A5051894065- Magnetic properties of thin films
- Heusler alloys: electronic and magnetic properties
- Topological Materials and Phenomena
- Magnetic Properties and Applications
- Magnetic Properties of Alloys
- 2D Materials and Applications
- Magnetic and transport properties of perovskites and related materials
- Quantum and electron transport phenomena
- Graphene research and applications
- Physics of Superconductivity and Magnetism
- Multiferroics and related materials
- Advanced Condensed Matter Physics
- ZnO doping and properties
- Advanced Thermoelectric Materials and Devices
- Supramolecular Self-Assembly in Materials
- Magneto-Optical Properties and Applications
- MXene and MAX Phase Materials
- Metallic Glasses and Amorphous Alloys
- Rare-earth and actinide compounds
- Terahertz technology and applications
- Wireless Power Transfer Systems
- Gyrotron and Vacuum Electronics Research
- Magnetic Field Sensors Techniques
- Metallurgical and Alloy Processes
- Phase-change materials and chalcogenides
Max Planck Institute for Chemical Physics of Solids
2017-2024
University of Ioannina
2009-2024
Non-collinear antiferromagnets are revealing many unexpected phenomena and they became crucial for the field of antiferromagnetic spintronics. To visualize prepare a well-defined domain structure is key importance. The spatial magnetic contrast, however, remains extraordinarily difficult to be observed experimentally. Here, we demonstrate imaging technique based on laser induced local thermal gradient combined with detection anomalous Nernst effect. We employ this method in one most actively...
The magneto-thermoelectric properties of Heusler compound thin films are very diverse. Here, we discuss the anomalous Nernst response Co$_2$MnGa films. We systematically study coefficient as a function temperature, and show that unlike Hall effect, effect in strongly varies with temperature. exploit on-chip thermometry technique to quantify thermal gradient, which enables us directly evaluate coefficient. compare these results reference CoFeB film. 50-nm-thick exhibit large -2$\mu$V/K at 300...
Noncollinear antiferromagnets with a $D{0}_{19}$ ($\mathrm{space}\phantom{\rule{0.28em}{0ex}}\mathrm{group}=194$, $P{6}_{3}/mmc$) hexagonal structure have garnered much attention for their potential applications in topological spintronics. Here, we report the deposition of continuous epitaxial thin films such material, ${\mathrm{Mn}}_{3}\mathrm{Sn}$, and characterize crystal using combination x-ray diffraction transmission electron microscopy. Growth ${\mathrm{Mn}}_{3}\mathrm{Sn}$ both...
Topological magnetic semimetals promise large Berry curvature through the distribution of topological Weyl nodes or nodal lines and further novel physics with exotic transport phenomena. We present a systematic study structural magnetotransport properties ${\mathrm{Co}}_{2}\mathrm{MnGa}$ films from thin (20 nm) to bulklike behavior (80 in order understand underlying mechanisms role topology. The magnetron sputtered are $L{2}_{1}$-ordered showing very good heteroepitaxy strain-induced...
Noncollinear hexagonal antiferromagnets with almost zero net magnetization were recently shown to demonstrate giant anomalous Hall effect. Here, we present the structural and magnetic properties of noncollinear antiferromagnetic ${\mathrm{Mn}}_{3}\mathrm{Sn}$ thin films heteroepitaxially grown on Y:${\mathrm{ZrO}}_{2}$ (111) substrates a Ru underlayer. The crystallized in $D{0}_{19}$ structure $c$-axis preferred (0001) crystal orientation. are discontinuous, forming large islands...
The quantum Hall effect (QHE) is traditionally considered a purely two-dimensional (2D) phenomenon. Recently, three-dimensional (3D) version of the QHE has been reported in Dirac semimetal ZrTe5. It was proposed to arise from magnetic-field-driven Fermi surface instability, transforming original 3D electron system into stack 2D sheets. Here, we report thermodynamic, thermoelectric and charge transport measurements on ZrTe5 regime. measured thermodynamic properties: magnetization ultrasound...
Abstract Interacting electrons confined to their lowest Landau level in a high magnetic field can form variety of correlated states, some which manifest themselves Hall effect. Although such states have been predicted occur three-dimensional semimetals, corresponding response has not yet experimentally observed. Here, we report the observation an unconventional quantum limit bulk semimetal HfTe 5 , adjacent effect single electron band at low fields. The additional plateau-like feature...
We report a robust anomalous Nernst effect in Co2MnGa thin films the thickness regime between 20 and 50 nm. The coefficient varied range of -2.0 to -3.0 uV/K at 300 K. demonstrate that Hall coefficients exhibit similar behavior fulfill Mott relation. simultaneously measure all four transport longitudinal resistivity, transversal Seebeck coefficient, coefficient. connect values measured calculated conductivity by using remaining three magneto-thermal coefficients, where relation is still...
We report measurement of terahertz anomalous Hall conductivity and Faraday rotation in the magnetic Weyl semimetal ${\mathrm{Co}}_{2}\mathrm{MnGa}$ thin films as a function field, temperature, thickness, using time-domain spectroscopy. The shows thickness-independent around 600 ${\mathrm{\ensuremath{\Omega}}}^{\ensuremath{-}1}\phantom{\rule{0.16em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ at room it is also frequency-independent from 0.2--1.5 THz. magnitude longitudinal conductivities, weak...
The direct manipulation of spins via light may provide a path toward ultrafast energy-efficient devices. However, distinguishing the microscopic processes that can occur during laser excitation in magnetic alloys is challenging. Here, we study Heusler compound Co 2 MnGa, material exhibits very strong light-induced spin transfers across entire M-edge. By combining element specificity extreme ultraviolet high-harmonic probes with time-dependent density functional theory, disentangle...
Topological defects play a critical role across many fields, mediating phase transitions and macroscopic behaviors as they move through space. Their robust information carriers has also generated much attention. However, controlling their motion remains challenging, especially towards achieving along well-defined paths which typically require predefined structural patterning. Here we demonstrate the tunable, unidirectional of topological defects, specifically magnetic dislocations in weak...
Femtosecond laser light can transfer spin angular momentum between magnetic subspecies that exhibit hybridized valence bands within an alloy or compound, and represents the fastest route for manipulating magnetization of a material. To date, ultrafast has predominantly been explained in terms initial final states available excitation. Here, by comparing measured calculated dynamics across entire $M$-edges two very similar Heusler compounds, $Co_2MnGa$ $Co_2MnGe$ as well sample elemental Co,...
Various ${\mathrm{Co}}_{2}$-based Heusler compounds are predicted to be half-metallic ferromagnets with Weyl points. These systems lack of time inversion symmetry possess a momentum space Berry curvature that can introduce exotic transport properties. The present study, on epitaxially grown ${\mathrm{Co}}_{2}\mathrm{TiSn}$ films, is an approach understand and explore this possibility. theoretical investigation shows the significant for total anomalous Hall effect in experimentally films....
The cobalt-based Heusler alloys are promising for spintronic applications, thanks to their high spin polarization and half-metallic character. This work investigates the spin-dependent transport thermoelectric effects in epitaxial Co${}_{2}$TiSn thin films, with without V doping. anomalous Nernst angle Hall both determined, relationship between these two important parameters is discussed. These experimental results a step toward realizing spin-caloritronic devices efficient on-chip energy...
Spin chirality in metallic materials with non-coplanar magnetic order can give rise to a Berry phase induced topological Hall effect. Here, we report the observation of large effect high-quality films Mn$_{1.5}$PtSn that were grown by means magnetron sputtering on MgO(001). The resistivity is present up $\mu_{0}H \approx 4~$T below spin reorientation transition temperature, $T_{s}=185$~K. We find, maximum comparable magnitude as anomalous resistivity. Owing size, directly evident prior...
Magnetic Weyl semimetals are newly discovered quantum materials with the potential for use in spintronic applications. Of particular interest is cubic Heusler compound Co2MnGa due to its inherent magnetic and topological properties. This work presents structural, electronic properties of magnetron co-sputtered thin films, thicknesses ranging from 10 80 nm. Polarized neutron reflectometry confirmed a uniform magnetization through films. Hard x-ray photoelectron spectroscopy revealed high...
Record value of Curie temperature when the 2D van der Waals Fe 5− δ GeTe 2 , grown by molecular beam epitaxy, is interfaced with topological insulator Bi Te 3 .
Magnetic skyrmions and antiskyrmions are observed in material classes with different crystal symmetries, where the Dzyaloshinskii–Moriya interaction stabilizes either or antiskyrmions. Here, we report observation of two distinct peaks topological Hall effect a thin film Mn2RhSn. Utilizing phenomenological approach electronic transport simulations, these features attributed to be direct signatures topologically chiral spin objects, namely, Topological studies allow us determine existence...
Spintronic terahertz (THz) emitters based on the inverse spin Hall effect in ferromagnetic/heavy metal (FM/HM) heterostructures have become important sources for THz pulse generation. The design, materials, and control of these interfaces at nanometer level vital to engineer their emission properties. In this work, we present studies optimization such structures through a multi-pronged approach, taking advantage material interface engineering enhance spintronic emission. This includes...
Magnetic Weyl semimetals are an emerging material class that combines magnetic order and a topologically non-trivial band structure. Here, we study ultrafast optically driven spin injection from thin films of the Co2MnGa Co2MnAl into adjacent Pt layer by means terahertz emission spectroscopy. We find (i) efficient spin-current generators reaching efficiencies typical 3d-transition-metal ferromagnets such as Fe. (ii) The relaxation current provides estimate electron-spin time (170 fs) (100...
The process of medical education, particularly in the fast evolving new era metaschools, is a broad and complex issue. Harden & Crosby claimed that good teacher more than lecturer, identified 12 roles certify capable teacher. However, this only half truth: student listener. Teaching-and-learning not simply one-way process, and, as students are children, relationship between involves andragogy rather pedagogy. We therefore propose 12+1 student. SUMMARY OF WORK: paper was distributed class 90...
The study of heterogeneous reactions for enantiomeric processes based on inorganic crystals has been resurgent in recent years. However, the question remains how homochirality develops nature and chemical reactions. Here, successful growth B20 group PdGa single with different chiral lattices enabled us to achieve enantioselective recognition 3,4-dihydroxyphenylalanine (DOPA) a new mechanism, namely orbital angular momentum (OAM) polarization. textures indicate large OAM polarization near...
This study introduces a novel magnetic nanohybrid material consisting of ferromagnetic (FM) bcc Fe–Co nanoparticles (NPs) grown on nanodiamond (ND) nanotemplates. A combination wet chemistry, which produces chemical precursors and their subsequent thermal treatment under vacuum, was utilized for its development. The characterization the prepared samples performed with range specialized experimental techniques reveal that as-prepared hybrid annealing conditions leads to development Co-rich...
Abstract Half‐metallic half‐Heusler compounds with strong spin‐orbit‐coupling and broken inversion symmetry in their crystal structure are promising materials for generating absorbing spin‐currents, thus enabling the electric manipulation of magnetization energy‐efficient spintronic devices. In this work, spin‐to‐charge conversion sputtered MnPtSb within thickness ( t ) range from 1 to 6 nm is reported. A combination X‐ray transmission electron microscopy measurements evidence epitaxial...