Article
Nanoscience & Nanotechnology
Brahim Marfoua, Jisang Hong
Summary: The spin Seebeck effect was investigated in a 2D ferromagnetic CrPbTe3 layer, revealing insights into minority spin electron carriers and their impact on effective mass and deformation potential. The study also found dependencies on spin and carrier type in the electrical conductivity onset energy, with the majority spin carrier controlling effective spin and charge Seebeck coefficients in hole-doped systems, and the minority spin carrier in electron-doped systems. The maximum spin Seebeck coefficient obtained was 1320 muV/K at 50 K, with a reduced but still significant value of 715 muV/K at 100 K.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2021)
Article
Engineering, Electrical & Electronic
Ekkarat Pongophas, Yingyot Infahsaeng, Wasan Maiaugree, Santi Phumying, Rungrueang Pattanakul, Mati Horprathum, Chanunthorn Chananonnawathorn, Piyawat Piyasin, Supree Pinitsoontorn, Harihara Ramamoorthy, Ratchanok Somphonsane, Narit Faibut, Wanchai Pijitrojana, Paowarin Khayaiwong, Poramed Wongjom
Summary: In this article, a low-cost instrument for the versatile measurement of spin caloritronics phenomena is presented. The instrument uses solenoid coils to provide a uniform magnetic field and the sample is sandwiched between thermal baths in a vacuum chamber. The results show excellent magnetic field uniformity and stability of the generated temperature difference. The effectiveness of the instrument is verified through measurements of various spin caloritronics effects.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2023)
Article
Nanoscience & Nanotechnology
Ajay Partap Singh Rana, Chandan Bera
Summary: This paper systematically investigates 2D Janus monolayers based on CrX3 monolayers and discovers their high potential in spin caloritronics applications.
Article
Nanoscience & Nanotechnology
Dan-Dan Wu, Hua-Hua Fu
Summary: The study uncovers several exotic thermal spin-related transport properties of the narrowest zigzag graphene nanoribbons, including thermal colossal magnetoresistance effect, thermal negative differential resistance effect, spin-Seebeck effect, and spin-filtering effect, pushing carbon-based material candidates towards thermoelectric conversion device applications.
Article
Physics, Applied
Md Kamruzzaman, Shaojie Hu, Kohei Ohnishi, Takashi Kimura
Summary: In a laterally configured nano-spintronic device, the heat transport in a magnetic multi-layered nanowire was investigated by detecting second harmonic voltages. The magnetic-field dependence of the second harmonic voltage in the multi-layered wire shows a clear spin-valve-like effect, with a magnitude larger than the electrical spin valve effect. The second harmonic signal, along with its probe configuration dependence, is quantitatively explained by the spin-dependent Seebeck effect with a significant heat flow from the substrate, paving the way for precise analysis of heat flow in nano-structured electronic devices.
APPLIED PHYSICS EXPRESS
(2021)
Article
Materials Science, Multidisciplinary
S. S. Costa, L. C. Sampaio
Summary: This study reports on thermal phenomena related to the transport of magnons in insulating ferromagnetic systems and investigates the influence of magnon-phonon dissipation on magnon thermal conductivity and the spin Seebeck effect using Boltzmann's theory. The study also discusses the spin Peltier effect and highlights the relationship between the intensity of the effect and the magnetic layer thickness. The results are compared with experimental data for yttrium iron garnet (YIG) and bilayer YIG/Pt, showing good agreement between calculations and experiments.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Rinki Bhowmick, Sayantanu Koley, Mausumi Chattopadhyaya, Sabyasachi Sen
Summary: This study establishes a simple 2D tunnelling nanostructure created by an assembly of ferromagnetic g-C4N3 electrodes separated by insulating graphene sheet, as a potential spincaloritronic device. The system shows a large departure in up and down spin component of Seebeck coefficient, and the spin thermoelectric figure of merit is 10(3) times larger than the charge part. The emergence of spin polarized Seebeck coefficient may be attributed to intrinsic ferromagnetism of g-C4N3 and spin-injection from ferromagnetic electrode to insulating graphene. This widely varying spin polarized Seebeck coefficient is attributed to large negative slope of logarithmic transmission coefficient of spin up channel compared to spin down counterpart.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2021)
Article
Multidisciplinary Sciences
T. Kikkawa, D. Reitz, H. Ito, T. Makiuchi, T. Sugimoto, K. Tsunekawa, S. Daimon, K. Oyanagi, R. Ramos, S. Takahashi, Y. Shiomi, Y. Tserkovnyak, E. Saitoh
Summary: The article reports on a nuclear thermoelectric effect caused by nuclear spins in a solid, with low-temperature thermoelectric signals observed down to 100mK. The experiment and theoretical calculations demonstrate the potential for exploring thermoelectric science and technologies at ultralow temperatures.
NATURE COMMUNICATIONS
(2021)
Article
Multidisciplinary Sciences
Anand Manaparambil, Ireneusz Weymann
Summary: This paper investigates the spin-resolved thermoelectric properties of strongly correlated molecular structures in the linear response regime, showing a strong dependence of thermopower on the strength and type of the exchange interaction as well as the molecule's magnetic anisotropy. When coupled to ferromagnetic leads, an interplay between spin-resolved tunneling processes and intrinsic magnetic properties of the molecule is observed, with the system exhibiting the spin Seebeck effect in the case of finite spin accumulation in the leads. Additionally, a significant spin Seebeck effect can develop when the molecule exhibits an easy-plane magnetic anisotropy, and the sign of spin thermopower depends on the type and magnitude of the molecule's exchange interaction.
SCIENTIFIC REPORTS
(2021)
Article
Chemistry, Multidisciplinary
Shankar Prasad Mitra, Rinki Bhowmick, Ajit Biswas, Mausumi Chattopadhyaya, Sayantanu Koley, Sabyasachi Sen
Summary: The study of spin-polarized thermoelectric system shows the impact of spin on the Seebeck coefficient, with the spin Seebeck coefficient being significantly larger than the charge Seebeck coefficient. This paves the way for extending the application of devices to on-chip energy harvesting systems.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2022)
Article
Materials Science, Multidisciplinary
Koichi Oyanagi, Saburo Takahashi, Takashi Kikkawa, Eiji Saitoh
Summary: We have theoretically studied the spin Seebeck effect (SSE) in a bilayer system of normal metal (NM) and paramagnetic insulator (PI). By considering the spin-flip scattering through interfacial exchange coupling, we calculated the thermal spin pumping from PI to NM and backflow spin current from NM to PI using a linear response approach. Our results show the appearance of a finite spin current at the interface under a temperature difference between spins in NM and PI, which increases with the density of localized spin S. Additionally, our model successfully explains the experimentally observed reduction of paramagnetic SSE in Pt/Gd3Ga5O12 when the Zeeman energy is comparable to the thermal energy.
Article
Engineering, Multidisciplinary
Mohammed M. El-Banna, Adel Helmy Phillips, Ahmed Saeed Abdelrazek Bayoumi
Summary: Theoretical investigations of valley-spin caloritronic transport properties of ferromagnetic silicene superlattice under ac-field effect are conducted using the transfer matrix method at various frequencies. The study focuses on describing resolved thermoelectric parameters and reveals an oscillatory behavior in all investigated thermoelectric parameters, which may be due to photon-assisted tunneling. Improved power factors are observed and attributed to the quantum confinement effect. The findings suggest that ferromagnetic silicene superlattice shows promise for energy harvesting and cooling applications in nanodevices.
AIN SHAMS ENGINEERING JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Lin Huang, Yongjian Zhou, Hongsong Qiu, Hua Bai, Chong Chen, Weichao Yu, Liyang Liao, Tingwen Guo, Feng Pan, Biaobing Jin, Cheng Song
Summary: The inverse spin Hall effect (ISHE) has been investigated in Mn2Au/[Co/Pd] heterostructures, showing that the direction of the Neel vector has a significant impact on the ISHE signal. This finding not only expands the study of the Hall effect, but also enhances the flexibility of antiferromagnetic spintronics.
ADVANCED MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Shankar Prasad Mitra, Rinki Bhowmick, Ajit Biswas, Mausumi Chattopadhyaya, Sayantanu Koley, Sabyasachi Sen
Summary: This study reports the spin-polarized thermoelectric features in a pi-stacked system, where the Seebeck coefficient becomes fully spin-dependent and switches from positive to negative values with temperature. The spin Seebeck coefficient is nearly four times larger than the charge Seebeck coefficient, and the spin thermoelectric figure of merit rises significantly compared to the charge thermoelectric figure of merit. These results have implications for measuring pure spin current and on-chip energy harvesting systems.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2022)
Article
Materials Science, Multidisciplinary
Henan Fang, Gongzhao Li, Mingwen Xiao, Xudong Huang
Summary: We have studied the tunnel magneto-Seebeck (TMS) effect in magnetic tunnel junctions with a single-crystal barrier using our previously developed extending spintronic theory. The theory is based on optical methods, allowing for a better consideration of the periodicity and coherence of the tunneling process. The results show oscillations of the Seebeck coefficients with the barrier thickness, arising from the diffraction of tunneling electrons by the periodic potential of the single-crystal barrier. The magnitudes of the calculated Seebeck coefficients are consistent with experimental values of intrinsic Joule heating, and the influences of the ferromagnetic electrodes and barrier on the oscillations have been investigated.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2023)
Article
Physics, Applied
Michiyasu Mori, Sadamichi Maekawa
Summary: The study investigates a superconducting quantum interference device (SQUID) with 0- and pi-Josephson junctions (JJs), known as pi-SQUID, using the resistively shunted junction model. It demonstrates that the pi-SQUID exhibits half-integer Shapiro steps (SS) under microwave irradiation, making it a potential pi-qubit with spontaneous loop currents. The equivalence of 0- and pi-JJs is crucial for achieving the half-integer SS and realizing the pi-qubit.
APPLIED PHYSICS EXPRESS
(2021)
Article
Physics, Multidisciplinary
Hiroyuki Chudo, Masaki Imai, Mamoru Matsuo, Sadamichi Maekawa, Eiji Saitoh
Summary: The study demonstrates the observation of the angular momentum compensation temperature (TA) in ferrimagnets, determining it to be 240K in the Ho3Fe5O12 system. The increase of TA with Dy content is shown, with Ho1.5Dy1.5Fe5O12 corresponding to room temperature. Fe-57-NMR measurements are used to explore domain wall dynamics in HoIG, revealing an enhancement of NMR signal at TA due to increased domain-wall mobility.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2021)
Article
Nanoscience & Nanotechnology
Junji Fujimoto, Florian Lange, Satoshi Ejima, Tomonori Shirakawa, Holger Fehske, Seiji Yunoki, Sadamichi Maekawa
Summary: By utilizing response theory, the paper calculates the charge current vortex generated by spin pumping at a point-like contact in a system with Rashba spin-orbit coupling. The oscillatory behavior of the charge current as a function of distance from the spin pumping source is observed, which is supported by numerical simulations. The introduction of the SOC Hamiltonian on the lattice as the generator of the spin current is a significant aspect of their calculations.
Article
Engineering, Electrical & Electronic
Junji Fujimoto, Hiroshi Funaki, Wataru Koshibae, Mamoru Matsuo, Sadamichi Maekawa
Summary: Motivated by a recent experiment, this study examines the interaction between electric current vorticity and localized spins in FeGe devices, revealing three effects: the induction of an effective Zeeman field, a vorticity-induced Dzyaloshinskii-Moriya interaction, and a spin current driven by the vorticity gradient. These findings open up a new path for designing magnetic textures using structural settings.
IEEE TRANSACTIONS ON MAGNETICS
(2022)
Article
Physics, Applied
J. Puebla, Y. Hwang, S. Maekawa, Y. Otani
Summary: Surface acoustic waves (SAWs) are elastic waves propagating on the surface of solids with the amplitude decaying into the solid. SAWs can manipulate the magnetization states by magnetostriction and magnetoelastic effects. This review discusses the characteristics of SAW devices and their interaction with the magnetization in thin films.
APPLIED PHYSICS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Kei Yamamoto, Mingran Xu, Jorge Puebla, Yoshichika Otani, Sadamichi Maekawa
Summary: In this paper, a theoretical description of magnon-phonon interactions in multilayer structures containing a ferromagnetic thin film is presented. The formalism takes into account external magnetic fields in arbitrary directions and various types of acoustic waves, including Rayleigh and Love surface modes. By paying attention to the spatial profile of acoustic wave modes and deriving analytical expressions for effective coupling coefficients, the study successfully reproduces a strongly anisotropic and non-reciprocal linewidth observed in recent experiments of acoustic ferromagnetic resonance.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Physics, Multidisciplinary
Hakuto Suzuki, Guoqiang Zhao, Jun Okamoto, Shoya Sakamoto, Zhi-Yin Chen, Yosuke Nonaka, Goro Shibata, Kan Zhao, Bijuan Chen, Wen-Bin Wu, Fan-Hsiu Chang, Hong-Ji Lin, Chien-Te Chen, Arata Tanaka, Masaki Kobayashi, Bo Gu, Sadamichi Maekawa, Yasutomo J. Uemura, Changqing Jin, Di-Jing Huang, Atsushi Fujimori
Summary: The magnetic properties and electronic excitations of Ba1-xKx(Zn1-yMny)2As2, a new diluted magnetic semiconductor, were studied using x-ray magnetic circular dichroism (XMCD) and resonant inelastic x-ray scattering (RIXS) techniques. The findings revealed that Mn atoms are in a high-spin configuration of d5, but the net spin moment is reduced due to the presence of competing ferromagnetic and antiferromagnetic interactions between Mn ions. RIXS spectra showed broad peaks originating from d-d crystal field excitations of Mn ions. Comparison with Ga1-xMnxAs indicated that the ground state of Mn in Ba1-xKx(Zn1-yMny)2As2 consists of both charge-transferred electron configuration and pure configuration with free holes.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2022)
Article
Materials Science, Multidisciplinary
Hiroto Adachi, Naoshi Ikeda, Eiji Saitoh
Summary: In comparison to transport of spin polarization in ferromagnets, transport of electric polarization in ferroelectrics remains less explored. Taking an excitonic insulator model of electronic ferroelectricity as a prototypical example, we theoretically investigate the low-energy dynamics and transport of electric polarization by microscopically constructing the Ginzburg-Landau action. We show that, because of the scalar nature of the excitonic order parameter, only the longitudinal fluctuations are relevant to the transport of electric polarization. We also formulate the electric-polarization diffusion equation, in which the electric-polarization current is defined purely electronically without recourse to the lattice degrees of freedom.
Article
Materials Science, Multidisciplinary
Akimitsu Watanabe, Hiroto Adachi, Yusuke Kato
Summary: In this study, we theoretically analyze the contribution of superconducting fluctuations to spin Hall effects. The results show that in two-dimensional systems, superconducting fluctuations have a suppressive effect on the extrinsic spin Hall effect, but an enhancing effect on the intrinsic spin Hall effect.
Article
Materials Science, Multidisciplinary
Yutaka Yamamoto, Masanori Ichioka, Hiroto Adachi
Summary: This study investigates the antiferromagnetic spin Seebeck effect across the spin-flop transition using numerical simulations. The results show that the sign reversal of the spin Seebeck effect is controlled by the exchange coupling at the interface and the spin dephasing in the metal layer.
Article
Materials Science, Multidisciplinary
Yunyan Yao, Ranran Cai, See-Hun Yang, Wenyu Xing, Yang Ma, Michiyasu Mori, Yuan Ji, Sadamichi Maekawa, Xin-Cheng Xie, Wei Han
Summary: This study reports the experimental observation of half-integer Shapiro steps in a strong ferromagnetic Josephson junction, showing robustness in a wide temperature range. The formation of these steps is attributed to the coexistence of 0 and pi states in the NiFe junction. This conclusion is supported by high-resolution transmission electron microscopy characterization of the junction materials.
Article
Materials Science, Multidisciplinary
Junji Fujimoto, Wataru Koshibae, Mamoru Matsuo, Sadamichi Maekawa
Summary: The research demonstrates a Dzyaloshinskii-Moriya interaction driven by electric current vorticity, allowing for control of magnetic skyrmion creation and annihilation without an external magnetic field. The direction of the current and structural settings offer different possibilities for studying magnetic textures.
Article
Materials Science, Multidisciplinary
H. Chudo, M. Matsuo, S. Maekawa, E. Saitoh
Summary: Using the rotating nuclear quadrupole resonance (NQR) method, we observed the Barnett field, rotational Doppler effect, and Berry phase, and studied the different NQR line splittings in various setups. Analyzing these spectral structures allowed us to clarify the origins of NQR line splittings and discuss the relationship between rotational Doppler effect, Barnett field effect, and Berry phase. Additionally, we provided clear evidence of the differences between rotational Doppler effect and Barnett field, and the equivalence of Barnett field and Berry phase.
Article
Materials Science, Multidisciplinary
Takuya Taira, Yusuke Kato, Masanori Ichioka, Hiroto Adachi
Summary: Theoretical investigation into the vortex spin Hall effect revealed its strong similarity with the vortex Nernst/Ettingshausen effect. The calculated temperature dependence of the voltage signal due to the inverse vortex spin Hall effect showed significant enhancement by vortex fluctuations. This result not only provides a possible explanation for a peculiar peak in the spin Seebeck effect in a specific system, but also suggests new experiments using superconductors with strong fluctuations.
Article
Engineering, Electrical & Electronic
Shoya Sakamoto, Guoqiang Zhao, Goro Shibata, Zheng Deng, Kan Zhao, Xiancheng Wang, Yosuke Nonaka, Keisuke Ikeda, Zhendong Chi, Yuxuan Wan, Masahiro Suzuki, Tsuneharu Koide, Arata Tanaka, Sadamichi Maekawa, Yasutomo J. Uemura, Changqing Jin, Atsushi Fujimori
Summary: The study investigates the perpendicular magnetic anisotropy of a layered ferromagnetic semiconductor using angle-dependent X-ray magnetic circular dichroism measurements. The large magnetic anisotropy is attributed to the anisotropic distribution of Mn 3d electrons and the lifting of degeneracy of p-d(xz), d(yz) hybridized states.
ACS APPLIED ELECTRONIC MATERIALS
(2021)
