron Microscopy (FESEM), Photoluminescence (PL), and Ultraviolet–Visible Spectroscopy (UV), with the UV analysis estimating a direct band gap energy of 2.04 eV. Vibrating Sample Magnetometer (VSM) measurements revealed strong ferrimagnetic properties of the magnetite sample. The photocatalytic efficiency of the magnetite was assessed through the degradation of dyes such as Congo red (CR), Methyl orange (MO), and Methylene blue (MB). The results indicate high degradation efficiencies of 96.74 % for MB, 97.21 % for MO, and 98.99 % for CR within 2 h under visible light with excellent recyclability in natural conditions. Furthermore, the possibility of reusing the treated dye solutions was evaluated by conducting <em>Vigna radiata</em> seed germination tests. The tests demonstrated significant seed growth, suggesting the degraded dye solutions were non-toxic and suitable for potential agricultural applications.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"626 ","pages":"Article 173090"},"PeriodicalIF":2.5,"publicationDate":"2025-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143873987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0