{"title":"Room-Temperature Ferromagnetism in ZnTe Nanosheet Doped by Transition Metal Atom","authors":"Narmin A. Ismayilova","doi":"10.1007/s10948-025-06920-z","DOIUrl":"10.1007/s10948-025-06920-z","url":null,"abstract":"<div><p>To investigate the potential functionalities of transition metal atom (V, Cr, Mn, Fe, Co, and Cu)-doped ZnTe nanosheets in nanoscale science and spintronic applications, we conducted spin-polarized density functional theory calculations. This study focused on doping at various concentrations of transition metal atoms, with the Zn edge which was the substitution position. The pristine ZnTe nanosheet is intrinsically nonmagnetic; however, the introduction of transition metal atoms induces spontaneous spin polarization, resulting in a significant magnetic moment. Electronic structure calculations reveal distinct conducting behaviors—semiconducting and half-metallic—depending on the concentration of the dopant atoms. Furthermore, the calculated Curie temperature, obtained through mean-field approximation, indicates values exceeding room temperature for all concentrations of V, Cr, Fe, and Cu, with an increasing trend as the concentration of transition metal atoms rises. These findings suggest that Cr-, Fe-, and Cu-doped ZnTe nanosheets may be good candidates for spintronic applications due to their ferromagnetism and high Curie temperatures.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"38 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143361944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lihui Sun, Xinhui Lv, Yi Xu, Lin Xue, Yongjia Zhang
{"title":"Manipulating the Magnetic Characteristics of Defective SrTiO3 (001) Surfaces Through O2 Adsorption: An Investigation via Hybrid Functional Calculations","authors":"Lihui Sun, Xinhui Lv, Yi Xu, Lin Xue, Yongjia Zhang","doi":"10.1007/s10948-025-06926-7","DOIUrl":"10.1007/s10948-025-06926-7","url":null,"abstract":"<div><p>The electronic and magnetic properties of defective SrTiO<sub>3</sub> (001) surfaces were examined through hybrid functional calculations, focusing on the impact of O<sub>2</sub> adsorption. Among the various vacancy types considered—oxygen vacancy (V<sub>O</sub>), titanium vacancy (V<sub>Ti</sub>), strontium vacancy (V<sub>Sr</sub>), V<sub>Ti</sub> + V<sub>O</sub> complex (V<sub>Ti-O</sub>), and V<sub>Sr</sub> + V<sub>O</sub> complex (V<sub>Sr-O</sub>)—only V<sub>O</sub>, V<sub>Ti</sub>, and V<sub>Ti-O</sub> exhibit magnetic moments. At low O<sub>2</sub> coverage, the adsorption of a single O<sub>2</sub> molecule onto each defective surface results in a reduction of the magnetic moments for surfaces with V<sub>O</sub>, V<sub>Ti</sub>, or V<sub>Ti-O</sub>, potentially decreasing to zero. In contrast, the magnetic moment of surfaces with V<sub>Sr-O</sub> increases from zero to 2 <i>μ</i><sub>B</sub>. Upon the addition of a second O<sub>2</sub> molecule at high O<sub>2</sub> coverage, the magnetic moments of surfaces with V<sub>O</sub> and V<sub>Ti</sub> are significantly enhanced, attributed to the polarization of the p electrons of the two adsorbed O<sub>2</sub> molecules. Surfaces with V<sub>Ti-O</sub> or V<sub>Sr-O</sub> complex defects do not adsorb additional O<sub>2</sub> molecules, and surfaces with V<sub>Sr</sub> are unable to adsorb O<sub>2</sub> molecules. The variation in magnetic moments for the defective surfaces is correlated with the number of electrons acquired by the adsorbed O<sub>2</sub> molecules.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"38 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143361945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Geometric Phase in Kitaev Quantum Spin Liquid","authors":"Zheng-Chuan Wang","doi":"10.1007/s10948-025-06919-6","DOIUrl":"10.1007/s10948-025-06919-6","url":null,"abstract":"<div><p>Quantum spin liquid has massive many-spin entanglement in the ground state; we can evaluate it by the entanglement entropy, but the latter cannot be observed directly by experiment. In this manuscript, we try to characterize its topological properties by the geometric phase. As we know, the usual adiabatic or non-adiabatic geometric phase cannot appear in the density matrix of entanglement entropy, so we extend it to the sub-geometric phase which can exist in the density matrix and have influence on the entanglement entropy, spin correlation function as well as other physical observable. We will demonstrate that the imaginary part of sub-geometric phase can deviate the resonance peak by an amount concerning with this phase and affect the energy level crossing, while the real part of sub-geometric phase may determine the stability of initial state, it may provide a complement on the selection rule of quantum transition.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"38 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143184603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Khalil El Achi, Samih Isber, Malek Tabbal, Mohammad Haidar
{"title":"Probing Magnetic Characteristics of (Co_{60}Fe_{40}) Films Prepared by Pulsed Laser Deposition","authors":"Khalil El Achi, Samih Isber, Malek Tabbal, Mohammad Haidar","doi":"10.1007/s10948-025-06922-x","DOIUrl":"10.1007/s10948-025-06922-x","url":null,"abstract":"<div><p>In this work, we study the magnetic properties of <span>(Co_{60}Fe_{40})</span> films grown by the pulsed laser deposition technique while varying the deposition parameters, specifically the deposition temperature and laser energy. The magnetodynamics of the films including the magnetization (<i>M</i>) and the Gilbert damping (<span>(alpha )</span>) were measured via broadband ferromagnetic measurement. We identify an optimal deposition temperature of approximately 373 K, resulting in high <i>M</i> of 1.54 T and low <span>(alpha )</span> of 0.017 . for a 19 nm thick film. Furthermore, the laser energy variation leads to thicknesses between 5 and 19 nm, with <i>M</i> decreasing linearly with the reduced thickness. This allows the separation of bulk and surface contributions, measuring a bulk magnetization of 1.73 T and a magnetic surface anisotropy of 2.9 . <span>(mJ/m^2)</span> originating from the interfaces. In contrast, we measure an increase in <span>(alpha )</span> with decreasing thickness, emphasizing significant surface contributions.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"38 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143184604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Impact of Cr Insertion Layer on Spin Transport Properties in Co2FeAl/Ta System","authors":"Rohiteswar Mondal, Vidya Alman, Arabinda Haldar, Chandrasekhar Murapaka","doi":"10.1007/s10948-025-06914-x","DOIUrl":"10.1007/s10948-025-06914-x","url":null,"abstract":"<div><p>Spin pumping is recognized as a cogent method for the generation and injection of spin current from ferromagnetic (FM) to nonmagnetic (NM) (FM/NM) layer. The interface at FM/NM layers plays a vital role in spin transport. In this work, we have systematically investigated the effect of Cr interlayer (IL) thickness on the spin transport in Co<sub>2</sub>FeAl(CFA)/Cr/Ta system. We have observed enhancement in the damping parameter with a 2 nm Cr spacer compared to the sample without a spacer layer. The relative spin-mixing conductance in the system is 1.4 times higher in the sample with a spacer layer compared to the reference sample. This is further supported by inverse spin Hall effect measurements. The relative weight of the symmetric to asymmetric component of voltage drop infers the IL dependency of the system. Our study signifies a novel approach to enhance the spin current transport across CFA/Ta system by strategically inserting the Cr interlayer henceforth offering a pathway for improving the efficiency and performance of spintronics devices.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"38 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Current-Phase Relation for Transparent Superconducting Junctions","authors":"Artem V. Galaktionov, Andrei D. Zaikin","doi":"10.1007/s10948-025-06916-9","DOIUrl":"10.1007/s10948-025-06916-9","url":null,"abstract":"<div><p>We present a detailed numerical analysis of a non-equilibrium current-phase relation for transparent Josephson junctions in the voltage-biased regime. In the limit of subgap voltages and temperatures, we demonstrate an important role of phase-periodic dissipative effects which significantly modify the current-phase relation for such superconducting weak links.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"38 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Memory Function of a Three-Dimensional Holstein-Like System","authors":"Zoran Rukelj, Danko Radić, Ivan Kupčić","doi":"10.1007/s10948-025-06911-0","DOIUrl":"10.1007/s10948-025-06911-0","url":null,"abstract":"<div><p>We investigate the zero-temperature electron–phonon memory function of a three-dimensional Holstein-like system with the free electron-like bands. The memory function is a complex function of the incoming photon energy, and it describes the effect of electron–phonon scattering in the dynamical conductivity. In the presented approach, memory function is of the second order in electron–phonon interaction with the amplitude connected to the internal energy scales of the electron–phonon system and with imaginary and real part being connected by Kramers-Kronig relations. A closed-form expression is provided for the imaginary part of the memory function in the case when finite bandwidth, Fermi energy, and optical phonon energy are comparable to one another with several of its features closely investigated. Similarly, we analyze the properties of the real part of the memory function in a closed form whose main features are traced back to the properties of the imaginary part.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"38 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143110072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Investigation of the Effect of Low Purity Boron on the Critical Properties of L-IMD MgB2 Wires","authors":"Ö. Çiçek","doi":"10.1007/s10948-025-06917-8","DOIUrl":"10.1007/s10948-025-06917-8","url":null,"abstract":"<div><p>MgB<sub>2</sub>/Fe superconducting wires were synthesized by sintering at 850 °C for 2 h using low purity B source by using the Localized Internal Mg Diffusion (LIMD) technique, a type of powder-in-tube method. The formation of locally dense MgB<sub>2</sub> regions was targeted with the LIMD technique. In the phase examination of the products by X-ray diffraction, the main phase was determined to be MgB<sub>2</sub>. Lattice parameters and MgO fraction were determined by the Rietveld refinement process. Microscope and scanning electron microscope images revealed that the core parts contained thin and long structures. Magnetic measurements showed that they exhibited a sharp transition interval, and the magnetic critical current density calculated with the Bean Model was in the order of 10<sup>5</sup> A/cm<sup>2</sup>. Pinning force analysis showed that the surface pinning mechanism of the samples was the dominant mechanism. Electrical transport measurements were made using short core samples, and the best resistivity value was obtained in the sample using 86 wt% B source. The transport critical current density values obtained from transport measurements made with long samples at 4.2 K were found to be comparable with the literature. Among the purity levels of 86 wt% and 95 wt% examined in this study, the results of the sample using 86% purity boron were found to be partially improved.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"38 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Hole-Polarons and Bipolarons in the Extended t − J − V Holstein Model","authors":"Srijani Ghosh, Krishanu Roy, Nanda Kumar Ghosh, Subhadip Nath","doi":"10.1007/s10948-025-06909-8","DOIUrl":"10.1007/s10948-025-06909-8","url":null,"abstract":"<div><p>The Holstein t-J model extended by the nearest-neighbor (NN) hole-phonon (h − ph) interaction (<span>(lambda _2)</span>) and inter-site Coulomb repulsion (V/t) is studied using the exact diagonalization method in the context of high-temperature superconducting cuprates. The exotic physics, characteristics, and stability of polarons and bipolarons are explored. Polarons, large hole bipolarons (LHBP), and Small Hole Bipolarons (SHBP) exist in the Holstein t-J model, depending on the relative strength of the h − ph interaction and inter-site Coulomb repulsion. The role of V/t is to suppress the formation of these hole bipolarons. The transition region from polarons to different types of bipolarons’ is shifted to higher magnitudes of <span>(lambda _2)</span> with the increasing strength of intersite Coulomb repulsion. Moreover, increased phonon energy generally induces the formation of bipolarons. A schematic phase diagram is presented. A single peak in specific heat is observed in the accessible temperature range rising due to charge fluctuations. At low temperatures, the system becomes more ordered above the critical value of <span>(lambda _2)</span> in the anti-adiabatic limit.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"38 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Tailoring Optical and Magnetic Properties in Mn2+-Substituted 2D Magnetic Semiconductor SnS2: A Powder XRD Approach for Electronic Structure Analysis","authors":"N. Pavithra, M. Charles Robert","doi":"10.1007/s10948-025-06908-9","DOIUrl":"10.1007/s10948-025-06908-9","url":null,"abstract":"<div><p>A single-phase, two-dimensional layered semiconductor of Mn<sup>2+</sup>-substituted SnS<sub>2</sub> was synthesized using the low temperature and cost-effective hydrothermal method. Powder X-ray diffraction (XRD) analysis revealed a considerable contribution of γ-MnO<sub>2</sub> at higher Mn<sup>2+</sup> substitution concentrations. An XRD blue shift accounts for Mn<sup>2+</sup> substitutions at both substitutional and interstitial sites. Scanning electron microscope (SEM) analysis confirms a two-dimensional disk morphology, containing a large number of nano-crystallites. The electronic structure is visualized using the 3D, 2D, and 1D maximum entropy method (MEM) analysis, such as electron density inside the unit cell, the type and strength of inter- and intra-bonding, and its effect on Mn<sup>2+</sup> substitution. In addition to substitutional doping, MEM-based peak search analysis and electron paramagnetic resonance (EPR) studies confirmed interstitial charge accumulation. The 3% Mn<sup>2+</sup>-substituted composition has superior soft ferromagnetism, with a magnetic saturation of 0.1915 emu/g and coercivity of 174.16 Oe, making it suitable for dilute magnetic semiconductor applications. The mechanism and origin of ferromagnetism are explained based on Mn<sup>2+</sup> substitution in substitutional or interstitial sites as well as the concentration of impurity addition γ-MnO<sub>2</sub>. Optical energy band gap analysis confirms that direct energy gaps are useful for photoactivated catalytic applications. An empirical correlation between magnetic saturation and MEM-based electronic structure is the highlight of the research.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"38 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}