Pub Date : 2024-09-13DOI: 10.1016/j.physb.2024.416517
This study focuses on comprehensively investigating the crystal structure, electronic, magnetic and optical properties of pure and Pb-doped CdS at different concentrations using first-principles methods with the GGA-PBE+U approximation. Our calculations successfully reproduce the experimentally observed optimized lattice parameters and band gap values for both pure and Pb-doped CdS systems. Band structure results show a large and significant reduction in the band gap of Pb-doped CdS at low concentrations, followed by a steady increase at high Pb concentrations. The electron density distribution show the covalent nature between Cd-S and Pb-S. The optical properties of pur and Pb-doped CdS show: a significant increase in absorption and in reflectivity in the visible and ultraviolet domains with doping. Finally, a reduction in optical transmission in the visible energy domain. These optical analyzes provide essential information on the behavior of these materials, thus broadening its practical applications, notably in the design of optoelectronic devices.
{"title":"Investigating the effect of Pb doping on the structural, electronic, magnetic, and optical properties of wurtzite CdS","authors":"","doi":"10.1016/j.physb.2024.416517","DOIUrl":"10.1016/j.physb.2024.416517","url":null,"abstract":"<div><p>This study focuses on comprehensively investigating the crystal structure, electronic, magnetic and optical properties of pure and Pb-doped CdS at different concentrations using first-principles methods with the GGA-PBE+U approximation. Our calculations successfully reproduce the experimentally observed optimized lattice parameters and band gap values for both pure and Pb-doped CdS systems. Band structure results show a large and significant reduction in the band gap of Pb-doped CdS at low concentrations, followed by a steady increase at high Pb concentrations. The electron density distribution show the covalent nature between Cd-S and Pb-S. The optical properties of pur and Pb-doped CdS show: a significant increase in absorption and in reflectivity in the visible and ultraviolet domains with doping. Finally, a reduction in optical transmission in the visible energy domain. These optical analyzes provide essential information on the behavior of these materials, thus broadening its practical applications, notably in the design of optoelectronic devices.</p></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142240502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2024-09-13DOI: 10.1016/j.physb.2024.416537
This study investigates the superconducting and magnetic behaviour of Potassium-doped Cu0.5Tl0.5Ba2Ca2Cu3-xKxO10-δ superconductors by varying potassium-concentrations (x = 0, 1, 2.5, 3). We have synthesized the samples by two-step solid-state-reaction method and explored their superconducting features by XRD analysis, SEM and resistivity measurements. Through a comprehensive exploration of magnetic measurements i.e magnetization versus magnetic field and temperature, we aim to elucidate the impact of potassium doping on the diamagnetic characteristics of these superconductors. The results reveal that by raising the doping concentration of potassium, the orthorhombic unit cell's axis lengths decresese. The onset of superconductivity and the magnitude of diamagnetism are also decreased. The magnetic behavior of these samples was studied by field cooled and zero field cooled from 2 to 300 K and taking the hysteresis loops at temperatures 2 to 60 K. In the doped samples, the suppression of current density is steeper with increase in temperature. Doped atoms boost the population of localized defects, which serve as pinning centers. This study will contribute valuable information to the understanding of the relationship between magnetic behavior and the superconducting nature of complex oxide materials.
{"title":"Exploring the magnetic behavior of potassium-doped Cu0.5Tl0.5Ba2Ca2Cu3-xKxO10-δ (x=0, 1, 2.5, 3) superconductors","authors":"","doi":"10.1016/j.physb.2024.416537","DOIUrl":"10.1016/j.physb.2024.416537","url":null,"abstract":"<div><p>This study investigates the superconducting and magnetic behaviour of Potassium-doped Cu<sub>0.5</sub>Tl<sub>0.5</sub>Ba<sub>2</sub>Ca<sub>2</sub>Cu<sub>3-x</sub>K<sub>x</sub>O<sub>10-δ</sub> superconductors by varying potassium-concentrations (x = 0, 1, 2.5, 3). We have synthesized the samples by two-step solid-state-reaction method and explored their superconducting features by XRD analysis, SEM and resistivity measurements. Through a comprehensive exploration of magnetic measurements i.e magnetization versus magnetic field and temperature, we aim to elucidate the impact of potassium doping on the diamagnetic characteristics of these superconductors. The results reveal that by raising the doping concentration of potassium, the orthorhombic unit cell's axis lengths decresese. The onset of superconductivity and the magnitude of diamagnetism are also decreased. The magnetic behavior of these samples was studied by field cooled and zero field cooled from 2 to 300 K and taking the hysteresis loops at temperatures 2 to 60 K. In the doped samples, the suppression of current density is steeper with increase in temperature. Doped atoms boost the population of localized defects, which serve as pinning centers. This study will contribute valuable information to the understanding of the relationship between magnetic behavior and the superconducting nature of complex oxide materials.</p></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142232567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2024-09-12DOI: 10.1016/j.physb.2024.416476
In this paper, we comprehensively investigate the isothermal magnetization behavior of doped perovskite manganite nanoparticles. The focus is on understanding the impact of variation of particle sizes on the soft and hard magnetic phases with respect to the changes in the coercive field and remanent magnetization, both theoretically and experimentally. The study seeks to correlate experimental findings with the proposed phenomenological model to gain deeper insights into the underlying mechanisms governing exchange coupling and anisotropy effects in the nanocrystalline composites. The proposed phenomenological model beautifully demonstrates how the values of saturation magnetization and coercive field changes with changing the particle size in the nanocrystalline La0.48Ca0.52MnO (LCMO48) and La0.46Ca0.54MnO (LCMO46) compounds. In addition, the model provide an insights into the limitations of critical radius, size and shape of the nanocrystalline particle. This investigation looks into how the size of particles affects their magnetic properties, specifically coercive field and remanent magnetization.
{"title":"Magnetic exchange coupled composite behavior in the doped manganite nanoparticles: A proposed phenomenological model","authors":"","doi":"10.1016/j.physb.2024.416476","DOIUrl":"10.1016/j.physb.2024.416476","url":null,"abstract":"<div><p>In this paper, we comprehensively investigate the isothermal magnetization behavior of doped perovskite manganite nanoparticles. The focus is on understanding the impact of variation of particle sizes on the soft and hard magnetic phases with respect to the changes in the coercive field and remanent magnetization, both theoretically and experimentally. The study seeks to correlate experimental findings with the proposed phenomenological model to gain deeper insights into the underlying mechanisms governing exchange coupling and anisotropy effects in the nanocrystalline composites. The proposed phenomenological model beautifully demonstrates how the values of saturation magnetization and coercive field changes with changing the particle size in the nanocrystalline La<sub>0.48</sub>Ca<sub>0.52</sub>MnO<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> (LCMO48) and La<sub>0.46</sub>Ca<sub>0.54</sub>MnO<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> (LCMO46) compounds. In addition, the model provide an insights into the limitations of critical radius, size and shape of the nanocrystalline particle. This investigation looks into how the size of particles affects their magnetic properties, specifically coercive field and remanent magnetization.</p></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142230625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2024-09-12DOI: 10.1016/j.physb.2024.416542
The inverse spin Hall effect (ISHE) is a significant phenomenon that enables the conversion of spin current into charge current, offering promising applications in novel spintronic devices. In conventional ISHE measurements, it is widely recognized that the spin polarization, spin current, and generated charge current are mutually perpendicular. This study systematically investigates the ISHE in Pt/Co/Pt multilayers grown on a single-crystalline yttrium iron garnet (YIG) layer. A non-zero ISHE voltage was obtained along the direction parallel to the external magnetic field within the YIG coercive field range, deviating from the classical ISHE behavior. Our investigation revealed that the in-plane magnetic anisotropy of single-crystalline YIG plays a crucial role, as the easy axis of YIG and the external magnetic field collaboratively determine the polarization direction of the spin current, especially when the external magnetic field is smaller than the YIG coercive force. Furthermore, by tuning the small in-plane magnetization component of the Pt/Co/Pt multilayers, which couples with the YIG magnetization, we were able to control the shape and reversal path of the ISHE voltage loop. These findings deepen our understanding of how magnetic order affects charge current flow in ISHE measurements. The variety of ISHE voltage loop shapes and reversal paths observed suggest potential applications for this device as a magnetic field sensor.
{"title":"Unusual inverse spin Hall effect in Pt/Co/Pt multilayers on single-crystalline YIG","authors":"","doi":"10.1016/j.physb.2024.416542","DOIUrl":"10.1016/j.physb.2024.416542","url":null,"abstract":"<div><p>The inverse spin Hall effect (ISHE) is a significant phenomenon that enables the conversion of spin current into charge current, offering promising applications in novel spintronic devices. In conventional ISHE measurements, it is widely recognized that the spin polarization, spin current, and generated charge current are mutually perpendicular. This study systematically investigates the ISHE in Pt/Co/Pt multilayers grown on a single-crystalline yttrium iron garnet (YIG) layer. A non-zero ISHE voltage was obtained along the direction parallel to the external magnetic field within the YIG coercive field range, deviating from the classical ISHE behavior. Our investigation revealed that the in-plane magnetic anisotropy of single-crystalline YIG plays a crucial role, as the easy axis of YIG and the external magnetic field collaboratively determine the polarization direction of the spin current, especially when the external magnetic field is smaller than the YIG coercive force. Furthermore, by tuning the small in-plane magnetization component of the Pt/Co/Pt multilayers, which couples with the YIG magnetization, we were able to control the shape and reversal path of the ISHE voltage loop. These findings deepen our understanding of how magnetic order affects charge current flow in ISHE measurements. The variety of ISHE voltage loop shapes and reversal paths observed suggest potential applications for this device as a magnetic field sensor.</p></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142270328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2024-09-12DOI: 10.1016/j.physb.2024.416522
A series of novel single phased Eu3+ doped BaZr(PO4)2 phosphor were synthesized employing simple solid-state reaction route and studied the influence of different chlorides as fluxes (NH4Cl, KCl, LiCl and NaCl) on structural and photoluminescence properties. The structural characterization reveals pure phase formation of the as prepared phosphors with monoclinic crystal structure. The photoluminescence (PL) spectra recorded under 392 nm excitation depicts intense emission at 612 nm. Further, the concentration of Eu3+ ion was well tuned by carefully studying the PL spectra and the optimised amount of Eu3+ ion in BaZr(PO4)2 is found to be 3.0 mol%. The luminescence properties of phosphor with added aforementioned fluxes were also studied in detail. NH4Cl was found to be the best among all the fluxes taken and the photoluminescence intensity of phosphor gets enhanced by 1.43 times of without flux. The Judd-Ofelt theory was employed for determination of spectral parameters from photoluminescent emission spectra. The temperature dependent photoluminescent studies establishes stability of phosphor emission at operating temperatures. The CIE coordinates were evaluated that confirms the pure red emission under n-UV excitation. All the studies indicate the potential of the said phosphor in phosphor converted white light emitting diodes as red emitter and indoor lighting.
{"title":"Optical characteristics, Judd-Ofelt analysis of enhanced luminescence by flux in thermally stable, novel Eu3+- doped BaZr(PO4)2 phosphor for indoor lighting applications","authors":"","doi":"10.1016/j.physb.2024.416522","DOIUrl":"10.1016/j.physb.2024.416522","url":null,"abstract":"<div><p>A series of novel single phased Eu<sup>3+</sup> doped BaZr(PO<sub>4</sub>)<sub>2</sub> phosphor were synthesized employing simple solid-state reaction route and studied the influence of different chlorides as fluxes (NH<sub>4</sub>Cl, KCl, LiCl and NaCl) on structural and photoluminescence properties. The structural characterization reveals pure phase formation of the as prepared phosphors with monoclinic crystal structure. The photoluminescence (PL) spectra recorded under 392 nm excitation depicts intense emission at 612 nm. Further, the concentration of Eu<sup>3+</sup> ion was well tuned by carefully studying the PL spectra and the optimised amount of Eu<sup>3+</sup> ion in BaZr(PO<sub>4</sub>)<sub>2</sub> is found to be 3.0 mol%. The luminescence properties of phosphor with added aforementioned fluxes were also studied in detail. NH<sub>4</sub>Cl was found to be the best among all the fluxes taken and the photoluminescence intensity of phosphor gets enhanced by 1.43 times of without flux. The Judd-Ofelt theory was employed for determination of spectral parameters from photoluminescent emission spectra. The temperature dependent photoluminescent studies establishes stability of phosphor emission at operating temperatures. The CIE coordinates were evaluated that confirms the pure red emission under n-UV excitation. All the studies indicate the potential of the said phosphor in phosphor converted white light emitting diodes as red emitter and indoor lighting.</p></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142173256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2024-09-12DOI: 10.1016/j.physb.2024.416539
Density functional theory is applied to investigate structural, mechanical, electronic, thermoelectric, thermodynamic and optical properties of the inorganic vacancy ordered double perovskite In2PdCl6 (IPC). It shows stability in rock-salt structure. It is thermodynamically, dynamically and mechanically stable, elastically anisotropic and ductile with dominant metallic bonding and high melting temperature. It is a semiconductor with direct band-gap of 1.25 eV, which makes it a potential photovoltaic material. It is also a potential thermoelectric material in the temperature regime 600–800 K. Response of different thermodynamic parameters of the IPC to temperature and pressure variation has also been studied. The IPC shows high optical absorption in the almost entire UV region to the violet of the visible spectrum, which is supported by the calculated optical gap of 2.77 eV. Therefore, the IPC may be a potential candidate for optoelectronic and photovoltaic applications in the entire UV to the violet of the visible spectrum.
应用密度泛函理论研究了无机空位有序双包晶In2PdCl6(IPC)的结构、机械、电子、热电、热力学和光学特性。它在岩盐结构中表现出稳定性。它具有热力学、动力学和机械稳定性,弹性各向异性和韧性,金属键占主导地位,熔化温度高。它是一种直接带隙为 1.25 eV 的半导体,因此是一种潜在的光伏材料。此外,还研究了 IPC 不同热力学参数对温度和压力变化的响应。IPC 在几乎整个紫外区到可见光谱的紫光区都显示出较高的光吸收,这一点得到了 2.77 eV 光隙计算值的支持。因此,在整个紫外到可见光谱的紫光区,IPC 可能是光电和光伏应用的潜在候选材料。
{"title":"First principle investigation of some physical properties and applications of lead-free vacancy ordered double perovskite In2PdCl6 (IPC)","authors":"","doi":"10.1016/j.physb.2024.416539","DOIUrl":"10.1016/j.physb.2024.416539","url":null,"abstract":"<div><p>Density functional theory is applied to investigate structural, mechanical, electronic, thermoelectric, thermodynamic and optical properties of the inorganic vacancy ordered double perovskite In<sub>2</sub>PdCl<sub>6</sub> (IPC). It shows stability in rock-salt structure. It is thermodynamically, dynamically and mechanically stable, elastically anisotropic and ductile with dominant metallic bonding and high melting temperature. It is a semiconductor with direct band-gap of 1.25 eV, which makes it a potential photovoltaic material. It is also a potential thermoelectric material in the temperature regime 600–800 <em>K</em>. Response of different thermodynamic parameters of the IPC to temperature and pressure variation has also been studied. The IPC shows high optical absorption in the almost entire UV region to the violet of the visible spectrum, which is supported by the calculated optical gap of 2.77 eV. Therefore, the IPC may be a potential candidate for optoelectronic and photovoltaic applications in the entire UV to the violet of the visible spectrum.</p></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142240466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2024-09-12DOI: 10.1016/j.physb.2024.416527
We fabricated Ba0.8Sr0.2TiO (BSTO)/LaCuO (LCO) heterostructure on SrTiO (STO) substrate and investigated its structure and physical properties. X-ray diffraction and reciprocal space mapping confirm the epitaxial growth of BSTO/LCO/STO heterostructure. X-ray photoelectron spectroscopy and UV–Visible spectroscopy measurements reveal a straddling band alignment of the BSTO/LCO heterojunction. Such band alignment facilitates the accumulation of both electrons and holes at the interface. Their movement depends on the direction of the internal field of the BSTO film. Electrical transport measurements have revealed a signature of insulator-to-metal transition (IMT) in response to applied gate voltages . Hall measurements confirm the presence of electron and hole type charge carriers under +V and −V, respectively. We have proposed a screening mechanism linked to the polarization state of the BSTO film to explain the observed IMT.
{"title":"Gate induced metallicity and absence of superconductivity in BSTO/LCO heterostructure","authors":"","doi":"10.1016/j.physb.2024.416527","DOIUrl":"10.1016/j.physb.2024.416527","url":null,"abstract":"<div><p>We fabricated Ba<sub>0.8</sub>Sr<sub>0.2</sub>TiO<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> (BSTO)/La<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>CuO<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span> (LCO) heterostructure on SrTiO<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> (STO) substrate and investigated its structure and physical properties. X-ray diffraction and reciprocal space mapping confirm the epitaxial growth of BSTO/LCO/STO heterostructure. X-ray photoelectron spectroscopy and UV–Visible spectroscopy measurements reveal a straddling band alignment of the BSTO/LCO heterojunction. Such band alignment facilitates the accumulation of both electrons and holes at the interface. Their movement depends on the direction of the internal field of the BSTO film. Electrical transport measurements have revealed a signature of insulator-to-metal transition (IMT) in response to applied gate voltages <span><math><mrow><mo>±</mo><msub><mrow><mi>V</mi></mrow><mrow><mi>g</mi></mrow></msub></mrow></math></span>. Hall measurements confirm the presence of electron and hole type charge carriers under +<em>V</em><span><math><msub><mrow></mrow><mrow><mi>g</mi></mrow></msub></math></span> and −<em>V</em><span><math><msub><mrow></mrow><mrow><mi>g</mi></mrow></msub></math></span>, respectively. We have proposed a screening mechanism linked to the polarization state of the BSTO film to explain the observed IMT.</p></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142239655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2024-09-12DOI: 10.1016/j.physb.2024.416501
There is an increase in demand of the next-generation spintronic devices with stable structural and magnetic properties in varying temperatures. An orthoferrites structure of the Pnma space group has been successfully prepared using high temperature solid-state reaction. In the (SFO) material, ions occupy edge-cantered and face-cantered positions forming the tilted octahedrons with Glazer's notation tilt . The ordering of the rare-earth ions at compensation temperature (, spin-flip transition in the range of , and a second-type spin-reorientation transition around the anisotropy barrier with lower and higher transitional temperatures, and respectively. The canting of spins along with disordered spins at the surface results in a non-zero and unsaturated magnetization. It is inferred that thermal activation of particle's moment over the anisotropy barriers (known as Kneller's law) only occurs above room temperature.
{"title":"Weak ferromagnetic interactions of Sm2Fe2O5+δ induced by coupling of the crystal and related lattice vibrations","authors":"","doi":"10.1016/j.physb.2024.416501","DOIUrl":"10.1016/j.physb.2024.416501","url":null,"abstract":"<div><p>There is an increase in demand of the next-generation spintronic devices with stable structural and magnetic properties in varying temperatures. An orthoferrites structure of the <em>Pnma</em> space group has been successfully prepared using high temperature solid-state reaction. In the <span><math><mrow><msub><mtext>Sm</mtext><mn>2</mn></msub><msub><mtext>Fe</mtext><mn>2</mn></msub><msub><mi>O</mi><mrow><mn>5</mn><mo>+</mo><mi>δ</mi></mrow></msub></mrow></math></span> (SFO) material, <span><math><mrow><mi>F</mi><msup><mi>e</mi><mrow><mn>3</mn><mo>+</mo></mrow></msup></mrow></math></span> ions occupy edge-cantered and face-cantered positions forming the tilted <span><math><mrow><mtext>Fe</mtext><msub><mi>O</mi><mn>6</mn></msub></mrow></math></span> octahedrons with Glazer's notation tilt <span><math><mrow><msup><mi>a</mi><mo>−</mo></msup><msup><mi>a</mi><mo>−</mo></msup><msup><mi>c</mi><mo>+</mo></msup></mrow></math></span>. The ordering of the rare-earth ions at compensation temperature (<span><math><mrow><mrow><msub><mi>T</mi><mtext>comp</mtext></msub><mo>=</mo><mn>2.3</mn><mspace></mspace><mi>K</mi></mrow><mo>)</mo></mrow></math></span>, spin-flip transition in the range of <span><math><mrow><mn>9.4</mn><mo>−</mo><mn>45.6</mn><mspace></mspace><mi>K</mi></mrow></math></span>, and a second-type spin-reorientation transition around the anisotropy barrier with lower and higher transitional temperatures, <span><math><mrow><msub><mi>T</mi><mi>L</mi></msub><mo>=</mo><mn>465</mn></mrow></math></span> and <span><math><mrow><msub><mi>T</mi><mi>H</mi></msub><mo>=</mo><mn>480</mn><mspace></mspace><mi>K</mi></mrow></math></span> respectively. The canting of spins along with disordered spins at the surface results in a non-zero <span><math><mrow><msub><mi>T</mi><mtext>comp</mtext></msub></mrow></math></span> and unsaturated magnetization. It is inferred that thermal activation of particle's moment over the anisotropy barriers (known as Kneller's law) only occurs above room temperature.</p></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0921452624008421/pdfft?md5=7d5882940a3d3cca79a3c83ffce23e51&pid=1-s2.0-S0921452624008421-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142230621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1016/j.physb.2024.416518
We report on the dual effects of ion implantation and swift heavy ion on the optical and structural characteristics of polyethylene terephthalate (PET) films using UV–Vis spectrophotometry, FTIR and X-ray diffraction measurements. Samples were first implanted with 150 keV Ag-ions at different fluences of 1 , 5 , and 1 ions/cm, and thereafter irradiated with 30 MeV Au-ions at different fluences, while analysing elemental depth profile in situ on the Time of Flight Heavy Ions Elastic Recoil Detection (ToF-Hi-ERDA) instrument. The elemental depth profile measurements showed considerable atomic depletion of hydrogen from 36% down to below 6% and oxygen from 18% to about 5%. The proportion of carbon increased from 45% to over 87%. The optical bandgap decreased with increasing ion implantation fluence and reduced even further on irradiation with 30 MeV 197Au-ions. The most notable outcome of the implantation was the onset of the precipitation of gold nanoparticles (Au-NPs) in the PET matrix, marked by Localised Surface Plasmon Resonance effects, coincided with a relatively significant drop in the bandgap energy. This latter effect could only be best explained as the result of these Au-NPs in the PET. This suggests that optical bandgap tuning in polymer films, usually achievable through high fluence implantation at low energy (i.e., keV), could also be realized through low fluence irradiation with MeV energy ions. It is surmised that, for the noble metals, NP-induced bandgap modification in PET precludes the need for high fluence to achieve the same. This has the obvious advantage of bandgap alterations at much lower structural damage to the target polymer. As reported by FTIR results, one can observe structural changes with the formation of new chemical bonds on thin films. X-ray diffraction results exhibited one prominent peak corresponding to the (100) plane, which varies in intensity with increased implantation fluence, suggesting a change in the crystallinity of the PET. The decrease in (100) peak or crystallinity was well connected with the presence and decrease of 847, 970, and 1471 cm−1 peaks, which were assigned to the ethylene glycol molecular groups.
{"title":"Optical and structural transformations in polyethylene terephthalate (PET) films subjected to Ag+-ion implantation and subsequent Au7+-ion irradiation","authors":"","doi":"10.1016/j.physb.2024.416518","DOIUrl":"10.1016/j.physb.2024.416518","url":null,"abstract":"<div><p>We report on the dual effects of ion implantation and swift heavy ion on the optical and structural characteristics of polyethylene terephthalate (PET) films using UV–Vis spectrophotometry, FTIR and X-ray diffraction measurements. Samples were first implanted with 150 keV Ag<span><math><msup><mrow></mrow><mrow><mo>+</mo></mrow></msup></math></span>-ions at different fluences of 1 <span><math><mrow><mo>×</mo><mspace></mspace><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>16</mn></mrow></msup></mrow></math></span>, 5 <span><math><mrow><mo>×</mo><mspace></mspace><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>16</mn></mrow></msup></mrow></math></span>, and 1 <span><math><mrow><mo>×</mo><mspace></mspace><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>17</mn></mrow></msup></mrow></math></span> ions/cm<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span>, and thereafter irradiated with 30 MeV Au<span><math><msup><mrow></mrow><mrow><mn>7</mn><mo>+</mo></mrow></msup></math></span>-ions at different fluences, while analysing elemental depth profile in situ on the Time of Flight Heavy Ions Elastic Recoil Detection (ToF-Hi-ERDA) instrument. The elemental depth profile measurements showed considerable atomic depletion of hydrogen from 36% down to below 6% and oxygen from 18% to about 5%. The proportion of carbon increased from 45% to over 87%. The optical bandgap decreased with increasing ion implantation fluence and reduced even further on irradiation with 30 MeV <sup>197</sup>Au<span><math><msup><mrow></mrow><mrow><mn>7</mn><mo>+</mo></mrow></msup></math></span>-ions. The most notable outcome of the implantation was the onset of the precipitation of gold nanoparticles (Au-NPs) in the PET matrix, marked by Localised Surface Plasmon Resonance effects, coincided with a relatively significant drop in the bandgap energy. This latter effect could only be best explained as the result of these Au-NPs in the PET. This suggests that optical bandgap tuning in polymer films, usually achievable through high fluence implantation at low energy (i.e., keV), could also be realized through low fluence irradiation with MeV energy ions. It is surmised that, for the noble metals, NP-induced bandgap modification in PET precludes the need for high fluence to achieve the same. This has the obvious advantage of bandgap alterations at much lower structural damage to the target polymer. As reported by FTIR results, one can observe structural changes with the formation of new chemical bonds on thin films. X-ray diffraction results exhibited one prominent peak corresponding to the (100) plane, which varies in intensity with increased implantation fluence, suggesting a change in the crystallinity of the PET. The decrease in (100) peak or crystallinity was well connected with the presence and decrease of 847, 970, and 1471 cm<sup>−1</sup> peaks, which were assigned to the ethylene glycol molecular groups.</p></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142167167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2024-09-11DOI: 10.1016/j.physb.2024.416536
This investigation employs first-principles calculations with the Generalized Gradient Approximation (GGA) and modified Becke-Johnson (mBJ) exchange-correlation functionals, employing the Full-Potential Linearized Augmented Plane Wave (FP-LAPW) method. The main objective is to investigate the double perovskites Ba2SmMoO6 and Ba2EuMoO6. We conduct a thorough analysis of the structural, electrical, magnetic, thermoelectric and optical properties of these materials. Both compounds are stable in ferromagnetic phase, according to structural studies. Ba2SmMoO6 has a 3.80 eV energy gap, aligned with the W-X direction, which exhibits half-metallic behavior. On the other hand, Ba2EuMoO6 has a 3.03 eV energy gap that is directly aligned with the X-X direction, using mBJ-GGA. Magnetic investigation revealed a total spin magnetic moment of 7 μB for Ba2EuMoO6, mainly due to Eu (5.98 μB) and 6 μB for Ba2SmMoO6, mainly due to Sm (4.53 μB). It was found that both materials have high Seebeck coefficients and electrical conductivities at high temperatures, with performance improving with temperature. However, the figure of merit (ZT) approaches a value of one, indicating their potential for use in thermoelectric applications at high temperatures. Ba2SmMoO6 and Ba2EuMoO6 are identified as highly favourable options for effective thermoelectric devices. The high UV absorption, the unique refractive and reflective properties offer potential in photonics, optical coatings, and other fields requiring precise light manipulation.
{"title":"First-principles investigation of spin characteristics and thermoelectric properties in Ba2SmMoO6 and Ba2EuMoO6 double perovskites","authors":"","doi":"10.1016/j.physb.2024.416536","DOIUrl":"10.1016/j.physb.2024.416536","url":null,"abstract":"<div><p>This investigation employs first-principles calculations with the Generalized Gradient Approximation (GGA) and modified Becke-Johnson (mBJ) exchange-correlation functionals, employing the Full-Potential Linearized Augmented Plane Wave (FP-LAPW) method. The main objective is to investigate the double perovskites Ba<sub>2</sub>SmMoO<sub>6</sub> and Ba<sub>2</sub>EuMoO<sub>6</sub>. We conduct a thorough analysis of the structural, electrical, magnetic, thermoelectric and optical properties of these materials. Both compounds are stable in ferromagnetic phase, according to structural studies. Ba<sub>2</sub>SmMoO<sub>6</sub> has a 3.80 eV energy gap, aligned with the W-X direction, which exhibits half-metallic behavior. On the other hand, Ba<sub>2</sub>EuMoO<sub>6</sub> has a 3.03 eV energy gap that is directly aligned with the X-X direction, using mBJ-GGA. Magnetic investigation revealed a total spin magnetic moment of 7 μB for Ba<sub>2</sub>EuMoO<sub>6</sub>, mainly due to Eu (5.98 μB) and 6 μB for Ba<sub>2</sub>SmMoO<sub>6</sub>, mainly due to Sm (4.53 μB). It was found that both materials have high Seebeck coefficients and electrical conductivities at high temperatures, with performance improving with temperature. However, the figure of merit (ZT) approaches a value of one, indicating their potential for use in thermoelectric applications at high temperatures. Ba<sub>2</sub>SmMoO<sub>6</sub> and Ba<sub>2</sub>EuMoO<sub>6</sub> are identified as highly favourable options for effective thermoelectric devices. The high UV absorption, the unique refractive and reflective properties offer potential in photonics, optical coatings, and other fields requiring precise light manipulation.</p></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142240503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}