Polar Kerr effect studies of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi mathvariant="normal">Ga</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">Mn</mml:mi><mml:mi>x</mml:mi></mml:msub><mml:mi mathvariant="normal">As</mml:mi></mml:mrow></mml:math>epitaxial films

Lang, Rudi; Winter, Andreas; Pascher, H.; Krenn, H.; Liu, X.; Furdyna, J. K.

doi:10.1103/physrevb.72.024430

Cited by 50 publications

(67 citation statements)

References 29 publications

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“…Generally speaking, these observations are consistent with the previous studies of (Ga,Mn)As ternary alloys where several authors have reported a moderate dependence of the MO properties on the Mn concentration. 11,25,26,30,31,34 It is worth mentioning that the spectral dependence of the magneto-optical Kerr effect obtained using the 40-band k.p model in (Ga,Mn)(As,P) is in much better agreement with experimental results than in ternary (Ga,Mn)As using the 30-band k.p model. 30 We believe that the more accurate description of the MOKE originates from a better description of the bands with our 40-band k.p model in particular, from a good determination of the BS details over a wide range of k-vectors in four directions.…”

Section: Moke Spectrasupporting

confidence: 72%

“…These values are consistent with previous reports in (Ga,Mn)As compounds. 25,26,29,30,32,57 Let us note however that their respective amplitudes depend on the layer thickness (Eq. (3)).…”

Section: Moke Spectramentioning

confidence: 99%

“…6,18,19 Magneto-optical microscopy uses the MOKE to gain insight into the magnetic domains static pattern 7,20,21 and the domain wall dynamics. 22 While the MO effects in (Ga,Mn)As have been extensively investigated, [13][14][15][16][23][24][25][26][27][28][29][30][31][32][33][34] the MO properties of (Ga,Mn) (As,P) thin films, more specifically the interplay between the Mn doping and P substitution, remain to be investigated. Hence, in the present study, we report on the MOKE in the interband transition range for ferromagnetic (Ga,Mn)(As,P) samples with different P and Mn contents.…”

Section: Introductionmentioning

confidence: 99%

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Magneto-optical Kerr spectroscopy of (Ga,Mn)(As,P) ferromagnetic layers: Experiments and k.p theory

Yahyaoui

Riahi

Maaref

et al. 2017

Journal of Applied Physics

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We present a theoretical and experimental study of the magneto-optical properties of thin (Ga,Mn) (As,P) layers on GaAs substrates with varying phosphorus fractions. Using a 40-band k.p model as well as an antiferromagnetic (s, p)-d exchange interaction, we calculate the dielectric tensor, the Kerr rotation angle, and the ellipticity in the interband transition region. Our calculations are validated through a set of accurate comparisons with experimental results. The Kerr ellipticity peak is found to be 2 to 3 times larger than the Kerr rotation angle both experimentally and theoretically. This work will enable to optimize the magneto-optical effects in these layers for maximum sensitivity in ultra-fast magnetization dynamics and domain microscopy experiments. Published by AIP Publishing.

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Section: Moke Spectrasupporting

confidence: 72%

“…These values are consistent with previous reports in (Ga,Mn)As compounds. 25,26,29,30,32,57 Let us note however that their respective amplitudes depend on the layer thickness (Eq. (3)).…”

Section: Moke Spectramentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Magneto-optical Kerr spectroscopy of (Ga,Mn)(As,P) ferromagnetic layers: Experiments and k.p theory

Yahyaoui

Riahi

Maaref

et al. 2017

Journal of Applied Physics

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“…Final states in the dispersionless level close to the bottom of the conduction band were proposed. 30 It has also been argued that most of the magnetooptical spectrum of GaMnAs at ∼1.6 eV is dominated by transitions involving the intra-gap states. 15,32 Our findings support these interpretations, as our calculations of magnetooptical spectra of GaMnAs using the k·p band model 31 agree qualitatively with the published measurements 15,29 only for a very low hole concentration, p ∼ 10 19 cm −3 , which disagrees with the critical temperatures of most of the measured samples.…”

Section: Interpretation and Theoretical Modelingmentioning

confidence: 99%

Femtosecond demagnetization and hot-hole relaxation in ferromagneticGa1−xMnxAs

et al. 2008

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We have studied ultrafast photoinduced demagnetization in GaMnAs via two-color time-resolved magneto-optical Kerr spectroscopy. Below-bandgap midinfrared pump pulses strongly excite the valence band, while near-infrared probe pulses reveal sub-picosecond demagnetization that is followed by an ultrafast (∼1 ps) partial recovery of the Kerr signal. Through comparison with InMnAs, we attribute the signal recovery to an ultrafast energy relaxation of holes. We propose that the dynamical polarization of holes through p-d scattering is the source of the observed probe signal. These results support the physical picture of femtosecond demagnetization proposed earlier for InMnAs, identifying the critical roles of both energy and spin relaxation of hot holes.

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“…For typical magnetic materials, the critical frequencies to fully rotate the magnetization from in-plane to perpendicular-to-plane orientation are inaccessibly high: ϳ 200 GHz for Permalloy with M s ϳ 1000 emu/ cm 3 and D ϳ 4, and ϳ 4 GHz for a GaMnAs film 13 with M s ϳ 15 emu/ cm 3 and D ϳ 4. However, to identify the Barnett effect, it is sufficient to observe small changes in the z component of the magnetization: M z =− / ␥D.…”

Section: ͑10͒mentioning

confidence: 99%

Barnett effect in thin magnetic films and nanostructures

Bretzel

Bauer

Tserkovnyak³

et al. 2009

Applied Physics Letters

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The Barnett effect refers to the magnetization induced by rotation of a demagnetized ferromagnet. We describe the location and stability of stationary states in rotating nanostructures using the Landau-Lifshitz-Gilbert equation. The conditions for an experimental observation of the Barnett effect in different materials and sample geometries are discussed. © 2009 American Institute of Physics. ͓doi:10.1063/1.3232221͔At the dawn of quantum mechanics, the Barnett 1,2 effect-magnetization induced by rotation-confirmed that magnetization is associated with angular momentum. Furthermore, Barnett measured the gyromagnetic ratio of electrons in ferromagnets and the anomalous g factor of the electron for the first time. The Barnett effect can be understood in terms of a rotating gyroscopic wheel, that aligns itself with the axis of rotation until a stationary state in the rotating frame of reference is achieved. Since angular momentum L is associated with magnetization M =−␥L, with ␥ = g B / ប = g͉e͉ / 2m being the gyromagnetic ratio, mechanical rotation induces a net magnetization antiparallel to the axis of rotation. The torque acting on the magnetization in the rotating frame of reference is equivalent to a torque due to the presence of a gauge magnetic fieldThere has recently been a renewed interest in the coupling of magnetization with mechanical motion, for example in mechanically detected ferromagnetic resonance spectroscopy measurements.3 A nanomagnetomechanical system consisting of a cantilever and a thin magnetic film shows coupled magnetovibrational modes. 4,5 Furthermore, the nanomechanical current-driven spin-flip torque at the normalmetal/ferromagnet interface of a suspended nanowire has been detected. 6 In Barnett's original experiments, rotation frequencies of Շ 500 Hz generated a change of the magnetic field of the order of 10 −4 G in macroscopic samples. Although in nanostructures detecting such small fields may become more challenging, a range of powerful techniques have recently been developed, which could be utilized for the purpose. To date, very small changes in the magnetization can be measured using the magneto-optical Kerr effect, Faraday spectroscopy, superconducting quantum interference devices or Hall micromagnetometry.7 Therefore, we present here a theoretical feasibility study of the Barnett effect in magnetic thin films and nanostructures. Our focus is the dynamics in magnetic thin films and nanoclusters, which we study by means of the Landau-Lifshitz-Gilbert ͑LLG͒ equation for the magnetization vector m,where H eff is the effective magnetic field, m is the unit vector of magnetization, and ␣ the dimensionless damping constant. We can separate the dynamics caused by the rotation of the system as a whole from the dynamics in the rotating frame of reference by the transformation m = R͑͒m R and H eff = R͑͒H eff R , where R͑͒ is a unitary matrix describing the rotation by a time-dependent angle ͑t͒ around the axis of rotation and m R ͑H eff R ͒ denote the magnetization ͑effective magnetic fiel...

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Polar Kerr effect studies ofGa1−xMnxAsepitaxial films

Cited by 50 publications

References 29 publications

Magneto-optical Kerr spectroscopy of (Ga,Mn)(As,P) ferromagnetic layers: Experiments and k.p theory

Magneto-optical Kerr spectroscopy of (Ga,Mn)(As,P) ferromagnetic layers: Experiments and k.p theory

Femtosecond demagnetization and hot-hole relaxation in ferromagneticGa1−xMnxAs

Barnett effect in thin magnetic films and nanostructures

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