A5039751435- Magnetic properties of thin films
- Magneto-Optical Properties and Applications
- Multiferroics and related materials
- Quantum and electron transport phenomena
- Magnetic and transport properties of perovskites and related materials
- Physics of Superconductivity and Magnetism
- X-ray Diffraction in Crystallography
- Advanced Condensed Matter Physics
- Engineering and Materials Science Studies
- Magnetic Properties and Applications
- Physics and Engineering Research Articles
- Ferroelectric and Piezoelectric Materials
- Mechanical and Optical Resonators
- Acoustic Wave Resonator Technologies
- Crystallization and Solubility Studies
- Characterization and Applications of Magnetic Nanoparticles
- Theoretical and Computational Physics
- Inorganic Fluorides and Related Compounds
- Magnetic Field Sensors Techniques
- Electronic and Structural Properties of Oxides
- ZnO doping and properties
- Solidification and crystal growth phenomena
- Surface and Thin Film Phenomena
- Civil and Structural Engineering Research
- Intermetallics and Advanced Alloy Properties
Bavarian Academy of Sciences and Humanities
2015-2024
Deutsche Nationalbibliothek
2022-2023
Institut für Technische und Angewandte Physik (Germany)
2023
University of Wuppertal
2023
Technical University of Munich
2017-2022
Walter de Gruyter (Germany)
2019-2022
München Klinik
2022
Indian Institute of Technology Madras
2020
Josef Meissner (Germany)
2019
Japan Science and Technology Agency
2017
We report anisotropic magnetoresistance in $\mathrm{Pt}|{\mathrm{Y}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$ bilayers. In spite of ${\mathrm{Y}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$ being a very good electrical insulator, the resistance Pt layer reflects its magnetization direction. The effect persists even when Cu is inserted between and ${\mathrm{Y}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$, excluding contribution induced equilibrium at interface. Instead, we show that originates from...
We experimentally investigate and quantitatively analyze the spin Hall magnetoresistance effect in ferromagnetic insulator/platinum insulator/nonferromagnetic metal/platinum hybrid structures. For insulator, we use either yttrium iron garnet, nickel ferrite, or magnetite for nonferromagnet, copper gold. The is theoretically ascribed to combined action of inverse platinum metal top layer. It therefore should characteristically depend upon orientation magnetization adjacent ferromagnet prevail...
Abstract Magnons are the elementary excitations of a magnetically ordered system. In ferromagnets, only single band low-energy magnons needs to be considered, but in ferrimagnets situation is more complex owing different magnetic sublattices involved. this case, low lying optical modes exist that can affect dynamical response. Here we show spin Seebeck effect (SSE) sensitive complexities magnon spectrum. The SSE caused by thermally excited dynamics converted voltage inverse Hall at interface...
We investigate the spin Hall magnetoresistance in thin film bilayer heterostructures of heavy metal Pt and antiferromagnetic insulator NiO. While rotating an external magnetic field easy plane NiO, we record longitudinal transverse resistivity layer observe amplitude modulation consistent with magnetoresistance. In comparison to on collinear ferrimagnets, is phase shifted by 90{\deg} its strongly increases magnitude field. explain observed field-dependence a comprehensive model taking into...
The manipulation of the ferromagnetic magnetization via electric fields is investigated in Ni/BaTiO3 hybrid structures. application an field to ferroelectric BaTiO3 induces elastic strain. In hybrids, this strain transferred into Ni layer, affecting its due inverse magnetostriction. Two approaches electrically alter are investigated. One approach exploits strain-induced change nickel magnetic coercivity, and allows for both reversible irreversible control. other based on domain effects...
The control of magnetic properties by means an electric field is important aspect in magnetism and magnetoelectronics. We here utilize magnetoelastic coupling ferromagnetic/piezoelectric hybrids to realize a voltage magnetization orientation at room temperature. samples consist polycrystalline nickel thin films evaporated onto piezoelectric actuators. these multifunctional are investigated temperature as function the controlled stress exerted actuator on Ni film. Ferromagnetic resonance...
We investigate yttrium iron garnet (YIG)/cobalt (Co) heterostructures using broadband ferromagnetic resonance (FMR). observe an efficient excitation of perpendicular standing spin waves (PSSWs) in the YIG layer when frequencies PSSWs and Co FMR line coincide. Avoided crossings are found modeled mutual pumping exchange torques. The is suppressed by a thin aluminum oxide (AlOx) interlayer but persists with copper (Cu) interlayer, agreement proposed model.
The ferrimagnetic spinel oxide ${\text{Zn}}_{x}{\text{Fe}}_{3\ensuremath{-}x}{\text{O}}_{4}$ combines high Curie temperature and spin polarization with tunable electrical magnetic properties, making it a promising functional material for spintronic devices. We have grown epitaxial thin films $(0\ensuremath{\le}x\ensuremath{\le}0.9)$ on MgO(001) substrates excellent structural properties both in pure Ar atmosphere an $\text{Ar}/{\text{O}}_{2}$ mixture by laser molecular beam epitaxy...
We experimentally study the spin dynamics in a gadolinium iron garnet single crystal using broadband ferromagnetic resonance. Close to ferrimagnetic compensation temperature, we observe ultrastrong coupling of clockwise and counterclockwise magnon modes. The magnon-magnon strength reaches almost 40% mode frequency can be tuned by varying direction external magnetic field. theoretically explain observed as arising from broken rotational symmetry due weak magnetocrystalline anisotropy. effect...
Antiferromagnetic materials have been proposed as new types of narrowband THz spintronic devices owing to their ultrafast spin dynamics. Manipulating coherently dynamics, however, remains a key challenge that is envisioned be accomplished by spin-orbit torques or direct optical excitations. Here, we demonstrate the combined generation broadband (incoherent) magnons and (coherent) at 1 in low damping thin films NiO/Pt. We evidence, experimentally through modeling, two excitation processes...
We show that the ferromagnetic anisotropy of a thin crystalline ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$ film can be manipulated in situ via application tunable stress. The stress is exerted by piezoelectric actuator, onto which cemented. strain sample quantified as function voltage applied to actuator using high-resolution x-ray diffraction, and corresponding evolution magnetic determined resonance spectroscopy. By this means, we are able directly correlate structural properties. experimental...
Using X-ray magnetic circular dichroism (XMCD) measurements, we explore the possible existence of induced moments in thin Pt films deposited onto ferrimagnetic insulator yttrium iron garnet (Y3Fe5O12). Such a proximity effect is well established for Pt/ferromagnetic metal heterostructures. Indeed, observe clear XMCD signal at L3 edge Pt/Fe bilayers, while no such can be discerned traces Pt/Y3Fe5O12 bilayers. Integrating signals allows to estimate an upper limit polarization
We study the temperature dependence of spin Hall magnetoresistance (SMR) in yttrium iron garnet/platinum hybrid structures via magnetization orientation dependent measurements. Our experiments show a decrease SMR magnitude with decreasing temperature. Using sensitivity to transport properties normal metal, we interpret our data terms angle platinum from 0.11 at room 0.075 10 K, while diffusion length and mixing conductance ferrimagnetic insulator/normal metal interface remain almost constant.
We study the spin Hall magnetoresistance effect in ferrimagnet/normal metal bilayers, comparing response collinear and canted magnetic phases. In phase, which sublattice moments are all aligned along same axis, we observe conventional magnetoresistance. contrast, changes sign. Using atomistic simulations x-ray absorption experiments, can understand these observations terms of field temperature dependent orientation on different sublattices. This enables a magnetotransport based investigation...
We systematically investigate the spin-pumping effect in a series of yttrium-iron-garnet (YIG)--platinum (Pt) bilayers, comparing both broadband ferromagnetic resonance and electrically detected experiments. infer effective spin-mixing conductance as function YIG Pt layer thickness from measurements on pure layers well bilayer YIG/Pt samples frequency range 2 to 20 GHz. In bare films, we determine Gilbert damping constant approximately $\ensuremath{\alpha}=0.001$. With an additional platinum...
Boolean logic is the foundation of modern digital information processing. Recently, there has been a growing interest in phenomena based on pure spin currents, which allow to move from charge gates. We study proof-of-principle device ferrimagnetic insulator Yttrium Iron Garnet (YIG), with Pt strips acting as injectors and detectors for nonequilibrium magnons. experimentally observe incoherent superposition magnons generated by different injectors. This allows implement fully functional...
We report on the growth of epitaxial ZnO thin films and ZnO-based heterostructures sapphire substrates by laser molecular beam epitaxy (MBE). first discuss some recent developments in laser-MBE such as flexible ultraviolet optics, infrared heating systems or use atomic oxygen nitrogen sources, describe technical realization our advanced system. Then we optimization deposition parameters for fluence substrate temperature buffer layers. The detailed structural characterization x-ray analysis...
Applications based on spin currents strongly rely the control and reduction of their effective damping transport properties. We here experimentally observe magnon mediated (angular) momentum through a 13.4-nm thin yttrium iron garnet film with full magnetic via spin-orbit torque. Above critical torque, fully compensated manifests itself as an increase conductivity by almost 2 orders magnitude. compare our results to theoretical expectations recently predicted current induced condensates...
We report the observation of current-induced spin torque resonance in yttrium iron garnet/platinum bilayers. An alternating charge current at $\mathrm{GHz}$ frequencies platinum gives rise to dc pumping and Hall magnetoresistance rectification voltages, induced by Oersted fields ac effect-mediated transfer torque. In ultrathin garnet films, we observe actuated magnetization dynamics which are significantly larger than those generated field. Spin torques thus efficiently couple currents also...
We report on experiments demonstrating coherent control of magnon spin transport and pseudospin dynamics in a thin film the antiferromagnetic insulator hematite utilizing two Pt strips for all-electrical injection detection. The measured signal at detector reveals an oscillation its polarity as function externally applied magnetic field. quantitatively explain our terms diffusive precession caused by easy-plane anisotropy Dzyaloshinskii-Moriya interaction. This experimental observation can...
We investigate the spin Hall magnetoresistance (SMR) at room temperature in thin-film heterostructures of antiferromagnetic insulating (0001)-oriented $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$ (hematite) and $\mathrm{Pt}$. measure their longitudinal transverse resistivities while rotating an applied magnetic field up to 17 T three orthogonal planes. For out-of-plane magnetotransport measurements, we find indications for a multidomain configuration whenever...
The precession of magnon pseudospin about the equilibrium pseudofield, latter capturing nature magnonic eigenexcitations in an antiferromagnet, gives rise to Hanle effect. Its realization via electrically injected and detected spin transport antiferromagnetic insulator demonstrates its high potential for devices as a convenient probe eigenmodes underlying interactions antiferromagnet. Here, we observe nonreciprocity signal measured hematite using two spatially separated platinum electrodes...
We have investigated the magnetic properties of a piezoelectric actuator/ferromagnetic semiconductor hybrid structure. Using GaMnAs epilayer as ferromagnetic and applying piezo stress along its [110] direction, we quantify anisotropy function voltage ${V}_{p}$ applied to actuator using anisotropic magnetoresistance techniques. As in substantially changes temperature $T$, ratio magnetoelastic magnetocrystalline anistropies can be tuned from approximately 1/4 4. Thus, GaMnAs/piezoelectric...
We measure the ordinary and anomalous Hall effect in a set of yttrium iron garnet$|$platinum (YIG$|$Pt) bilayers via magnetization orientation dependent magnetoresistance experiments. Our data show that presence ferrimagnetic insulator YIG leads to an like signature Pt, sensitive both Pt thickness temperature. Interpretation experimental findings terms spin indicates imaginary part mixing interface conductance $G_{\mathrm{i}}$ plays crucial role YIG$|$Pt bilayers. In particular, our suggest...