Transformation Texture Research Articles

Microstructure and properties of Al-4.8Cu-0.45Mn-0.19Cd-0.18Ti-0.17Zr-0.14V aluminum alloy extrusion bar

The mechanical properties, texture transformation, and mechanism of Al–Cu–Mn alloy during annealing were studied using three-dimensional orientation distribution function (ODF), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). The results showed that the increase in yield strength after annealing at 200 °C is due to the decrease in the proportion of P and M textures and the increase in the proportion of Goss texture. The increase in the change rate of mechanical properties observed during annealing at 250 and 350 °C can be attributed to the higher proportion of M and P textures and the reduced proportion of Goss textures. Among them, the proportion of M texture increased significantly, and the Goss texture decreased significantly after annealing at 350 °C. This is because the structural energy density (Ev) value of the Goss texture is higher than that of the M texture at 250 °C and 350 °C. The Goss texture is in an unstable state of high energy order. The deformed Goss texture is unstable at high temperatures, leading to conversion into M and other textures. The EBSD and TEM analysis revealed that the hardness is mainly related to the change in dislocation density. When the annealing temperature is increased from 250 to 350 °C, the hardness is significantly reduced from 62 HV to 52 HV, and the dislocation density is reduced from 4.0 × 1014 ρ/m−2 to 2.4 × 1014 ρ/m−2.

Enhancing microstructural integrity and mechanical performance of thick wire-arc directed energy deposited eutectic aluminum-silicon solid structure through continuous multi-pass friction stir processing

In wire-arc directed energy deposition (waDED), fabricating larger 3D components with single-layer tracks is challenging due to limitations in track thickness, requiring the development of bead overlapping strategies. However, fusion-based 3D-printed aluminum structures often show porosity and coarse-grained microstructures, limiting their industrial applications. To address these limitations, this study employs continuous multi-pass friction stir processing (FSP) on a waDED-produced aluminum block (140 mm × 150 mm × 28 mm). The severe plastic deformation induced by FSP triggers dynamic recrystallization (DRX), promoting the formation of equiaxed grains with an average grain size 8.75 times smaller than the as-fabricated waDED sample (67.03 μm vs 7.66 μm). Transmission Electron Microscopy (TEM) revealed decreased dislocation loops post-FSP, indicating DRX and dislocation annihilation. X-ray micro-computed tomography (X-CT) examination showed complete elimination of porosity in the waDED sample, owing to the intense mechanical stirring induced during FSP. Scanning electron microscopy (SEM) images of the waDED samples showed fibrous eutectic networks disrupted by FSP, leading to a uniform distribution of broken Si particles within the α-Al matrix. Hardness decreased by approximately 38 % (86 HV0.1 vs 53 HV0.1), while the average ultimate tensile strength decreased by about 4 % in the FSP-treated samples (159.19 MPa vs 153.02 MPa). Additionally, the formation of alpha fiber and weak cube texture components during FSP enhances ductility, as evidenced by a sixfold improvement in elongation (1.93 % vs 11.59 %). This textural transformation contributes to the characteristic deeper and more uniform dimples in the FSP-treated samples, indicative of ductile fracture, compared to the premature failure patterns in as-deposited samples.

3D-printed Ti6Al4V thoracic fusion cage: Biomechanical behavior and strengthening mechanism

To effectively replace diseased and damaged thoracic vertebrae, a series of three-dimensional (3D) printed titanium (Ti) alloy (Ti6Al4V) thoracic fusion cages with varying volume ratio of reinforced scaffolds are designed, and their structure-function relationships are investigated systematically. It is demonstrated that the mechanical strength of fusion cage is gradually enhanced as the scaffold volume increases, which may be attributed to its textural transformation from α phase to β phase. The compressive, shear, and fatigue of fusion cages successfully attain the International Organization for Standardization (ISO 23089), when the scaffold volume ratio exceeds 15%. Furthermore, the biomechanical analyses, including stress distributions and subsidence in flexion, extension, axial rotation, and lateral bending sections of fusion cages, further shed light on their potential clinical applications. This work deeply deciphers the intrinsic connection between biomechanical property and material texture of the thoracic fusion cages, offering valuable insights into their strengthening mechanism, which providing a guidance for the precise design and quick synthesis of other 3D-printed Ti6Al4V implants.

Field-free transformations of topological spin textures in ferrimagnetic TbFeCo films

The generation of topological spin textures under ultrafast laser pulse excitations and field-free manipulation of topological transitions between different spin textures has attracted enormous interest from the perspective of spintronic applications. Here, we utilize ultrafast electron microscopy to showcase the femtosecond laser pulses excitation on magnetic materials and have generated multiple topological spin textures in an amorphous ferrimagnetic TbFeCo film. Furthermore, the following field-free topological transitions between skyrmions and bubbles with diversified topology are identified via in situ heating the sample in Lorentz transmission electron microscopy. The critical role of uniaxial anisotropy variation on changing the magnetic textures during the heating process is confirmed by micromagnetic simulations. Our results provide a perspective on the generation and transformation of topological spin textures.

Weed Detection and Classification with Computer Vision Using a Limited Image Dataset

In agriculture, as precision farming increasingly employs robots to monitor crops, the use of weeding and harvesting robots is expanding the need for computer vision. Currently, most researchers and companies address these computer vision tasks with CNN-based deep learning. This technology requires large datasets of plant and weed images labeled by experts, as well as substantial computational resources. However, traditional feature-based approaches to computer vision can extract meaningful parameters and achieve comparably good classification results with only a tenth of the dataset size. This study presents these methods and seeks to determine the minimum number of training images required to achieve reliable classification. We tested the classification results with 5, 10, 20, 40, 80, and 160 images per weed type in a four-class classification system. We extracted shape features, distance transformation features, color histograms, and texture features. Each type of feature was tested individually and in various combinations to determine the best results. Using six types of classifiers, we achieved a 94.56% recall rate with 160 images per weed. Better results were obtained with more training images and a greater variety of features.

Development of a novel processing technique for cold-rolled Al-3 Mg aluminum alloys via athermally-enhanced electrical annealing

In this study, we proposed an alternative to the conventional warm forming processing for the softening of hard cold-rolled Al-3 wt% Mg aluminum alloys to improve formability. A novel processing technique was proposed via athermally-enhanced electrical annealing. The softening of the aluminum alloy to a maximum 48.2 % micro-hardness decrement at 158.5 °C was achieved via current-induced recrystallization at 4.0 × 104 A/cm2 and above for 1 h, as evidenced by the formation of strain-free equiaxial grains, the release of accumulated residual stress, the transformation of subboundaries and low-angle grain boundaries to high-angle grain boundaries, and the transformation of deformation texture to recrystallization texture. This study aims to provide a sustainable processing technique for the circular economy to achieve lower annealing temperature and energy consumption.

Influence of pre-stretching and annealing on microstructure and mechanical properties evolution of twin-roll cast Mg-2Al-1Zn-1Ca (wt.%) plates

Pre-stretching and annealing treatments were conducted on twin roll cast Mg-2Al-1Zn-1Ca (AZX211, in wt.%) plates with a rare earth-like texture. Varying amounts of deformation were applied along the rolling direction (RD) and transverse direction (TD) of AZX211 alloy in order to modify its mechanical properties at room temperature. The results demonstrate that pre-stretching treatment effectively enhances the yield strength (YS), especially along the RD. The strengthening mechanism is attributed to the production of a large number of dislocations and sub-grain boundaries, but the work-hardening ability of the plate will be greatly weakened. Additionally, annealing treatment substantially improves the plasticity and in-plane anisotropy and restores the work-hardening ability. The notable distinction in the pre-stretching process between different directions lies in the underlying deformation mechanism. In case of RD, deformation is predominantly governed by the slip mechanism of {0002} 〈11−20〉 basal slip and {10−10} 〈11−20〉 prismatic slip, while along the TD, deformation is primarily controlled by {0002} 〈11−20〉 basal slip without significant twinning deformation. When a 6 % pre-stretching is conducted, the initial rare earth-like texture of the sample transforms into a symmetrically distributed double-peak basal texture, accompanied by grain refinement. This texture transformation is chiefly due to the dominance of {0002} 〈11−20〉 basal slip-driven deformation. Moreover, the annealed sample maintains a strong basal texture, owing to strain-induced recrystallization.

Texture Analysis of Hot Rolled Martensitic and Bainitic Steels by Electron Backscatter Diffraction to Quantify Parent Austenite States

To measure textures of hot rolled martensitic and bainitic steels, electron backscatter diffraction (EBSD) is applied to large areas, each covering about a thousand of prior grains. A scanning step is selected to keep reasonable time of the data acquisition still providing in any grain a significant number of analyzed points. Contributions to the transformation texture appearing from deformation and recrystallization components of the parent texture are estimated with the Bain relationship. To assess the parent austenite state, their proportion is then expressed by a scalar parameter. The results are verified by independent metallographic data. Avoiding the reconstruction of prior grains, this statistical approach will facilitate evaluation of complex austenite structures with comparable fractions of dissimilar material states.

Microstructure and texture transformation of wedge-shaped rolled 3%Y2O3p/ZGK200 composites

The microstructure and texture transformation of 3%Y2O3p/ZGK200 composites after wedge-shaped rolling were investigated. The 3%Y2O3p/ZGK200 composites could be wedge-shaped rolled for 50 % reduction without obvious edge cracks. Basal <a> slip, prismatic <a> slip and pyramidal <c+a> slip detected by in-grain misorientation axes (IGMA) combined with Schmid factor (SF) analysis were abundantly activated during the whole rolling process. Different from the activation of all kinds of dislocation slips, many {10 1‾ 2} extension twins and few {101‾ 1}-{101‾ 2} secondary twins were activated with a reduction of 10 %. With increasing reduction from 30 % to 50 %, {101‾ 1}-{101‾ 2} secondary twins and {101‾ 1} compression twins started to play more important roles. Finally, the rolled deformed grains were elongated along rolling direction (RD) with abundant twins. During the whole rolling process, few recrystallized grains were found in the composites due to the effect of Gd addition. The {101‾ 2} extension twins whose c-axis oriented along normal direction (ND) should be attributed to the formation of basal texture, which was kept unchanged during the whole rolling process.

Segregation-induced abnormal recrystallization behavior, texture evolution, and effects on mechanical properties in twin-roll casting 2060 Al-Cu-Li alloys

Twin-roll casting (TRC) faces persistent segregation challenges limiting widespread use., Leveraging a comprehensive suite of techniques—electron probe microanalyzer (EPMA), electron back-scattered diffraction (EBSD), and transmission electron microscope (TEM)—and rooted in a thermo-mechanical-solute integrative simulation, this study focus on a detailed exposition of the structural evolution of the 2060 Al-Cu-Li alloy, encompassing its segregation tendencies and textural transformations throughout its processing trajectory. High and low-stress TRC scenarios, TRC-3 and TRC-6, are explored. Empirical observations ascertained that the TRC venture, particularly in TRC-3, cultivates a pronounced segregation gradient, a direct offshoot of the stress gradient, thereby inducing textural disparities. During the homogenization phase, the TRC structure with diminished segregation (TRC-6) manifested signs of recovery and sustained recrystallization, an environment amiable to compositional homogeneity and tempering the pre-existing segregation. In the terminal state, a pioneering discovery elucidated that heightened segregation precipitated the β-fiber textural enhancement mechanism—a phenomenon that deteriorates properties due to the discrepancy in segregation-induced hardness. With astutely managed segregation, TRC-6 recorded tensile strengths and elongation values of 563 MPa and 7.1% respectively, marking an increment by 20.0% and 208.7% in comparison to TRC-3. This research offers vital insights into solute gradients, providing a new perspective on gradient materials.

Laser‐Induced Real‐Space Topology Control of Spin Wave Resonances

AbstractFemtosecond laser excitation of materials exhibiting magnetic spin textures promises advanced magnetic control via the generation of non‐equilibrium spin dynamics. Ferrimagnetic [Fe(0.35 nm)/Gd(0.40 nm)]160 multilayers are used to explore this approach, as they host a rich diversity of magnetic textures from stripe domains at low magnetic fields, a dense bubble/skyrmion lattice at intermediate fields, and a single domain state for high magnetic fields. Using femtosecond magneto‐optics, distinct coherent spin wave dynamics are observed in this material in response to a weak laser excitation, enabling an unambiguous identification of the different magnetic spin textures. Moreover, employing strong laser excitation, versatile control of the coherent spin dynamics via non‐equilibrium transformation of magnetic spin textures becomes possible by both creating and annihilating bubbles/skyrmions. Micromagnetic simulations and Lorentz transmission electron microscopy with in situ optical excitation corroborate these findings.

Temperature dependent deformation behavior and texture evolution in AA6082 aluminum alloy: An integrated experimental and crystal plasticity simulation approach

This research provides a comprehensive analysis of the texture and temperature dependent deformation behavior of the aluminum alloy AA6082. The study is performed using a combination of experimental deformation tests and computational simulations using a crystal plasticity (CP) framework. The primary objective is to identify the critical influence of temperature on local stress states and dislocation density within the material during tensile tests. From an experimental perspective, the study employs ex-situ deformation tests and subsequent electron backscatter diffraction (EBSD) data in combination with energy dispersive x-ray spectrometer (EDS) analysis at 200 °C and 400 °C. The experimental EBSD data are adopted, preprocessed and converted into a geometry file for the numerical simulations. On the computational front, a dislocation density-based material model is adopted for CP simulations. The physical and fitting parameters of the model are calculated, adopted from the literature, or calibrated by comparing the global simulation results with experimental stress-strain observations under uniaxial tensile load at room temperature, 200 °C and 400 °C. Empirical functions for solid solution strengthening, dislocation density, fitting parameters controlling mean free path and dislocation annihilation have been derived that can be used to quickly interpolate them for any intermediate temperature. These functions combined with other model parameters can now be used for temperature-dependent CP modeling of AA6082. The isothermal grain-scale simulation and ex-situ experimental results confirmed a noteworthy texture transformation at higher temperatures, characterized by a reduction in the primary Cube orientation and its transition into a Copper orientation due to the stretching process. The correlation between the experimental results and the simulations on macro- and micro-scales is reasonable, indicating the accuracy and effectiveness of the CP approach in predicting the temperature dependent deformation behavior and texture evolution in aluminum alloys.

Deformation and Transformation Textures in the NaMgF3 Neighborite—Post-Perovskite System

The D″ region of the lower mantle, which lies just above the core–mantle boundary, is distinct from the bulk of the lower mantle in that it exhibits complex seismic heterogeneity and seismic anisotropy. Seismic anisotropy in this region is likely to be largely due to the deformation-induced texture (crystallographic preferred orientation) development of the constituent mineral phases. Thus, seismic anisotropy can provide a marker for deformation processes occurring in this dynamic region of the Earth. Post-perovskite-structured (Mg,Fe)SiO3 is believed to be the dominant mineral phase in many regions of the D”. As such, understanding deformation mechanisms and texture development in post-perovskite is important for the interpretation of observed seismic anisotropy. Here, we report on high-pressure diamond anvil cell deformation experiments on NaMgF3 neighborite (perovskite structure) and post-perovskite. During deformation, neighborite develops a 100 texture, as has been previously observed, both in NaMgF3 and MgSiO3 perovskite. Upon transformation to the post-perovskite phase, an initial texture of {130} at high angles to compression is observed, indicating that the {100} planes of perovskite become the ~{130} planes of post-perovskite. Further compression results in the development of a shoulder towards (001) in the inverse pole figure. Plasticity modeling using the elasto-viscoplastic self-consistent code shows this texture evolution to be most consistent with deformation on (001)[100] with some contribution of glide on (100)[010] and (001)&lt;110&gt; in NaMgF3 post-perovskite. The transformation and deformation mechanisms observed in this study in the NaMgF3 system are consistent with the behavior generally observed in other perovskite–post-perovskite systems, including the MgSiO3 system. This shows that NaMgF3 is a good analog for the mantle bridgmanite and MgSiO3 post-perovskite.

Manipulating the thermal stability of the {111}-oriented nanotwinned Ag films by ion bombardment

Materials with nanotwinned structures have been known to possess high strength, high ductility, and low resistivity. Tailoring their mechanical and thermal stabilities has become a critical technique based on their practical applications in the electronic industry. In this study, we propose to manipulate the thermal stability of the nanotwinned Ag thin films with the assistance of ion bombardment. The {111}-oriented nanotwinned Ag films were fabricated on Si (100) substrate with 100 nm-thick Ti adhesion layer using different applied ion bombardment energies. We found that the thermal stability of highly {111}-oriented nanotwinned Ag films can be tailored by using different levels of ion bombardment during deposition. The sample with the highest ion bombardment energy exhibits exceptional thermal stability, which can sustain {111}-oriented nanotwinned structure and high mechanical strength after 450 °C annealing. On the other hand, the {111} to {100} texture transformation with large grain coarsening can be triggered at low temperature of 150 °C without introducing ion bombardment during the deposition. This study not only advances the fundamental understanding of the thermal stability of the nanotwinned Ag films after high-temperature annealing but also provides valuable insights into manipulating the thermal stability of sputtered nanostructured Ag films through ion bombardment based on the demands of their applications.

Gold mineralisation by pyrite recrystallisation and arsenopyrite sequestration in the Jiaochong Au deposit, Tongling ore district, eastern China: Implications for the formation of stratabound ore deposits

The Middle–Lower Yangtze River Valley metallogenetic belt (MLYRB) is a large and economically valuable porphyry–skarn Cu–Au ore belt in China with a total reserve of >600 tonnes of gold. Orebodies in the MLYRB are commonly stratabound and extend for several tens of metres in length and locally for more than 1000 m. However, the origin of the stratabound orebodies is uncertain, with proposals including a magmatic or sedimentary genesis, and the specific processes by which these gold deposits were formed are also unclear. Here we report a study of the representative stratabound Jiaochong Au deposit in the Tongling ore district, where stratified gold orebodies are hosted at the Triassic -Permian strata boundary. A detailed field survey, petrologic observations, in situ sulfur isotopic analysis, and major and trace element compositional analysis of gold and sulfide grains were carried out to determine how the gold was enriched. Field survey shows that precipitated sulphides exhibit obvious mineral and textural zonation from wall-rock to orebody centres as follows: Zone 1, colloform pyrite (Py1) ± sphalerite ± chalcopyrite → Zone 2, euhedral pyrite (Py2) ± pyrrhotite + arsenopyrite ± colloform pyrite (Py1) → Zone 3, pyrrhotite + arsenopyrite. From zone 1 to zone 3, the sulphides were progressively phase-transformed, with the earlier Py1 being gradually consumed and converted into Py2, which finally became pyrrhotite. The gold deposition occurs in Zones 2 and 3 and forms two generations of gold grains, one group being completely enclosed within euhedral Py2 with low As contents (<0.1 wt%) and another group infilling fractures between arsenopyrite and pyrrhotite or occurring as inclusions within arsenopyrite with high As contents (0.4 to 1.4 wt%). The comparable S-isotope compositions of the ore sulfides to those of Mesozoic intermediate-felsic intrusions and the veining characteristics of colloform pyrite in the Tongling ore district suggest that Mesozoic magmatic-hydrothermal fluids, rather than Carboniferous sedimentary rocks as usually thought, provided the principal ore-forming materials. The gold precipitation in this study followed two continuous processes: recrystallisation and arsenopyrite sequestration; in the first process, Au is remobilised from the pyrite structure at higher temperatures up to recrystallisation of fine-grained, colloform morphologies into euhedral crystals and formation of Au-bearing metallic particles (Au1); with the ongoing recrystallisation more As is released and accumulated into the equilibrated fluids, forming As-rich pyrite or arsenopyrite and a second period of gold deposition (Au2). The continuous sulphide zonation texture and phase transformation, similar to Jiaochong, have been observed in other gold deposits in the MLYRB, and our gold enrichment processes may also give an explanation for the formation of these stratabound gold deposits.

Texture Analysis of Chinese Dried Noodles during Drying Based on Acoustic-Mechanical Detection Methods.

To better understand the textural transformation of Chinese dried noodles during the drying process, a convenient acoustic-force detection method was established. By comparing the breaking point, it was possible to determine the time-scale correlation between the force-displacement curves and acoustic spectrograms. The acoustic eigenvalues showed a consistent upward trend with the mechanical parameters during the drying process. With a wave crest reaching 152.8 dB and a signal maximum reaching 0.072, the structural stability of the dried noodles hardly induces a higher acoustic response. This suggests that the mechanical strength and rigidity of the dried noodles undergo minimal changes during this period. In comparison to the mechanical parameters, the acoustic eigenvalues accurately describe the changes in texture of dried noodles under various drying conditions, moreover, the sound threshold also provides a more effective response to the dried noodles' structural strength threshold. Therefore, the acoustic detection method can be applied to assist the conventional mechanical measurement in the field of the texture evaluation of dried food.

Multiomics analyses of the effects of LED white light on the ripening of apricot fruits

IntroductionApricot (Prunus armeniaca L.) fruits are highly perishable and prone to quality deterioration during storage and transportation. ObjectivesTo investigate the effects of LED white light treatment on postharvest ripening of fruits using metabolomics, transcriptomics, and ATAC-Seq analysis. MethodsFruits were exposed to 5 μmol m−2 s−1 LED white light for 12 h followed by 12 h of darkness at 20 °C daily for 12 days. The effects of the treatments on the physiological and nutritional quality of the fruits were evaluated. These data were combined with transcriptomic, metabolomic, and ATAC-Seq data from fruits taken on 8 d of treatment to provide insight into the potential mechanism by which LED treatment delays ripening. ResultsLED treatment activated pathways involved in ascorbate and aldarate metabolism and flavonoid and phenylpropanoid biosynthesis. Specifically, LED treatment increased the expression of UDP-sugar pyrophosphorylase (USP), L-ascorbate peroxidase (AO), dihydroflavonol 4-reductase (DFR), chalcone synthase (CHS), and caffeoyl-CoA O-methyltransferase (CCOAOMT1), leading to the accumulation of caffeoyl quinic acid, epigallocatechin, and dihydroquercetin and the activation of anthocyanin biosynthesis. LED treatment also affected the expression of genes associated with plant hormone signal transduction, fruit texture and color transformation, and antioxidant activity. The notable genes affected by LED treatment included 1-aminocyclopropane-1-carboxylate synthase (ACS), 1-aminocyclopropane-1-carboxylate oxidase (ACO), hexokinase (HK), lipoxygenase (LOX), malate dehydrogenase (MDH), endoglucanase (CEL), various transcription factors (TCP, MYB, EFR), and peroxidase (POD). ATAC-Seq analysis further revealed that LED treatment primarily regulated phenylpropanoid biosynthesis. ConclusionThe results obtained in this study provide insights into the effects of LED light exposure on apricot fruits ripening. LEDs offer a promising approach for extending the shelf life of other fruits and vegetables.

Alleviative effects of carboxymethyl chitosan on the quality deterioration of frozen rice dough during freeze thaw cycles

The objective of this study was to examine the impact of carboxymethyl chitosan (CMCh) on rice dough quality during freeze–thaw cycles (FTCs). We conducted a comprehensive analysis of frozen rice dough using various techniques, including scanning electron microscopy (SEM), low–field nuclear magnetic resonance (LF–NMR), confocal laser scanning microscopy (CLSM), Fourier transform infrared spectroscopy (FT–IR), size–exclusion high–performance liquid chromatography (SE–HPLC), small–angle X–ray scattering (SAXS), X–ray diffraction (X–RD), differential scanning calorimetry (DSC), and rapid visco–analysis (RVA). Our results revealed that adding carboxymethyl chitosan (CMCh) to frozen rice dough reduced damage to starch granules and gluten proteins during FTCs compared to dough without CMCh. This resulted in the deceleration of the modification of the ordered protein structure. Furthermore, the inclusion of CMCh resulted in increased cross–linking with the large protein polymer, impairing the capacity of bound water to transition into free water within the frozen rice dough. Consequently, this led to an elevation in the storage modulus (G′), effectively retarding the textural transformation of the frozen rice dough. Introducing CMCh to frozen rice dough subsequently decelerated the alterations in the short-range order and crystal structures of starch, consequently modifying the pasting and thermal properties of the frozen rice dough. Based on the results obtained from our experiments, CMCh has a decelerating effect on the impact of frozen rice dough on FTCs.

Ancient Glass Products Identification and Composition Analysis Based on Support Vector Machine

Studying the chemical composition and weathering-related properties of ancient glass holds immense significance as it served as a vital trading commodity along the early Silk Road in China. The texture transformations of ancient glass are closely linked to its chemical composition and storage conditions. Throughout the weathering process, internal elements continually interact with the surrounding environment, leading to alterations in their chemical proportions. To address this, this article has developed a classification method utilizing support vector machines for identifying glass types and analyzing their compositions. This article research provides archaeologists with a convenient tool for investigating ancient glasses, significantly enhancing the identification process.

Heat current-driven topological spin texture transformations and helical q-vector switching

The use of magnetic states in memory devices has a history dating back decades, and the experimental discovery of magnetic skyrmions and subsequent demonstrations of their control via magnetic fields, heat, and electric/thermal currents have ushered in a new era for spintronics research and development. Recent studies have experimentally discovered the antiskyrmion, the skyrmion’s antiparticle, and while several host materials have been identified, control via thermal current remains elusive. In this work, we use thermal current to drive the transformation between skyrmions, antiskyrmions and non-topological bubbles, as well as the switching of helical states in the antiskyrmion-hosting ferromagnet (Fe0.63Ni0.3Pd0.07)3P at room temperature. We discover that a temperature gradient {{{{{boldsymbol{nabla }}}}}}T drives a transformation from antiskyrmions to non-topological bubbles to skyrmions while under a magnetic field and observe the opposite, unidirectional transformation from skyrmions to antiskyrmions at zero-field, suggesting that the antiskyrmion, more so than the skyrmion, is robustly metastable at zero field.