Publications by authors named "Tian Shang"

8 Publications

  • Page 1 of 1

Recent developments on the magnetic and electrical transport properties of FeRh- and Rh-based heterostructures.

J Phys Condens Matter 2022 Jan 13. Epub 2022 Jan 13.

East China Normal University, Shanghai 200241, China, Shanghai, 200062, CHINA.

It is fascinating how the binary alloy FeRh has been the subject of a vast number of studies almost solely for a single-phase transition. This is, however, reasonable, considering how various degrees of freedom are intertwined around this phase transition. Furthermore, the tunability of this phase transition-the large response to tuning parameters, such as electric field and strain-endows FeRh huge potential in applications. Compared to the bulk counterpart, FeRh in the thin-film form is superior in many aspects: Materials in thin-film form are often more technologically relevant in the first place; in addition, the substrates add extra dimensions to the tunability, especially when the substrate itself is multiferroic. Here we review recent developments on the magnetic and transport properties of heterostructures based on FeRh and its end-member Rh, with the latter providing a new route to exploiting spin-orbit interactions in functional spintronic heterostructures other than the more often employed 5d metals. The methods utilized in the investigation of the physical properties in these systems, and the design principles employed in the engineering thereof may conceivably be extended to similar phase transitions to other magnetic materials.
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http://dx.doi.org/10.1088/1361-648X/ac4b28DOI Listing
January 2022

A generalized machine learning approach for dissolved oxygen estimation at multiple spatiotemporal scales using remote sensing.

Environ Pollut 2021 Nov 6;288:117734. Epub 2021 Jul 6.

Environmental Monitoring Central Station of Shenzhen, Shenzhen 518000, China.

Dissolved oxygen (DO) is an effective indicator for water pollution. However, since DO is a non-optically active parameter and has little impact on the spectrum captured by satellite sensors, research on estimating DO by remote sensing at multiple spatiotemporal scales is limited. In this study, the support vector regression (SVR) models were developed and validated using the remote sensing reflectance derived from both Landsat and Moderate Resolution Imaging Spectroradiometer (MODIS) data and synchronous DO measurements (N = 188) and water temperature of Lake Huron and three other inland waterbodies (N = 282) covering latitude between 22-45 °N. Using the developed models, spatial distributions of the annual and monthly DO variability since 1984 and the annual monthly DO variability since 2000 in Lake Huron were reconstructed for the first time. The impacts of five climate factors on long-term DO trends were analyzed. Results showed that the developed SVR-based models had good robustness and generalization (average R = 0.91, root mean square percentage error = 2.65%, mean absolute percentage error = 4.21%), and performed better than random forest and multiple linear regression. The monthly DO estimates by Landsat and MODIS data were highly consistent (average R = 0.88). From 1984 to 2019, the oxygen loss in Lake Huron was 6.56%. Air temperature, incident shortwave radiation flux density, and precipitation were the main climate factors affecting annual DO of Lake Huron. This study demonstrated that using SVR-based models, Landsat and MODIS data could be used for long-term DO retrieval at multiple spatial and temporal scales. As data-driven models, combining spectrum and water temperature as well as extending the training set to cover more DO conditions could effectively improve model robustness and generalization.
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http://dx.doi.org/10.1016/j.envpol.2021.117734DOI Listing
November 2021

Recent progress on superconductors with time-reversal symmetry breaking.

J Phys Condens Matter 2020 Jul 28. Epub 2020 Jul 28.

Department of Physics, Zhejiang University, ZheDa Rd. 38, Hangzhou, Zhejiang, 310027, CHINA.

Superconductivity and magnetism are adversarial states of matter. The presence of spontaneous magnetic fields inside the superconducting state is,therefore, an intriguing phenomenon prompting extensive experimental and theoretical research. In this review, we discuss recent experimental discoveries of unconventional superconductors which spontaneously break time-reversal symmetry and theoretical efforts in understanding their properties. We discuss the main experimental probes and give an extensive account of theoretical approaches to understand the order parameter symmetries and the corresponding pairing mechanisms including the importance of multiple bands.
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http://dx.doi.org/10.1088/1361-648X/abaa06DOI Listing
July 2020

Laue three dimensional neutron diffraction.

Sci Rep 2019 Mar 18;9(1):4798. Epub 2019 Mar 18.

Technical University of Denmark, Copenhagen, Denmark.

This article presents a measurement technique and data analysis tool to perform 3D grain distribution mapping and indexing of oligocrystalline samples using neutrons: Laue three-dimensional neutron diffraction (Laue3DND). The approach builds on forward modelling used for correlation and multiple fitting of the measured diffraction spots relative to individual grains. This enables not only to identify individual grains, but also their position and orientation in the sample. The feasibility and performance of the Laue3DND approach are tested using multi-grain synthetic datasets from cubic (α-Fe) and tetragonal (YBaCuFeO) symmetries. Next, experimental results from two data sets measured at the FALCON instrument of Helmholtz-Zentrum Berlin are presented: A cylindrical alpha iron (α-Fe) reference sample with 5 mm diameter and 5 mm height, as well as a 2 mm layered perovskite (YBaCuFeO). Using Laue3DND, we were able to retrieve the position and orientation of 97 out of 100 grains from a synthetic α-Fe data set, as well as 24 and 9 grains respectively from the α-Fe and YBaCuFeO sample measured at FALCON. Results from the synthetic tests also indicate that Laue3DND is capable of indexing 10 out of 10 grains for both symmetries in two extreme scenarios: using only 6 Laue projections and using 360 projections with extremely noisy data. The precision achieved in terms of spatial and orientation resolution for the current version of the method is 430 μm and 1° respectively. Based on these results obtained, we are confident to present a tool that expands the capabilities of standard Laue diffraction, providing the number, position, orientation and relative size of grains in oligocrystalline samples.
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http://dx.doi.org/10.1038/s41598-019-41071-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6423297PMC
March 2019

Design of magnetic spirals in layered perovskites: Extending the stability range far beyond room temperature.

Sci Adv 2018 10 26;4(10):eaau6386. Epub 2018 Oct 26.

Laboratory for Multiscale Materials Experiments, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.

In insulating materials with ordered magnetic spiral phases, ferroelectricity can emerge owing to the breaking of inversion symmetry. This property is of both fundamental and practical interest, particularly with a view to exploiting it in low-power electronic devices. Advances toward technological applications have been hindered, however, by the relatively low ordering temperatures of most magnetic spiral phases, which rarely exceed 100 K. We have recently established that the ordering temperature of a magnetic spiral can be increased up to 310 K by the introduction of chemical disorder. Here, we explore the design space opened up by this novel mechanism by combining it with a targeted lattice control of some magnetic interactions. In Cu-Fe layered perovskites, we obtain values close to 400 K, comfortably far from room temperature and almost 100 K higher than using chemical disorder alone. Moreover, we reveal a linear relationship between the spiral's wave vector and the onset temperature of the spiral phase. This linear law ends at a paramagnetic-collinear-spiral triple point, which defines the highest spiral ordering temperature that can be achieved in this class of materials. On the basis of these findings, we propose a general set of rules for designing magnetic spirals in layered perovskites using external pressure, chemical substitutions, and/or epitaxial strain, which should guide future efforts to engineer magnetic spiral phases with ordering temperatures suitable for technological applications.
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http://dx.doi.org/10.1126/sciadv.aau6386DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6203228PMC
October 2018

Stretchable Spin Valve with Stable Magnetic Field Sensitivity by Ribbon-Patterned Periodic Wrinkles.

ACS Nano 2016 04 5;10(4):4403-9. Epub 2016 Apr 5.

Key Laboratory of Magnetic Materials and Devices & Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo 315201, People's Republic of China.

A strain-relief structure by combining the strain-engineered periodic wrinkles and the parallel ribbons was employed to fabricate flexible dual spin valves onto PDMS substrates in a direct sputtering method. The strain-relief structure can accommodate the biaxial strain accompanying with stretching operation (the uniaxial applied tensile strain and the induced transverse compressive strain due to the Poisson effect), thus significantly reducing the influence of the residual strain on the giant magnetoresistance (GMR) performance. The fabricated GMR dual spin-valve sensor exhibits the nearly unchanged MR ratio of 9.9%, magnetic field sensitivity up to 0.69%/Oe, and zero-field resistance in a wide range of stretching strain, making it promising for applications on a conformal shape or a movement part.
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http://dx.doi.org/10.1021/acsnano.6b00034DOI Listing
April 2016

[Relationships between characteristics of ground bryophyte communities and environmental factors in urban area of Chongqing, China].

Ying Yong Sheng Tai Xue Bao 2015 Oct;26(10):3145-52

The present study focused on bryophyte species composition, species diversity and the relationship between bryophyte communities and environmental factors in urban area of Chongqing City, by using biodiversity indices and the canonical correspondence analysis (CCA), based on the data of 44 plots. The results revealed that 86 species belonging to 43 genera and 25 families were found in saxicolous bryophyte communities, while 46 species belonging to 28 genera and 22 families were found in terricolous ones. The diversity indices of both saxicolous and terricolous bryophyte communities from campuses were higher than those of parks, natural scenic resorts, Jinyunshan National Nature Reserve. TWINSPAN classified saxicolous and terricolous bryophyte communities into three and two groups, respectively. CCA results showed canopy density was the major environmental factor of saxicolous bryophyte communities influencing bryophyte distribution in parks and campuses, whereas altitude, relative humidity and human disturbance were the major environmental factors in natural scenic resorts and nature reserve. Soil pH, canopy density and human disturbance were the major environmental factors in terricolous bryophyte communities in parks and campuses, whereas altitude, relative humidity and water content of the soil were the major environmental factors in those of natural scenic resorts and nature reserve.
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October 2015

Fermi surface reconstruction and multiple quantum phase transitions in the antiferromagnet CeRhIn5.

Proc Natl Acad Sci U S A 2015 Jan 5;112(3):673-8. Epub 2015 Jan 5.

Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou, Zhejiang 310058, China; Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China

Conventional, thermally driven continuous phase transitions are described by universal critical behavior that is independent of the specific microscopic details of a material. However, many current studies focus on materials that exhibit quantum-driven continuous phase transitions (quantum critical points, or QCPs) at absolute zero temperature. The classification of such QCPs and the question of whether they show universal behavior remain open issues. Here we report measurements of heat capacity and de Haas-van Alphen (dHvA) oscillations at low temperatures across a field-induced antiferromagnetic QCP (Bc0 ≈ 50 T) in the heavy-fermion metal CeRhIn5. A sharp, magnetic-field-induced change in Fermi surface is detected both in the dHvA effect and Hall resistivity at B0* ≈ 30 T, well inside the antiferromagnetic phase. Comparisons with band-structure calculations and properties of isostructural CeCoIn5 suggest that the Fermi-surface change at B0* is associated with a localized-to-itinerant transition of the Ce-4f electrons in CeRhIn5. Taken in conjunction with pressure experiments, our results demonstrate that at least two distinct classes of QCP are observable in CeRhIn5, a significant step toward the derivation of a universal phase diagram for QCPs.
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http://dx.doi.org/10.1073/pnas.1413932112DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4311814PMC
January 2015
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