Davit Petrosyan


Last Name

Petrosyan

First Name

Davit

ORCID

0009-0007-7446-2952

Organisational unit

03986 - Gambardella, Pietro / Gambardella, Pietro

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Publications 1 - 3 of 3
  • Implementation of field-differential phase-resolved microwave magnetic spectroscopy
    Item type: Journal Article
    Legrand, William; Petrosyan, Davit; Wang, Hanchen; et al. (2025)
    Review of Scientific Instruments
    Microwave spectroscopies are central to the investigation of magnetic systems by enabling the identification of dynamical resonance modes and by providing quantitative information on key magnetic parameters. Experiments on magnetization dynamics based on inductive microwave techniques usually rely on either field-modulated power detection or phase-resolved detection using a vector network analyzer. While these two approaches bring separate advantages, they have rarely been combined together. In this work, we develop customized microwave instrumentation combining phase-resolved detection and magnetic field modulation to perform microwave spectroscopy of magnetic systems. We apply this technique to ferromagnetic resonance (FMR), where it enables a quantitative measurement of the magnetic susceptibility in systems with small volume and magnetization. This method of field-differential phase-resolved microwave magnetic spectroscopy is compared with other approaches and is shown to greatly improve the resolution of finely separated FMR peaks and the detection of small signals. Furthermore, we model and characterize comprehensively the inductive coupling of the magnetic system to the microwave circuit, which enables a quantitative analysis of the resonance peaks and the rejection of potential errors originating from too strong permeability, imperfect impedance matching, broadening induced by field inhomogeneity, and varying sample placement.
  • Lattice-tunable Substituted Iron Garnets for Low-temperature Magnonics
    Item type: Journal Article
    Legrand, William; Kemna, Yana; Schären, Stefan; et al. (2025)
    Advanced Functional Materials
    The synthesis of nm-thick epitaxial films of iron garnets by physical vapor deposition has opened up exciting opportunities for the on-chip generation and processing of microwave signals encoded in magnons. However, iron garnet thin films suffer from demanding lattice-matching and stoichiometry requirements. Here a new approach to their synthesis is developed, enabling a precise and continuous tuning of iron garnet compositions based on the co-sputtering of binary oxides. By substituting a controlled proportion of iron with additional yttrium, Y3(YxFe5–x)O12 films of high crystalline quality are obtained, combining a widely tunable lattice parameter and excellent magnetization dynamics. This enables iron garnet thin films suited for cryogenic applications, which have long remained impractical due to microwave losses caused by paramagnetic garnet substrates. Low-temperature ferromagnetic resonance confirms the elimination of substrate paramagnetic losses for Y3(YxFe5–x)O12 films lattice-matched to Y3Sc2Ga3O12 (YSGG), a diamagnetic substrate. The Y3(YxFe5–x)O12 system can be matched to other substrates such as (Gd, Y)3Sc2Ga3O12. Bi-substituted films of (Bi0.8Y2.2)Fe5O12 also have ideal lattice matching to YSGG, demonstrating the versatility of this approach. This opens unprecedented options for cation substitutions in iron garnet films, offering a promising avenue to new properties and quantum magnonic devices operating in low-temperature environments.
  • Orbital Pumping in Ferrimagnetic Insulators
    Item type: Journal Article
    Wang, Hanchen; Kang, Min-Gu; Petrosyan, Davit; et al. (2025)
    Physical Review Letters
    We report the detection of pure orbital currents generated by both coherent and thermal magnons in the magnetic insulator Bi-doped yttrium iron garnet (BiYIG). The pumping of orbital and spin currents is jointly investigated in nanodevices made of naturally oxidized Cu, pure Cu, Pt, and Cr. The absence of charge conduction in BiYIG and the negligible spin-to-charge conversion of oxidized Cu allows us to disambiguate the orbital current contribution. Comparative measurements on YIG and BiYIG show that the origin of the orbital pumping in BiYIG/oxidized Cu is the dynamics of the orbital magnetization in the magnetic insulator. In Cr, the pumping signal is dominated by the negative spin Hall effect rather than the positive orbital Hall effect, indicating that orbital currents represent a minority of the total angular momentum current pumped from the magnetic insulator. Our results also evidence that improving the interfacial transparency significantly enhances pumping efficiencies, not only for spin but also for orbital currents.
Publications 1 - 3 of 3