Anomalous behavior of spin-wave resonances in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ga</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mi>−</mml:mi><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Mn</mml:mi></mml:mrow><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mi mathvariant="normal">As</mml:mi></mml:math>thin films

Rappoport, Tatiana G.; Redlinski, Pawel; Liu, X.; Zaránd, Gergely; Furdyna, J. K.; Jankó, Boldizsár

doi:10.1103/physrevb.69.125213

Cited by 52 publications

(41 citation statements)

References 39 publications

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“…A more than an order of magnitude experimental scatter and a lack of any clear trend as a function of Mn doping can be found in the previous literature for the Gilbert damping and spin stiffness constants (Supplementary Note 3) [19][20][21][22][23][24][25][26][27][28] . Significant variations can be also found in the experimental magnetic anisotropy constants of (Ga,Mn)As (ref.…”

Section: Resultsmentioning

confidence: 94%

The essential role of carefully optimized synthesis for elucidating intrinsic material properties of (Ga,Mn)As

et al. 2013

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(Ga,Mn)As is at the forefront of spintronics research exploring the synergy of ferromagnetism with the physics and the technology of semiconductors. However, the electronic structure of this model spintronics material has been debated and the systematic and reproducible control of the basic micromagnetic parameters and semiconducting doping trends has not been established. Here we show that seemingly small departures from the individually optimized synthesis protocols yield non-systematic doping trends, extrinsic charge and moment compensation, and inhomogeneities that conceal intrinsic properties of (Ga,Mn)As. On the other hand, we demonstrate reproducible, well controlled and microscopically understood semiconducting doping trends and micromagnetic parameters in our series of carefully optimized epilayers. Hand-in-hand with the optimization of the material synthesis, we have developed experimental capabilities based on the magneto-optical pumpand-probe method that allowed us to simultaneously determine the magnetic anisotropy, Gilbert damping and spin stiffness constants from one consistent set of measured data.

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Section: Resultsmentioning

confidence: 94%

The essential role of carefully optimized synthesis for elucidating intrinsic material properties of (Ga,Mn)As

et al. 2013

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“…These peaks represent resonances of different spin-wave (SW) modes. In thin ferromagnetic samples SW modes are expected to occur at resonance fields H n [15,24,25]:…”

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confidence: 99%

Magnetoelectric Coupling in Single CrystalCu2OSeO3Studied by a Novel Electron Spin Resonance Technique

et al. 2012

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The magneto-electric (ME) coupling on spin-wave resonances in single-crystal Cu2OSeO3 was studied by a novel technique using electron spin resonance combined with electric field modulation. An external electric field E induces a magnetic field component µ0H i = γE along the applied magnetic field H with γ = 0.7(1) µT/(V/mm) at 10 K. The ME coupling strength γ is found to be temperature dependent and highly anisotropic. γ(T ) nearly follows that of the spin susceptibility J M (T ) and rapidly decreases above the Curie temperature Tc. The ratio γ/J M monotonically decreases with increasing temperature without an anomaly at Tc. PACS numbers: 75.85.+t, 76.50.+g, Magneto-electric (ME) materials exhibiting coupled and microscopically coexisting magnetic (M) and electric (P) polarizations have attracted considerable interest in recent years [1][2][3][4]. This coupling allows one to influence the magnetic state of a ME material via an external electric field, thus opening a broad range of possible technical applications of such materials [3,5]. Moreover, it is very interesting to investigate the microscopic mechanism of ME coupling, since P and M tend to exclude each other [4]. In order to detect the ME effect, sensitive and reliable experimental techniques are required, since this coupling is generally quite small. Usually, for the determination of the ME coupling either the dielectric properties of ME materials are measured as a function of magnetic field or the magnetization is studied as a function of an applied electric field [3].Cu 2 OSeO 3 is a paraelectric ferrimagnetic material with a Curie temperature of T c 57 K [6][7][8]. The ME effect in Cu 2 OSeO 3 was first observed by magnetocapacitance experiments [6]. Later on, a small abrupt change of the dielectric constant below T c was reported by infrared reflection and transmission studies [9,10]. Recent µSR investigations showed a rather small change of the internal magnetic field by applying an electric field [8]. X-ray diffraction [6] and nuclear magnetic resonance [11] studies revealed no evidence of any lattice anomaly below T c , suggesting that lattice degrees of freedom are not directly involved in the ME effect. Moreover, a metastable magnetic transition with enhanced magnetocapacitance was observed [6] and later on was also investigated under hydrostatic pressure [12]. Very recently, ME skyrmions were observed in Cu 2 OSeO 3 by means of Lorentz transmission electron microscopy [13] and small angle neutron scattering [14].Here we report a study of the ME coupling in single crystal of Cu 2 OSeO 3 . For this investigation a novel microscopic method for the direct determination of the ME effect based on the standard FMR/EPR technique combined with electric field modulation was developed. As a result, to our knowledge for the first time spin-wave resonance (SWR) excitations [15] were detected via ME coupling. The linear ME coupling strength γ was determined quantitatively in Cu 2 OSeO 3 . In particular, the temperature and angular dependence of γ and the SWR...

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“…(5) the following value of the effective exchange stiffness constant D e f f = 80.1 meV·Å 2 is calculated. This value is two times larger than the one obtained for (Ga, Mn)As films [39] but it is only about one-third value measured for bulk Fe (280 meV·Å 2 ) [41].…”

Section: Resultsmentioning

confidence: 39%

“…9 -11 the SWR spectra for samples 1, 2 and 4 in the out-of-plain orientation (θ = 90°) of the magnetic field are presented. The insets show the dependence of H n on the spin wave number n. Surprisingly, the resonance fields of SWR modes in these samples vary linearly with n. Such dependence has been seen previously in Ga 1−x Mn x As thin films [38][39][40]. The origin of the anomalous spin wave dispersion has been attributed to the dependence of magnetic parameters inside the film on the distance from the surface.…”

Section: Resultsmentioning

confidence: 67%

Ferromagnetic and spin wave resonances in thin layer of expanded austenite phase

Typek

Guskos²,

Żołnierkiewicz

et al. 2014

Materials Science-Poland

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Four samples of austenite coatings deposited by reactive magnetron sputtering on silicon substrate at four different temperatures and pressures were investigated by ferromagnetic resonance (FMR) method at room temperature. The expanded austenite phase S (γ N ) layers with thickness in the 160 -273 nm range and concentration of magnetic atoms: 72 % Fe, 18 % Cr and 10 % Ni, were obtained. The coatings with nanometric size grains were strongly textured and grown mostly in [100] direction, perpendicular to the sample surface. Intense FMR spectra were recorded at various angles between the static magnetic field direction and the sample surface. A strong magnetic anisotropy of the main uniform FMR mode was observed and the effective magnetization 4πM e f f determined. Spin wave resonance (SWR) modes were observed in all investigated samples in out-of-plane geometry of the magnetic field. The resonance fields of SWR modes in our samples varied linearly with the spin wave mode number. The value of the effective magnon stiffness constant was determined assuming a parabolic shape of the magnetization variation across the sample thickness.

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Anomalous behavior of spin-wave resonances inGa1−xMnxAsthin films

Cited by 52 publications

References 39 publications

The essential role of carefully optimized synthesis for elucidating intrinsic material properties of (Ga,Mn)As

The essential role of carefully optimized synthesis for elucidating intrinsic material properties of (Ga,Mn)As

Magnetoelectric Coupling in Single CrystalCu2OSeO3Studied by a Novel Electron Spin Resonance Technique

Ferromagnetic and spin wave resonances in thin layer of expanded austenite phase

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