Article
Engineering, Electrical & Electronic
Taiju Akushichi, Yota Takamura, Yusaku Shiotsu, Shuu'ichirou Yamamoto, Satoshi Sugahara
Summary: The spin injection phenomena of CoFe/MgO/Si tunnel contacts fabricated using radical oxidation and successive radical oxygen annealing were investigated. The effects of annealing condition on spin accumulation behavior in the Si channel were analyzed using Hanle-effect signals. The Hanle-effect signals could be decomposed into spin accumulation component and other phenomena component, with the ratio of spin component changing significantly depending on the annealing condition.
JOURNAL OF ELECTRONIC MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Nilay Maji, J. Panda, A. Santosh Kumar, T. K. Nath
Summary: In this study, efficient electrical spin injection and detection from NFO into p-Si via MgO tunnel barrier was achieved and proved to be promising. The use of oxide magnetic materials in spin injection and detection for room temperature spin-based electronic devices has been demonstrated.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2021)
Article
Chemistry, Physical
Keun-Hong Min, Duk Hyun Lee, Sang-Jun Choi, In-Ho Lee, Junho Seo, Dong Wook Kim, Kyung-Tae Ko, Kenji Watanabe, Takashi Taniguchi, Dong Han Ha, Changyoung Kim, Ji Hoon Shim, Jonghwa Eom, Jun Sung Kim, Suyong Jung
Summary: The authors investigate the tunnelling magnetoresistance in Fe3GeTe2/hBN(WSe2)/Fe3GeTe2 magnetic tunnel junctions and report strong variations including polarization reversals with bias. Using van der Waals heterostructures with two-dimensional magnets, they demonstrate electrically tunable spin injection and detection, as well as modulated and reversed net spin polarization of the injected carriers, leading to changes in tunnelling magnetoresistance. The authors attribute the spin polarization reversals to contributions from high-energy localized spin states in the metallic ferromagnet, which is inaccessible in conventional magnetic junctions.
Article
Materials Science, Multidisciplinary
L. Gladczuk, P. Dluzewski, K. Lasek, P. Aleshkevych, D. M. Burn, G. van der Laan, T. Hesjedal
Summary: In this study, layer-resolved ferromagnetic resonance was used to investigate the coupling between the magnetic layers of a Co/MgO/Permalloy magnetic tunnel junction, showing a strong interlayer interaction through the insulating MgO barrier. A theoretical model including exchange coupling and spin pumping was developed and fits to the experimental data were compared using a likelihood ratio test, providing unambiguous proof of the existence of interlayer coupling mediated by spin pumping.
Article
Materials Science, Multidisciplinary
A. Meo, S. Sampan-a-pai, P. B. Visscher, R. Chepulskyy, D. Apalkov, J. Chureemart, P. Chureemart, R. W. Chantrell, R. F. L. Evans
Summary: The study investigates the spin transfer torque switching dynamics in CoFeB/MgO/CoFeB magnetic tunnel junctions using atomistic simulations based on Slonczewski's model. The results demonstrate a magnetization reversal driven by the combination of coherent and nonuniform excitation modes, affected by factors such as current density, temperature, and structural imperfections. This deeper understanding can be valuable for spin transfer torque dynamics in nanoscale devices.
Article
Materials Science, Multidisciplinary
Ying Wang, Jiarong Yao, Shuaishuai Ding, Siyu Guo, Dapeng Cui, Xinyue Wang, Shuyuan Yang, Lijuan Zhang, Xinzi Tian, Di Wu, Chao Jin, Rongjin Li, Wenping Hu
Summary: Research on organic single crystals grown on a liquid substrate and used to construct single-crystalline OSVs revealed high magnetoresistance responses and spin transport properties. A magnetoresistance value as high as 17% was measured with an intermediate layer thickness of 269 nm. Spin transport was observed in single crystals up to a thickness of 457 nm, much larger than that of polycrystalline thin films.
SCIENCE CHINA-MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Wenbiao Zhang, Kequn Chi, Xiang Feng, Yinuo Shi, Zhou Li, Yun Xing, TieJun Zhou, Hao Meng, Bo Liu
Summary: Nitrogen doping in CoFe thin films can enhance the perpendicular magnetic anisotropy (PMA), but excess N doping can change the easy axis of magnetization to in-plane. The modulation of MAE through N doping and charge transfer between N and Co/Fe atoms contribute to the improvement of PMA in CoFe/MgO thin films.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Hui-Min Tang, Shi-Zhuo Wang, Xing-Tao Jia
Summary: We conducted a first-principles study on the tunneling anisotropic magnetoresistance (TAMR) in Ag(Ir,Pt)/MgO/Fe junctions. An enhanced TAMR effect of approximately 10% was found in these junctions at the equilibrium state, exhibiting ideal and skewed fourfold angular dependence for in-plane and out-of-plane TAMR, respectively. The TAMR effect showed a simple barrier thickness dependence, with the largest effect observed in the junction with a 6-monolayer MgO barrier. The complex and enhanced TAMR effect in these junctions is believed to be attributed to interfacial states induced by spin-orbit coupling, while even a slight interfacial oxygen vacancy disorder at the Fe/MgO interface can noticeably deteriorate the TAMR effect.
Article
Physics, Applied
Thomas Scheike, Qingyi Xiang, Zhenchao Wen, Hiroaki Sukegawa, Tadakatsu Ohkubo, Kazuhiro Hono, Seiji Mitani
Summary: Giant tunnel magnetoresistance (TMR) ratios were achieved in epitaxial Fe/MgO/Fe(001) exchange-biased spin-valve magnetic tunnel junctions by tuning growth conditions for each layer and growing on a highly (001)-oriented Cr buffer layer. Specific features include symmetric differential conductance spectra and plateau-like deep local minima in dI/dV.
APPLIED PHYSICS LETTERS
(2021)
Article
Materials Science, Multidisciplinary
J. Solano, O. Gladii, P. Kuntz, Y. Henry, D. Halley, M. Bailleul
Summary: In this study, broadband ferromagnetic resonance is measured in Fe films to investigate their magnetic properties. The films are sandwiched between MgO layers and their characteristics, such as exchange constant, cubic, uniaxial and surface anisotropies, are analyzed by studying the spin wave modes in applied magnetic fields and varying film thickness. Additional measurements of nonreciprocal spin-wave propagation allow for the separation of each interface contribution to the total surface anisotropy. The experimental results are consistent with the proposed model of a quasi-bulk film interior and two magnetically different interfaces.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Yuan Liu, Li Huang, Liying Wang
Summary: With the development of high-density, low-power-consumption, and multi-means regulation information storage devices, magnetic tunnel junctions (MTJs) with completely spin-polarized materials as electrodes have attracted much attention. Recent fabricated Heusler alloy Mn2.25Co0.75Ga0.5Sn0.5(MCGS) is a spin gapless semiconductor with 100% spin polarization and high Curie temperature of 725 K. Through density functional theory and non-equilibrium Green's function method, the spin-dependent electronic transport and photoelectric properties of MCGS/MgO/MCGS MTJs are investigated systematically. High tunnel magnetoresistance (TMR) is observed in MCGS/MgO/MCGS MTJs with various terminations, and the maximum TMR reaches 6.51 x 10^6%. The TMR value can be controlled and switched by applying a bias voltage, which is promising for designing magnetic logic devices. Additionally, the MCGS/MgO/MCGS MTJs exhibit perfect spin injection efficiency, and the switch of the spin channel can be controlled by the magnetization configuration of the ferromagnetic electrodes. Furthermore, by tailoring the polarization angle and photon energy of polarized light, nearly 100% spin-polarized photocurrent can be achieved. Linearly polarized light is more favorable than circularly polarized light for generating high spin-polarized photocurrent. These findings provide theoretical guidance for designing spin and optically tunable spintronic devices.
COMPUTATIONAL MATERIALS SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Xiaoyue Zhang, Ning Tang, Liuyun Yang, Chi Fang, Caihua Wan, Xingchen Liu, Shixiong Zhang, Yunfan Zhang, Xinqiang Wang, Yuan Lu, Weikun Ge, Xiufeng Han, Bo Shen
Summary: The spin injection into 2D electron gas in AlN/GaN heterostructures was studied, showing long spin relaxation time and the mechanism of spin injection. The results reveal the promising potential of 2DEG in AlN/GaN heterostructures for spin field-effect transistor applications.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Nilay Maji, Subhasis Shit, T. K. Nath
Summary: This article optimized the fabrication of a Ni0.65Zn0.35Fe2O4/MgO/p-Si heterostructure device using the PLD technique and experimentally investigated its structural, electrical, and magnetic features in the temperature range of 100-300 K. The results showed that the heterojunction exhibited positive junction magnetoresistance behavior under the application of an external magnetic field.
FRONTIERS IN MATERIALS
(2021)
Article
Engineering, Electrical & Electronic
Y. Zaoui, K. O. Obodo, L. Beldi, B. Bouhafs
Summary: Density functional theory was used to calculate the properties of Fe/MgO/Fe (001) magnetic tunnel junctions, highlighting the significant effects of interfacial oxygen atoms on the structural, magnetic, and electronic behavior of the system. The Fe/MgO/Fe structure exhibited metallic behavior with a Fe-O interface layer, and the polarization was found to be highly sensitive to the nature of the interface layer.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2021)
Article
Nanoscience & Nanotechnology
M. Stamenova, P. Stamenov, N. Baadji
Summary: We conducted first-principles spin-polarised quantum transport calculations in MgO-spaced magnetic tunnel junctions using two different Mn-based Heusler ferrimagnetic metals (Mn3Al and Mn3Ga). The results showed that Mn3Ga had a larger in-plane spin-transfer torque (STT) while STT in Mn3Al quickly disappeared away from the interface. On the other hand, the tunneling magneto-resistance (TMR) was practically 100% in Mn3Al-based MTJs and 60% in Mn3Ga case. The study suggests that Mn3Ga-Mn3Al solid solutions could lead to an optimal trade-off between STT and TMR in low-bias, low-temperature transport regime.
Article
Physics, Applied
Dae-Yun Kim, Min-Ho Park, Yong-Keun Park, Ji-Sung Yu, Joo-Sung Kim, Duck-Ho Kim, Byoung-Chul Min, Sug-Bong Choe
APPLIED PHYSICS LETTERS
(2018)
Article
Physics, Applied
Joo-Sung Kim, Yong-Keun Park, Hyun-Seok Whang, Jung-Hyun Park, Byoung-Chul Min, Sug-Bong Choe
APPLIED PHYSICS LETTERS
(2019)
Article
Engineering, Electrical & Electronic
Hee Sung Lee, Seung Hun Kim, Tae Hwan Jang, Hee-Gyum Park, Byoung-Chul Min, Seung-Young Park, Chul Soon Park
IEEE TRANSACTIONS ON MAGNETICS
(2019)
Article
Multidisciplinary Sciences
Daeseong Choe, Mi-Jin Jin, Shin-Ik Kim, Hyung-Jin Choi, Junhyeon Jo, Inseon Oh, Jungmin Park, Hosub Jin, Hyun Cheol Koo, Byoung-Chul Min, Seokmin Hong, Hyun-Woo Lee, Seung-Hyub Baek, Jung-Woo Yoo
NATURE COMMUNICATIONS
(2019)
Article
Materials Science, Multidisciplinary
Eun-Sang Park, Byoung-Chul Min, Hyun Cheol Koo, Kyoung-Whan Kim, Kyung-Jin Lee
CURRENT APPLIED PHYSICS
(2019)
Article
Multidisciplinary Sciences
Gyung-Min Choi, Jung Hyun Oh, Dong-Kyu Lee, Seo-Won Lee, Kun Woo Kim, Mijin Lim, Byoung-Chul Min, Kyung-Jin Lee, Hyun-Woo Lee
NATURE COMMUNICATIONS
(2020)
Article
Materials Science, Multidisciplinary
Yong-Keun Park, Joo-Sung Kim, Yune-Seok Nam, Seyyoung Jeon, Jung-Hyun Park, Kyoung-Whan Kim, Hyun-Woo Lee, Byoung-Chul Min, Sug-Bong Choe
NPG ASIA MATERIALS
(2020)
Article
Materials Science, Multidisciplinary
Hee Young Kwon, Kyung Mee Song, Juyoung Jeong, Ah-Yeon Lee, Seung-Young Park, Jeehoon Kim, Changyeon Won, Byoung-Chul Min, Hye Jung Chang, Jun Woo Choi
NPG ASIA MATERIALS
(2020)
Article
Multidisciplinary Sciences
Inseon Oh, Jungmin Park, Daeseong Choe, Junhyeon Jo, Hyeonjung Jeong, Mi-Jin Jin, Younghun Jo, Joonki Suh, Byoung-Chul Min, Jung-Woo Yoo
Summary: The molecule-based magnetic film for spin thermoelectric applications offers various synthetic routes, weak spin-lattice interaction, and low thermal conductivity, enabling effective energy harvesting from waste heat. By electrochemically depositing thin films on chromium electrodes at room temperature and demonstrating extremely low heat loss, this new class of magnet paves the way for sustainable recycling of ubiquitous waste heat.
NATURE COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Eun-Sang Park, Byoung-Chul Min, Hyun Cheol Koo, Kyoung-Whan Kim, Kyung-Jin Lee
Summary: This study theoretically investigates the spin-orbit torque on a ferromagnet within a ferromagnet(1)/normal metal/ferromagnet(2) trilayer, analyzing the effects caused by the spin Hall and spin swapping of ferromagnet(1). The results provide an analytical expression of the spin-orbit torque in trilayers, which may be valuable for quantifying the spin Hall and spin swapping effects of ferromagnets, and for interpreting SOT experiments using ferromagnets as spin current sources.
CURRENT APPLIED PHYSICS
(2021)
Article
Physics, Multidisciplinary
Hee-Gyum Park, Deok Hyun Yun, Won Min Jeong, OukJae Lee, Byoung-Chul Min
Summary: The study experimentally investigated the oscillatory interlayer exchange coupling (IEC) strength in synthetic antiferromagnets with various Ir/(Ru, Mo or W)/Ir composite spacers. It was found that the Ir insertion layer not only affects the magnitude of IEC but also the peak position in perpendicular synthetic antiferromagnets. The thickness dependence of composite spacers offers a possibility to tune both J(ex) and spacer thickness for SAF-based spintronic applications.
JOURNAL OF THE KOREAN PHYSICAL SOCIETY
(2021)
Article
Physics, Applied
Yune-Seok Nam, Dae-Yun Kim, Yong-Keun Park, Ji-Sung Yu, Seong-Hyub Lee, Duck-Ho Kim, Byoung-Chul Min, Sug-Bong Choe
Summary: Here, researchers propose an experimental scheme to determine the strength of the Heisenberg exchange interaction in ultrathin magnetic films. The scheme analyzes the chirality transition between different types of domain walls under an in-plane magnetic field and estimates the exchange stiffness constant based on this analysis. The scheme, which utilizes the magneto-optical Kerr effect, is applicable to ultrathin magnetic films down to a few atomic layers.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
Deok Hyun Yun, TaeHyuk Kwon, Ki-Hyuk Han, Dong Joon Lee, Seokmin Hong, Hyun Cheol Koo, Byoung-Chul Min, Byeong-Kwon Ju, OukJae Lee
Summary: In this study, the magnetic properties of Pt/CoFeB/MgO layers were investigated using the angle-resolved spin-torque ferromagnetic resonance method. The measurements provided reasonable magnetic parameters, but an unusual value was obtained for the interfacial spin transparency. The thickness dependence of the Lande g-factor for CoFeB indicated that the interfacial spin-orbit coupling played a role in determining the enhancement of magnetic damping. Furthermore, the azimuthal asymmetry in the magnetic system may not be related to unconventional spin polarization. These results contribute to the understanding of various magnetic properties and current-induced spin-torques in heavy-metal/ferromagnet bilayers.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Physics, Applied
Ji-Sung Yu, Dae-Yun Kim, Joon Moon, Seong-Hyub Lee, Jun-Young Chang, Duck-Ho Kim, Byoung-Chul Min, Sug-Bong Choe
Summary: Dzyaloshinskii-Moriya interaction (DMI) plays a crucial role in the formation and stability of chiral magnetic objects and also determines their roughness. Experimental observations on magnetic multilayer films reveal the relationship between DMI and the roughness of chiral domain-walls. This study provides a quantitative method to determine the DMI-induced effective field, which is an important parameter for the stability and dynamic characteristics of chiral domain-walls.
APPLIED PHYSICS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Dae-Yun Kim, Min-Ho Park, Yong-Keun Park, Joo-Sung Kim, Yune-Seok Nam, Duck-Ho Kim, Soong-Geun Je, Hyeok-Cheol Choi, Byoung-Chul Min, Sug-Bong Choe
NPG ASIA MATERIALS
(2018)