Pub Date : 2024-11-22DOI: 10.1016/j.cap.2024.11.012
Sanjith Unithrattil , Taewon Min , Gopinathan Anoop , Jun Young Lee , Tae Yeon kim , Shibnath Samanta , Yubo Qi , Jiahao Zhang , Seung Hyun Hwang , Hyeon Jun Lee , Kun Guo , Su Yong Lee , Yasuhiko Imai , Osami Sakata , Keisuke Shimizu , Kei Shigematsu , Hajime Hojo , Kui Yao , Masaki Azuma , Jaekwang Lee , Ji Young Jo
Understanding the ultra-fast dynamics of ferroelectric materials is essential for advancing the development of next-generation high speed electronic and photonic devices. Here, the ultrafast piezoelectric response of cobalt-substituted BiFeO3 (BiFe1-xCoxO3) with x = 0.15, consisting of morphotropic phase boundary of monoclinic MC and MA –type phases is investigated. The real-time piezoelectric response in (001)-oriented BiFe0.85Co0.15O3 (BFCO) epitaxial thin film was monitored using the time-resolved X-ray microdiffraction technique under an applied electric field with pulse widths 70 ns and 100 ns. The BFCO thin film yielded a high piezoelectric strain of approximately 0.53 % along [001] direction, with a giant c/a ratio (∼1.26) at an electric field of 1.3 MV/cm and a pulse width of 100 ns, with a piezoelectric coefficient () of 40 pm/V. This finding is an important step towards the development of a high performance lead-free piezoelectric material for ultrafast operations in advanced technological applications.
{"title":"Nanosecond electric pulse-induced ultrafast piezoelectric responses in Co3+ substituted BiFeO3 epitaxial thin films","authors":"Sanjith Unithrattil , Taewon Min , Gopinathan Anoop , Jun Young Lee , Tae Yeon kim , Shibnath Samanta , Yubo Qi , Jiahao Zhang , Seung Hyun Hwang , Hyeon Jun Lee , Kun Guo , Su Yong Lee , Yasuhiko Imai , Osami Sakata , Keisuke Shimizu , Kei Shigematsu , Hajime Hojo , Kui Yao , Masaki Azuma , Jaekwang Lee , Ji Young Jo","doi":"10.1016/j.cap.2024.11.012","DOIUrl":"10.1016/j.cap.2024.11.012","url":null,"abstract":"<div><div>Understanding the ultra-fast dynamics of ferroelectric materials is essential for advancing the development of next-generation high speed electronic and photonic devices. Here, the ultrafast piezoelectric response of cobalt-substituted BiFeO<sub>3</sub> (BiFe<sub>1-<em>x</em></sub>Co<sub><em>x</em></sub>O<sub>3</sub>) with <em>x</em> = 0.15, consisting of morphotropic phase boundary of monoclinic M<sub>C</sub> and M<sub>A</sub> –type phases is investigated. The real-time piezoelectric response in (001)-oriented BiFe<sub>0.85</sub>Co<sub>0.15</sub>O<sub>3</sub> (BFCO) epitaxial thin film was monitored using the time-resolved X-ray microdiffraction technique under an applied electric field with pulse widths 70 ns and 100 ns. The BFCO thin film yielded a high piezoelectric strain of approximately 0.53 % along [001] direction, with a giant <em>c</em>/<em>a</em> ratio (∼1.26) at an electric field of 1.3 MV/cm and a pulse width of 100 ns, with a piezoelectric coefficient (<span><math><mrow><msub><mi>d</mi><mn>33</mn></msub></mrow></math></span>) of 40 pm/V. This finding is an important step towards the development of a high performance lead-free piezoelectric material for ultrafast operations in advanced technological applications.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"70 ","pages":"Pages 76-80"},"PeriodicalIF":2.4,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142720528","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}
Pub Date : 2024-11-20DOI: 10.1016/j.cap.2024.11.011
Asif Ullah, Thanh-Huong Thi Nguyen, Sanghoon Kim
The field of spin caloritronics, which explores the interplay between spin current and thermal effects, is a promising path for new energy-efficient-electronic devices. However, current thermoelectric technologies are limited by conventional material choices and device designs. Antiferromagnetic materials, with their unique spin structure and magnetic characteristics, provide new opportunities for enhanced thermoelectric performance through spin-dependent effects. This review covers origin and measurement methodologies of anomalous Nernst effect, focusing on non-collinear antiferromagnets. By presenting insights into the relationship between electronic structure and thermoelectric performance as well as their practical measurements, this review aims to pave the way for developing AFM-based thermoelectric devices in advanced energy technologies.
{"title":"Observation of anomalous Nernst effect in non-collinear antiferromagnets","authors":"Asif Ullah, Thanh-Huong Thi Nguyen, Sanghoon Kim","doi":"10.1016/j.cap.2024.11.011","DOIUrl":"10.1016/j.cap.2024.11.011","url":null,"abstract":"<div><div>The field of spin caloritronics, which explores the interplay between spin current and thermal effects, is a promising path for new energy-efficient-electronic devices. However, current thermoelectric technologies are limited by conventional material choices and device designs. Antiferromagnetic materials, with their unique spin structure and magnetic characteristics, provide new opportunities for enhanced thermoelectric performance through spin-dependent effects. This review covers origin and measurement methodologies of anomalous Nernst effect, focusing on non-collinear antiferromagnets. By presenting insights into the relationship between electronic structure and thermoelectric performance as well as their practical measurements, this review aims to pave the way for developing AFM-based thermoelectric devices in advanced energy technologies.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"70 ","pages":"Pages 51-60"},"PeriodicalIF":2.4,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698501","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}
Pub Date : 2024-11-19DOI: 10.1016/j.cap.2024.11.010
Yu Chen, Guihong Song, Zhihao Ben, Yusheng Wu, Junhua You
The β-Cu2+xSe/CuInSe2 multilayer films with different modulation period were prepared and studied. The results showed that the deposited films possessed obvious layered structure. The room temperature carrier concentration, mobility, electrical conductivity and thermal conductivity decreased, but the Seebeck coefficient and power factor and relative thermoelectric figure of merit increased with reducing modulation period of deposited β-Cu2-xSe/CuInSe2 multilayer films. The linear reduction of carrier concentration and mobility and the decrease in thermal conductivity with modulation period was attributed to the scattering of carriers and phonons by layer interface and grain boundary, respectively. The sample with the smallest modulation period (160 nm) possessed the highest power factor of ∼0.74 at room temperature and ∼1.56 mW m−1 K−2 at 405 °C. The insertion of heterogeneous layer into films is an effective method to increase Seebeck coefficient and decrease thermal conductivity, thus increasing thermoelectric figure of merit of films.
{"title":"Improved thermoelectric properties of the β-Cu2+xSe/CuInSe2 multilayer films by layer interface scattering","authors":"Yu Chen, Guihong Song, Zhihao Ben, Yusheng Wu, Junhua You","doi":"10.1016/j.cap.2024.11.010","DOIUrl":"10.1016/j.cap.2024.11.010","url":null,"abstract":"<div><div>The β-Cu<sub>2+x</sub>Se/CuInSe<sub>2</sub> multilayer films with different modulation period were prepared and studied. The results showed that the deposited films possessed obvious layered structure. The room temperature carrier concentration, mobility, electrical conductivity and thermal conductivity decreased, but the Seebeck coefficient and power factor and relative thermoelectric figure of merit increased with reducing modulation period of deposited β-Cu<sub>2-x</sub>Se/CuInSe<sub>2</sub> multilayer films. The linear reduction of carrier concentration and mobility and the decrease in thermal conductivity with modulation period was attributed to the scattering of carriers and phonons by layer interface and grain boundary, respectively. The sample with the smallest modulation period (160 nm) possessed the highest power factor of ∼0.74 at room temperature and ∼1.56 mW m<sup>−1</sup> K<sup>−2</sup> at 405 °C. The insertion of heterogeneous layer into films is an effective method to increase Seebeck coefficient and decrease thermal conductivity, thus increasing thermoelectric figure of merit of films.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"70 ","pages":"Pages 1-10"},"PeriodicalIF":2.4,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698494","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}
Pub Date : 2024-11-19DOI: 10.1016/j.cap.2024.11.004
Ye-Ryoung Lee
Optical techniques are essential in biomedical research, enabling high-resolution, non-invasive imaging of biological tissues. However, imaging depth in optical microscopy is limited by multiple scattering in scattering media, such as biological tissues. Various methods have been developed to overcome this limitation, and numerical simulations have played an important role in developing new imaging techniques. Traditional simulations often use simple random matrices to represent multiple-scattered waves, which overly simplifies their behavior and may impact the accuracy of image quality assessments. In this study, we introduce various types of simulated multiple scattering matrices to better capture the characteristics of scattered waves. We systematically analyze the correlation properties of these matrices and evaluate their impact on high-resolution imaging quality. This work provides a foundation for selecting appropriate matrix types for simulating multiple scattering effects, aiding in the effective testing and validation of new microscopy techniques in scattering media.
{"title":"Impact analysis of various types of simulated multiple scattering matrices on the numerical simulation of high-resolution imaging in scattering media","authors":"Ye-Ryoung Lee","doi":"10.1016/j.cap.2024.11.004","DOIUrl":"10.1016/j.cap.2024.11.004","url":null,"abstract":"<div><div>Optical techniques are essential in biomedical research, enabling high-resolution, non-invasive imaging of biological tissues. However, imaging depth in optical microscopy is limited by multiple scattering in scattering media, such as biological tissues. Various methods have been developed to overcome this limitation, and numerical simulations have played an important role in developing new imaging techniques. Traditional simulations often use simple random matrices to represent multiple-scattered waves, which overly simplifies their behavior and may impact the accuracy of image quality assessments. In this study, we introduce various types of simulated multiple scattering matrices to better capture the characteristics of scattered waves. We systematically analyze the correlation properties of these matrices and evaluate their impact on high-resolution imaging quality. This work provides a foundation for selecting appropriate matrix types for simulating multiple scattering effects, aiding in the effective testing and validation of new microscopy techniques in scattering media.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"70 ","pages":"Pages 21-26"},"PeriodicalIF":2.4,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697805","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}
Pub Date : 2024-11-16DOI: 10.1016/j.cap.2024.11.002
Jiho Kim , Boknam Chae , Sangsul Lee
This article introduces several cases of s-SNOM (Scattering-type scanning near-field optical microscopy) based on a SPM (Scanning probe microscopy) for chemical thin film. A highly concentrated near-field infrared performs the chemical analysis of s-SNOM at the sharp apex of the metal-coated atomic microscope tip. This attractive technique, which provides both surface morphology and chemical information of the material simultaneously, various studies have been published, including surface polariton propagation, Moire superlattice, and ballistic valley transport. Further, s-SNOM successfully visualized the formation of lamellar nanostructures of BCP and the latent image of photoresist formed by EUV (extreme ultraviolet). These results were cross-validated through traditional GIWAXS (Grazing-incidence wide-angle X-ray scattering) and FTIR (Fourier transform infrared) analysis. s-SNOM is a useful tool for providing new insights into material analysis by visualizing nanoscale chemical information of local regions that conventional measurements could not confirm.
{"title":"Near-field infrared spectroscopy: Advanced research method in thin film analysis","authors":"Jiho Kim , Boknam Chae , Sangsul Lee","doi":"10.1016/j.cap.2024.11.002","DOIUrl":"10.1016/j.cap.2024.11.002","url":null,"abstract":"<div><div>This article introduces several cases of s-SNOM (Scattering-type scanning near-field optical microscopy) based on a SPM (Scanning probe microscopy) for chemical thin film. A highly concentrated near-field infrared performs the chemical analysis of s-SNOM at the sharp apex of the metal-coated atomic microscope tip. This attractive technique, which provides both surface morphology and chemical information of the material simultaneously, various studies have been published, including surface polariton propagation, Moire superlattice, and ballistic valley transport. Further, s-SNOM successfully visualized the formation of lamellar nanostructures of BCP and the latent image of photoresist formed by EUV (extreme ultraviolet). These results were cross-validated through traditional GIWAXS (Grazing-incidence wide-angle X-ray scattering) and FTIR (Fourier transform infrared) analysis. s-SNOM is a useful tool for providing new insights into material analysis by visualizing nanoscale chemical information of local regions that conventional measurements could not confirm.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"70 ","pages":"Pages 41-50"},"PeriodicalIF":2.4,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2024-11-15DOI: 10.1016/j.cap.2024.11.003
Hwiwon Seo , Haneul Lee , Ji-Won Kwon , Gwanjoong Kim , Ingyu Lee , Gon-Ho Kim
This study investigates the electron thermal properties in Argon and Ar/O2 inductively coupled plasmas using global model based on Langmuir probe data. The sensor-data driven global model (GM) is improved to simulate the power coupling efficiency and an electron energy distribution simultaneously. It reveals that the heating characteristic changes the thermal state and radical generation with input power, pressure and gas mixture ratio. The analysis results of probe data from the global model provide information on the plasma thermal characteristics under efficient operating conditions of process plasma. It provides the advantage of offering insights into the causes of variations in the plasma thermal equilibrium state with operating conditions in ICP, which are limited to obtain from the sensor or the general GM. This makes it highly promising as a simulation method for developing process recipes.
{"title":"Analysis of electron thermal properties in Ar/O2 inductively coupled plasmas: A global model simulation using Langmuir probe data","authors":"Hwiwon Seo , Haneul Lee , Ji-Won Kwon , Gwanjoong Kim , Ingyu Lee , Gon-Ho Kim","doi":"10.1016/j.cap.2024.11.003","DOIUrl":"10.1016/j.cap.2024.11.003","url":null,"abstract":"<div><div>This study investigates the electron thermal properties in Argon and Ar/O2 inductively coupled plasmas using global model based on Langmuir probe data. The sensor-data driven global model (GM) is improved to simulate the power coupling efficiency and an electron energy distribution simultaneously. It reveals that the heating characteristic changes the thermal state and radical generation with input power, pressure and gas mixture ratio. The analysis results of probe data from the global model provide information on the plasma thermal characteristics under efficient operating conditions of process plasma. It provides the advantage of offering insights into the causes of variations in the plasma thermal equilibrium state with operating conditions in ICP, which are limited to obtain from the sensor or the general GM. This makes it highly promising as a simulation method for developing process recipes.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"70 ","pages":"Pages 27-40"},"PeriodicalIF":2.4,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697806","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}
Pub Date : 2024-11-15DOI: 10.1016/j.cap.2024.11.009
Charu Dwivedi , Stuti Srivastava , Preetam Singh
We have studied the effect of film thickness (120, 180, and 286 nm) on the dual gas (NO & NO2) sensing performance of DC magnetron sputtered WO3 thin films deposited at room temperature. WO3 shows strong absorption from visible light to the infrared region. An unusual peak originates at 467.6 nm (film thickness 286 nm) instead of a broadband tail, usually found in WO3, which has been linked with oxygen vacancies. A high response of ∼196 at 150 °C for 50 ppm NO and ∼50 at 250 °C for 50 ppm NO2 is achieved for 286 nm film, which can be associated with Localized Surface Plasmon Resonance while a low response/recovery time of ∼39s/99s is obtained for 120 nm film at 200 °C for NO gas, which is its best operating temperature too (sensor response ∼100). Even under a high humidity (90 %) environment, the sensor detected 50 ppm of NO.
{"title":"Highly selective dual gas (NO & NO2) sensing depended on the operating temperature of WO3 thin films sputtered at room temperature","authors":"Charu Dwivedi , Stuti Srivastava , Preetam Singh","doi":"10.1016/j.cap.2024.11.009","DOIUrl":"10.1016/j.cap.2024.11.009","url":null,"abstract":"<div><div>We have studied the effect of film thickness (120, 180, and 286 nm) on the dual gas (NO & NO<sub>2</sub>) sensing performance of DC magnetron sputtered WO<sub>3</sub> thin films deposited at room temperature. WO<sub>3</sub> shows strong absorption from visible light to the infrared region. An unusual peak originates at 467.6 nm (film thickness 286 nm) instead of a broadband tail, usually found in WO<sub>3</sub>, which has been linked with oxygen vacancies. A high response of ∼196 at 150 °C for 50 ppm NO and ∼50 at 250 °C for 50 ppm NO<sub>2</sub> is achieved for 286 nm film, which can be associated with Localized Surface Plasmon Resonance while a low response/recovery time of ∼39s/99s is obtained for 120 nm film at 200 °C for NO gas, which is its best operating temperature too (sensor response ∼100). Even under a high humidity (90 %) environment, the sensor detected 50 ppm of NO.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"69 ","pages":"Pages 70-80"},"PeriodicalIF":2.4,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698212","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}
Pub Date : 2024-11-15DOI: 10.1016/j.cap.2024.11.007
Habeeb Olaitan Suleiman , Eun Young Jung , Hyojun Jang , Jae Young Kim , Heung-Sik Tae
Despite advancements in research on conducting polymers, obtaining stable conductivity in thin films remains challenging. Although ex-situ iodine (I2) doping methods have exhibited promise, they often result in unstable conductivity with increasing exposure time. This study aimed to produce polythiophene (PTh) nanostructure films with stable electrical conductivity through optimized ex-situ I2-doping techniques using a newly fabricated atmospheric pressure plasma reactor for PTh deposition. I2 charge carriers in the form of solid and liquid were separately incorporated into the PTh at room temperatures and 60 °C. FE-SEM, EDS, and FT-IR revealed an enhanced molecular structure, the distribution of element and functional chemical composition of the doped PTh nanostructure films, respectively. Compared to solid I2 doping, the liquid-doped PTh exhibited improved electrical conductivity and stable conductivity over a long period. The results also proved promising for reliable applications in electronic devices, making ex-situ liquid I2 doping a good technique.
{"title":"Comparison of ex-situ solid and liquid iodine doping methods at different temperatures to improve electrical properties of polythiophene nanostructure films synthesized by atmospheric pressure plasma process","authors":"Habeeb Olaitan Suleiman , Eun Young Jung , Hyojun Jang , Jae Young Kim , Heung-Sik Tae","doi":"10.1016/j.cap.2024.11.007","DOIUrl":"10.1016/j.cap.2024.11.007","url":null,"abstract":"<div><div>Despite advancements in research on conducting polymers, obtaining stable conductivity in thin films remains challenging. Although ex-situ iodine (I<sub>2</sub>) doping methods have exhibited promise, they often result in unstable conductivity with increasing exposure time. This study aimed to produce polythiophene (PTh) nanostructure films with stable electrical conductivity through optimized ex-situ I<sub>2</sub>-doping techniques using a newly fabricated atmospheric pressure plasma reactor for PTh deposition. I<sub>2</sub> charge carriers in the form of solid and liquid were separately incorporated into the PTh at room temperatures and 60 °C. FE-SEM, EDS, and FT-IR revealed an enhanced molecular structure, the distribution of element and functional chemical composition of the doped PTh nanostructure films, respectively. Compared to solid I<sub>2</sub> doping, the liquid-doped PTh exhibited improved electrical conductivity and stable conductivity over a long period. The results also proved promising for reliable applications in electronic devices, making ex-situ liquid I<sub>2</sub> doping a good technique.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"70 ","pages":"Pages 11-20"},"PeriodicalIF":2.4,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697804","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}
Pub Date : 2024-11-15DOI: 10.1016/j.cap.2024.11.008
Saiki Kitagawa , Toshihiro Nakamura
Epitaxial manganese-doped indium tin oxide (Mn-doped ITO) films with different Mn concentrations were deposited on single-crystal yttria-stabilized zirconia substrates using radio-frequency magnetron sputtering. The carrier concentration of the epitaxial Mn-doped ITO films could be controlled by changing the Mn doping concentration. The optical bandgaps of the films increased with the increase in the carrier concentration. Room-temperature ferromagnetism was observed in all films irrespective of the Mn concentration. The saturation magnetizations of the films increased with the increase in the carrier concentration, which suggests that delocalized charge carrier-mediated interaction model is one of the most probable mechanisms of the ferromagnetism in the Mn-doped ITO films. We found that the carrier concentration plays a crucial role in controlling optical and magnetic properties of the Mn-doped ITO films. The results of this study provide useful insight into the application of Mn-doped ITO films to ferromagnetic electrodes in spintronic devices.
利用射频磁控溅射技术在单晶钇稳定氧化锆基底上沉积了不同锰浓度的掺锰氧化铟锡（掺锰氧化铟锡）外延薄膜。外延掺锰 ITO 薄膜的载流子浓度可通过改变掺锰浓度来控制。薄膜的光带隙随着载流子浓度的增加而增大。无论锰的浓度如何，所有薄膜都具有室温铁磁性。薄膜的饱和磁化率随着载流子浓度的增加而增加，这表明电荷载流子介导的非局域相互作用模型是掺锰 ITO 薄膜铁磁性的最可能机制之一。我们发现，载流子浓度在控制掺锰 ITO 薄膜的光学和磁学特性方面起着至关重要的作用。这项研究的结果为将掺锰 ITO 薄膜应用于自旋电子器件中的铁磁电极提供了有益的启示。
{"title":"Carrier concentration dependence of optical and magnetic properties in epitaxial manganese-doped indium tin oxide films with different manganese concentrations","authors":"Saiki Kitagawa , Toshihiro Nakamura","doi":"10.1016/j.cap.2024.11.008","DOIUrl":"10.1016/j.cap.2024.11.008","url":null,"abstract":"<div><div>Epitaxial manganese-doped indium tin oxide (Mn-doped ITO) films with different Mn concentrations were deposited on single-crystal yttria-stabilized zirconia substrates using radio-frequency magnetron sputtering. The carrier concentration of the epitaxial Mn-doped ITO films could be controlled by changing the Mn doping concentration. The optical bandgaps of the films increased with the increase in the carrier concentration. Room-temperature ferromagnetism was observed in all films irrespective of the Mn concentration. The saturation magnetizations of the films increased with the increase in the carrier concentration, which suggests that delocalized charge carrier-mediated interaction model is one of the most probable mechanisms of the ferromagnetism in the Mn-doped ITO films. We found that the carrier concentration plays a crucial role in controlling optical and magnetic properties of the Mn-doped ITO films. The results of this study provide useful insight into the application of Mn-doped ITO films to ferromagnetic electrodes in spintronic devices.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"69 ","pages":"Pages 60-69"},"PeriodicalIF":2.4,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698211","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}
Pub Date : 2024-11-13DOI: 10.1016/j.cap.2024.11.005
Dongjin Jang , Minsik Kong , Jong Mok Ok
Many quantum materials undergo phase transitions above room temperature. However, thermodynamic evidence of these phase transitions is relatively scarce. For instance, detailed specific heat anomalies have rarely been reported for the transitions. In addition to considering intrinsic factors that obscure the thermodynamic manifestation of relevant degrees of freedom, it is also important to revisit measurement techniques based on firmly established physical principles. In this study, we introduce a transient heat-flux method for measuring heat capacity of solids, and report a specific heat anomaly in VO2, along with the reproduction of the standard specific heat capacity data of Cu. At present, our method is capable of measuring heat capacities ranging from 1 J/mol⋅K to 400 J/mol⋅K with an uncertainty of 5% across a temperature range from room temperature to 100 °C.
{"title":"Transient heat-flux method for measuring heat capacity: Examples from Cu and VO2","authors":"Dongjin Jang , Minsik Kong , Jong Mok Ok","doi":"10.1016/j.cap.2024.11.005","DOIUrl":"10.1016/j.cap.2024.11.005","url":null,"abstract":"<div><div>Many quantum materials undergo phase transitions above room temperature. However, thermodynamic evidence of these phase transitions is relatively scarce. For instance, detailed specific heat anomalies have rarely been reported for the transitions. In addition to considering intrinsic factors that obscure the thermodynamic manifestation of relevant degrees of freedom, it is also important to revisit measurement techniques based on firmly established physical principles. In this study, we introduce a transient heat-flux method for measuring heat capacity of solids, and report a specific heat anomaly in VO<sub>2</sub>, along with the reproduction of the standard specific heat capacity data of Cu. At present, our method is capable of measuring heat capacities ranging from 1 J/mol⋅K to 400 J/mol⋅K with an uncertainty of 5% across a temperature range from room temperature to 100 °C.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"69 ","pages":"Pages 55-59"},"PeriodicalIF":2.4,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
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