Article
Chemistry, Physical
Nur Amaliyana Raship, Siti Nooraya Mohd Tawil, Nafarizal Nayan, Khadijah Ismail, Anis Suhaili Bakri, Zulkifli Azman, Faezahana Mohkhter
Summary: The influence of doping and co-doping process on ZnO films was characterized, showing successful incorporation of Gd and Al ions into ZnO lattice. The films exhibited high transparency and red-shifted optical band gap with increasing Gd doping concentration. Co-doping with Al resulted in the presence of ferromagnetism and spin polarization. The electrical properties were improved by the incorporation of Al into Gd-doped ZnO thin films.
Article
Optics
Sushama Sushama, Punam Murkute, Hemant Ghadi, Sushil Kumar Pandey, Subhananda Chakrabarti
Summary: Researchers explored the effect of boron and phosphorus co-doping in ZnO thin films, finding that co-doping enhanced phosphorus incorporation and led to improved stability in acceptor behavior for over a year, especially after high-temperature annealing.
JOURNAL OF LUMINESCENCE
(2021)
Article
Chemistry, Physical
R. Kabilan, M. Ashokkumar
Summary: Cu and Cr co-doped ZnO nanopowder was synthesized and annealed at different temperatures. Sample S2 exhibited the best crystallization with the least defects, while samples S1 and S3 showed impurities and lattice distortion. The nanopowders displayed wide absorption and emission bands in UV/violet, blue, and green regions, with room-temperature ferromagnetism observed in all samples.
JOURNAL OF MOLECULAR STRUCTURE
(2022)
Article
Physics, Condensed Matter
Xiang Yu, Yang Gao, Shicheng Sun, Qi Sui, Xiaolei Song, Qiuyu Fan
Summary: The Co content plays a crucial role in the magnetic and electric properties of ZnO:Co films. Increasing the Co content leads to higher surface roughness, crystalline size, electrical conductivity, carrier concentration, mobility, and saturation magnetization in the prepared films.
PHYSICA B-CONDENSED MATTER
(2023)
Article
Materials Science, Multidisciplinary
Chien-Yie Tsay, Shih-Hsun Yu
Summary: The incorporation of Al and Al-B into ZnO thin films can significantly improve the microstructural, surface morphological, electrical and optical properties, particularly enhancing optical transparency and optimizing electrical performance.
Article
Chemistry, Multidisciplinary
Muhammad Amjad, Muhammad Iftikhar Khan, Norah Alwadai, Muhammad Irfan, Ikram-ul-Haq, Hind Albalawi, Aljawhara H. Almuqrin, Maha M. Almoneef, Munawar Iqbal
Summary: In this study, ZnO films co-doped with Mn and La were synthesized using the sol-gel technique, and their structural, optical, and photovoltaic properties were analyzed. The results showed that the co-doped ZnO films exhibited improved photoelectric performance and hold great potential as electrodes for perovskite solar cells.
Article
Chemistry, Physical
Chang Gao, Yu Zhao, Weili Li, Lu Jing, Yulong Qiao, Zhao Wang, Jie Sheng, Lidong Wang, Weidong Fei
Summary: This study reports the high performance anomalous photovoltaic effect observed under white light in Zn1-2x(FexLix)O films fabricated by a low-cost sol-gel process. The photovoltaic effects are found to be closely related to the ferroelectricity of the films, and a photo-to-electron conversion model is proposed to explain the mechanism.
Article
Materials Science, Ceramics
BeiBei Zhu, Cong Chen, ZhiChao Yao, JiaYi Chen, Chuang Jia, ZheHan Wang, RuoMing Tian, Li Tao, Feng Xue, HueyHoon Hng
Summary: The addition of multiple dopants to ZnO significantly reduces its thermal conductivity and improves its thermoelectric performance, leading to a zT value 2.4 times higher than undoped ZnO. This study demonstrates that multiple doped ZnO exhibits better thermoelectric properties than singly doped counterparts, providing an effective approach to enhance the thermoelectric performance of ZnO and other oxides.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2021)
Article
Materials Science, Multidisciplinary
Arpita Das, Alakananda Das, Chirantan Singha, Anirban Bhattacharyya
Summary: The effects of annealing temperature on Al and Mg co-doped ZnO thin films were investigated. It was found that a three-order magnitude reduction in electrical resistivity was achieved for an increase of 100 degrees C annealing temperature, and a 5x increase in magnitude of the photocurrent was observed. The mechanism behind these effects was attributed to the temperature-induced variation in Mg to Al ratio in the films.
Article
Chemistry, Multidisciplinary
R. C. Ramola, Sandhya Negi, Mukesh Rawat, R. C. Singh, Fouran Singh
Summary: Zinc oxide (ZnO) is a versatile material with high thermal conductivity, electron mobility, wide band gap, and exciton binding energy, making it suitable for various device applications. Among these applications, gallium-doped ZnO thin films annealed at 700 degrees Celsius show the highest sensitivity and shortest response and recovery time for ethanol and acetone gases, demonstrating the potential for gas sensing applications.
Article
Metallurgy & Metallurgical Engineering
Emine Guneri, Johnson Henry, Fatma Gode, Nilgun Kalaycioglu Ozpozan
Summary: Pure ZnO and Mn-doped ZnO thin films were prepared by chemical bath deposition method with various Mn doping concentrations. The structural, morphological, and optical properties of the films were analyzed using different techniques. XRD analysis revealed hexagonal structured ZnO in all films, with a peak shift observed in Mn-doped films. The crystallite size increased with Mn doping. The surface morphology of Mn-doped films exhibited irregularly shaped agglomerated particles. The transmittance spectra showed higher transmittance in the visible region, which decreased with Mn doping, indicating increased optical absorption. The band gap of Mn-doped films decreased with Mn doping. Mn-doped films exhibited higher optical and electrical conductivity in the UV region.
JOURNAL OF CENTRAL SOUTH UNIVERSITY
(2023)
Article
Chemistry, Physical
Chia-Hsun Hsu, Xin-Peng Geng, Pao-Hsun Huang, Wan-Yu Wu, Ming-Jie Zhao, Xiao-Ying Zhang, Qi-Hui Huang, Zhan-Bo Su, Zi-Rong Chen, Shui-Yang Lien, Wen-Zhang Zhu
Summary: Aluminum-doped ZnO films were prepared using spatial ALD technique, and the Al doping level was successfully predicted by controlling the ratio of TMA to DEZ vapor molecules. Films prepared under specific conditions showed good electrical properties with a high Al-doping efficiency of 73%.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Applied
Dewangga Oky Bagus Apriandanu, Shinpei Nomura, Satoshi Nakayama, Chihiro Tateishi, Fumiaki Amano
Summary: In this study, Ti4+-doped Fe2O3 was prepared by hydrothermal treatment followed by two-step annealing process. The photoelectrochemical performance of the Ti-doped Fe2O3 photoanodes was significantly enhanced by the two-step annealing, achieving a photocurrent density of 0.55 mA/cm^2 under simulated one-sun illumination.
Article
Materials Science, Multidisciplinary
Yulia E. Samoshkina, Irina S. Edelman, Hsiung Chou, Hsien-Chi Lin, Gopeshwar D. Dwivedi, Dmitry A. Petrov, Sergey M. Zharkov, Galina M. Zeer, Maxim S. Molokeev
Summary: (Co + Al)-doped ZnO films synthesized by RF magnetron sputtering in a mixed atmosphere of Ar + H-2 exhibit superior magnetic and optical properties, showing ferromagnetic behavior at room temperature and high electric conductivity. These characteristics are believed to be associated with defect-related mechanisms.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2021)
Article
Materials Science, Ceramics
Hoa T. Dao, Hisao Makino
Summary: The effects of substrate temperature on the thermal stability of Al-doped ZnO (AZO) films were studied. It was found that a thin AlOx capping layer can prevent thermal degradation and the reduction in carrier concentration. The correlation between Zn desorption and reduction in carrier concentration was observed, with the AlOx layer successfully preventing thermal desorption of Zn.
CERAMICS INTERNATIONAL
(2021)
Article
Chemistry, Multidisciplinary
Piyush Agarwal, Rohit Medwal, Abhishek Kumar, Hironori Asada, Yasuhiro Fukuma, Rajdeep Singh Rawat, Marco Battiato, Ranjan Singh
Summary: The phase reversal of terahertz spin current induced by a femtosecond light pulse demonstrates a new paradigm for ultra-low-power hybrid electronics and photonics, enabled by the interplay of charge, spin, thermal, and optical signals.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Physics, Applied
Utkarsh Shashank, Rohit Medwal, Yoji Nakamura, John Rex Mohan, Razia Nongjai, Asokan Kandasami, Rajdeep Singh Rawat, Hironori Asada, Surbhi Gupta, Yasuhiro Fukuma
Summary: In this study, the damping-like torque efficiency was increased more than 3.5 times by using a better approach of low energy O+ ion implantation in modified Pt-oxide. The spin transmission was improved with a smaller trade-off in the longitudinal resistivity, and the enhanced spin Hall effect in O-implanted Pt was attributed to a side-jumping mechanism. The torques from the O-implanted Pt remained twofold and symmetrical, allowing for quantification using spin-torque ferromagnetic resonance-based line shape analysis.
APPLIED PHYSICS LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Masaaki Imamura, Hironori Asada, Ryo Nishimura, Daisuke Tashima, Jiro Kitagawa
Summary: In this study, we optimized each component of a spin thermoelectric generator and observed its effect on the voltage. By substituting bismuth and aluminum for yttrium and iron in the iron garnet film, a significant increase in voltage was observed.
IEEE TRANSACTIONS ON MAGNETICS
(2022)
Article
Chemistry, Physical
Garima Vashisht, Utkarsh Shashank, Surbhi Gupta, Rohit Medwal, C. L. Dong, C. L. Chen, K. Asokan, Y. Fukuma, S. Annapoorni
Summary: FeCo was found to inhibit the crystalline growth of FePt and exhibit soft ferromagnetic in-plane behavior with defect-driven hard ferromagnetic properties in the out-plane configuration. Only FePt showed an out-plane magnetization component in FeCo/FePt/Si, and the local coordination of Co remained similar regardless of stack order, while the local geometry of Fe varied due to different crystallinity of FePt in the two series.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
M. Imamura, H. Asada, R. Nishimura, Y. Kano, D. Tashima, J. Kitagawa
Summary: Liquid phase epitaxial Bi-substituted YIG films exhibit a large growth-induced magnetic anisotropy perpendicular to the film surface. The anisotropy depends on the melt composition and supercooling in the growth process. Even at a Bi content of 0, the film shows a significant anisotropy. The spin-orbital coupling enhances the thermal energy transfer and increases spin currents for spin-thermoelectric generation.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Avinash Chaurasiya, Ziqi Li, Rohit Medwal, Surbhi Gupta, John Rex Mohan, Yasuhiro Fukuma, Hironori Asada, Elbert E. M. Chia, Rajdeep Singh Rawat
Summary: This study demonstrates the electric field-mediated piezoelectric strain control of photogenerated THz spin current pulse from a multiferroic spintronic emitter, opening up new possibilities for the development of efficient on-chip THz spintronics devices.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Utkarsh Shashank, Angshuman Deka, Chen Ye, Surbhi Gupta, Rohit Medwal, Rajdeep Singh Rawat, Hironori Asada, X. Renshaw Wang, Yasuhiro Fukuma
Summary: This study focuses on the quasi-two-dimensional electron gas between insulating SrTiO3 and two types of aluminum-based amorphous insulators, and estimates their charge-to-spin conversion efficiency. The contribution of oxygen vacancy is investigated. A mechanism to explain the experimental results is proposed and a reliable method to estimate the thickness of the quasi-two-dimensional electron gas is developed. The findings show the significance of defects in charge-spin interconversion and offer a way to enhance it through defect engineering.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Masaaki Imamura, Hironori Asada, Yuya Kano, Ryota Matsuda, Daisuke Tashima, Jiro Kitagawa
Summary: We previously proposed that effective thermal-energy transfer in Bi:YIG LPE films occurs through enhanced SOC, and STE generation in Pt layer is increased by spin pumping from Bi:YIG film. However, we couldn't specifically relate the underlying mechanism to the driving force for spin current generation. In this paper, we discuss the origin of the driving force for increased spin currents through enhanced SOC in LPE YIG films.
Article
Physics, Applied
Sourabh Manna, Rohit Medwal, Surbhi Gupta, John Rex Mohan, Yasuhiro Fukuma, Rajdeep Singh Rawat
Summary: Ferromagnet/nonmagnet (FM/NM) bilayer-based spin Hall nano-oscillators (SHNOs) have potential for low-power physical reservoir computing systems. However, most studies require an external biasing magnetic field, limiting their practical implementation. This study demonstrates biasing field-free operation of a FM/NM bilayer-based SHNO using magnetic anisotropy control, which can significantly modify the auto-oscillation characteristics and reduce the threshold current for auto-oscillation.
APPLIED PHYSICS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Arun Jacob Mathew, John Rex Mohan, Ruoyan Feng, Rohit Medwal, Surbhi Gupta, Rajdeep Singh Rawat, Yasuhiro Fukuma
Summary: In this study, a spintronic device called spin Hall oscillator (SHO) is used as the reservoir in reservoir computing (RC) architecture. By evaluating the memory capacity of the SHO system with micromagnetic simulations, it is found that the reservoir's memory capacity is correlated with its efficiency in performing temporal tasks.
IEEE TRANSACTIONS ON MAGNETICS
(2023)
Article
Materials Science, Multidisciplinary
Utkarsh Shashank, Yoji Nakamura, Yu Kusaba, Takafumi Tomoda, Razia Nongjai, Asokan Kandasami, Rohit Medwal, Rajdeep Singh Rawat, Hironori Asada, Surbhi Gupta, Yasuhiro Fukuma
Summary: Recent studies have shown that incorporating nonmetallic lighter elements into 5d transition metals can enhance the efficiency of dampinglike torque. This finding is important for the development of low-power and robust magnetic memory.
Article
Physics, Multidisciplinary
Angshuman Deka, Bivas Rana, Ryo Anami, Katsuya Miura, Hiromasa Takahashi, YoshiChika Otani, Yasuhiro Fukuma
Summary: This study investigates the application of electric field controlled magnetization dynamics in low-power spintronic devices. Electric field induced parametric excitation was successfully achieved by using interfacial in-plane magnetic anisotropy. The excitation wavelength can be tuned by changing the input power and frequency of the applied voltage. A phenomenological model was developed to explain the role of electric field torque. This research offers an opportunity for developing nanoscale magnonic devices and exploring nonlinear dynamics in nanomagnetic systems.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Quantum Science & Technology
Utkarsh Shashank, Rohit Medwal, Taiga Shibata, Razia Nongjai, Joseph Vimal Vas, Martial Duchamp, Kandasami Asokan, Rajdeep Singh Rawat, Hironori Asada, Surbhi Gupta, Yasuhiro Fukuma
Summary: Efficient charge-spin interconversion is crucial for understanding the functionalities of spin-orbit torque in energy-efficient and high-speed spintronic devices. A new spin Hall material, Pt(S), is reported in this study, demonstrating significantly higher conversion efficiency compared to pristine Pt, along with large spin Hall angle and viable electrical and spin Hall conductivity.
ADVANCED QUANTUM TECHNOLOGIES
(2021)
