Influence of uniaxial anisotropy on the domain pinning fields of ferromagnetic Ga1−xMnxAs films

Lee, Sangyeop; Lee, Hakjoon; Yoo, Taehee; Lee, Sanghoon; Liu, X.; Furdyna, J. K.

doi:10.1063/1.3486210

Cited by 8 publications

(3 citation statements)

References 18 publications

(12 reference statements)

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“…The upward jumps, caused by the GaMnAs layer with negative ∆R, become systematically weaker as the field angle increases from 10° to 60°, at which they nearly disappear; and then begin to increase again as the field angle increases beyond 60°. Since the hysteresis in PHR is most narrow when the field is oriented along the easy axis 24 , 25 , from the behavior just described we conclude that the GaMnAs layer with negative ∆R has its magnetic easy axis near 60°, deviating about 15° from the [010] direction. This deviation provides a measure of the relative strengths of uniaxial anisotropy field Hu along and cubic anisotropy field Hc along one of the directions to be Hu/Hc = 0.50 for the GaMnAs layer with negative ∆R 26 .…”

Section: Resultsmentioning

confidence: 64%

Magnetization reversal in trilayer structures consisting of GaMnAs layers with opposite signs of anisotropic magnetoresistance

Lee

Bac

et al. 2018

Sci Rep

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Magnetization reversal in a GaMnAs trilayer system consisting of two GaMnAs layers separated by a Be-doped GaAs spacer was investigated by magnetotransport measurements. The rotation of magnetization in the two GaMnAs layers is observed as two abrupt independent transitions in planar Hall resistance (PHR). Interestingly, one GaMnAs layer manifests a positive change in PHR, while the other layer shows a negative change for the same rotation of magnetization. Such opposite behavior of the two layers indicates that anisotropic magnetoresistance (AMR) has opposite signs in the two GaMnAs layers. Owing to this opposite behavior of AMR, we are able to identify the sequence of magnetic alignments in the two GaMnAs layers during magnetization reversal. The PHR signal can then be decomposed into two independent contributions, which reveal that the magnetic anisotropy of the GaMnAs layer with negative AMR is predominantly cubic, while it is predominantly uniaxial in the layer with positive AMR. This investigation suggests the ability of engineering the sign of AMR in GaMnAs multilayers, thus making it possible to obtain structures with multi-valued PHR, that can be used as multinary magnetic memory devices.

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Section: Resultsmentioning

confidence: 64%

Magnetization reversal in trilayer structures consisting of GaMnAs layers with opposite signs of anisotropic magnetoresistance

Lee

Bac

et al. 2018

Sci Rep

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“…The energy difference between these minima can be obtained from Eq. ( 2 ) for the CCW rotation, as follows: where and represent the domain pinning energies that occur in the CCW rotation when the current is positive and negative, respectively 28 , 35 ; and angles and indicate magnetization directions in the 2nd and 3rd quadrants before and after the transition across the barrier.…”

Section: Resultsmentioning

confidence: 99%

Quantitative determination of spin–orbit-induced magnetic field in GaMnAs by field-scan planar Hall measurements

Park

Lee

et al. 2021

Sci Rep

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Spin–orbit-induced (SOI) effective magnetic field in GaMnAs film with in-plane magnetic anisotropy has been investigated by planar Hall effect measurements. The presence of SOI field was identified by a shift between planar Hall resistance (PHR) hystereses observed with positive and negative currents. The difference of switching fields occurring between the two current polarities, which is determined by the strength of the SOI field, is shown to depend on the external field direction. In this paper we have developed a method for obtaining the magnitude of the SOI fields based on magnetic free energy that includes the effects of magnetic anisotropy and the SOI field. Using this approach, the SOI field for a given current density was accurately obtained by fitting to the observed dependence of the switching fields on the applied field directions. Values of the SOI field obtained with field scan PHR measurements give results that are consistent with those obtained by analyzing the angular dependence of PHR, indicating the reliability of the field scan PHR method for quantifying the SOI-field in GaMnAs films. The magnitude of the SOI field systematically increases with increasing current density, demonstrating the usefulness of SOI fields for manipulation of magnetization by current in GaMnAs films.

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“…This finding confirms that H pin is not constant. Instead, it is not only relevant to [1 1 0] (or [1 1 0]) uniaxial anisotropy and temperatures [21,30], but also strongly sensitive to the temperature. We then conclude that the decrease of external field causes the rising of pinning field, which decreases with the increase of temperature.…”

Section: Resultsmentioning

confidence: 99%

Quantitative determination of [0 1 0] uniaxial anisotropy and the pinning energy in (Ga,Mn)As films

Song¹,

Lin²,

Li³

et al. 2014

Semicond. Sci. Technol.

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A number of recent magnetization and transport studies show a rich spectrum of magnetic anisotropies of prototypical diluted magnetic semiconductors (Ga,Mn)As. However, few investigations thus far have provided the quantitative determination of [0 1 0] uniaxial magnetic anisotropy (UMA) and the domain-wall pinning field, which are commonly overshadowed by strong cubic anisotropy and huge Zeeman energy. Here we combine results of planar Hall effect experiments carried out at low magnetic fields, and calculations via a modifying Stoner-Wohlfarth model to address this issue. The results of this work indicate that the strength of [0 1 0] UMA constant can be unexpectedly large, even twice as large as that of [1 1 0] UMA, which differs drastically from the often accepted view that the former is only one tenth of the latter in magnitude. We also obtain quantitative values of the pinning field, which is not constant as expected. Instead, it decreases with increasing temperature or external field. These findings would fulfil the complete picture on magnetic anisotropies of (Ga,Mn)As.

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Influence of uniaxial anisotropy on the domain pinning fields of ferromagnetic Ga1−xMnxAs films

Abstract: Articles you may be interested inQuantitative analysis of the angle dependence of planar Hall effect observed in ferromagnetic GaMnAs film

Cited by 8 publications

References 18 publications

Magnetization reversal in trilayer structures consisting of GaMnAs layers with opposite signs of anisotropic magnetoresistance

Magnetization reversal in trilayer structures consisting of GaMnAs layers with opposite signs of anisotropic magnetoresistance

Quantitative determination of spin–orbit-induced magnetic field in GaMnAs by field-scan planar Hall measurements

Quantitative determination of [0 1 0] uniaxial anisotropy and the pinning energy in (Ga,Mn)As films

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