Exchange Anisotropy in Epitaxial

Yang, Chih-Yen; Lai, Chih‐Huang; Huang, Sheng-Huang; Huang, Hsin-Erh; Bor, Hui‐Yun

doi:10.1109/tmag.2006.879155

Cited by 4 publications

(1 citation statement)

References 8 publications

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“…In the case of sputter-deposited AF thin films, understanding the exchange-bias phenomenon quantitatively is complicated because of the microstructure. For example, AF polycrystalline fcc IrMn thin films are widely used in commercial devices, usually with a strong degree of preferred out-of-plane (1 1 1) orientation [11][12][13][14][15]. However, in the plane of the film, the crystallographic orientation does not have a high degree of order resulting in a high density of grain boundaries.…”

Section: Introductionmentioning

confidence: 99%

Exchange bias in epitaxial Fe/Ir_0.2Mn_0.8bilayers grown on MgO (0 0 1)

Wang¹,

Köhn²,

Wang³

et al. 2009

J. Phys. D: Appl. Phys.

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Exchange bias has been studied in epitaxial Fe/Ir0.2Mn0.8 (IrMn) bilayers grown by molecular beam epitaxy on MgO (0 0 1) substrates. The IrMn layer has a chemically disordered fcc structure with an epitaxial relationship of MgO(0 0 1)[1 1 0]//Fe(0 0 1)[1 0 0]//IrMn(0 0 1) [1 1 0]. In this system, exchange bias is induced during growth at room temperature without post-annealing, by applying a small magnetic field, HA, along the bcc Fe [1 0 0] easy axis. The temperature dependence of the exchange bias field and the coercivity along the Fe [1 0 0] easy axis, measured up to approximately half the Néel temperature, shows an exponential decay of these parameters with increasing temperature. The magnetization measured as a function of applied field along the Fe [1 0 0] easy axis results in a negatively shifted hysteresis loop, typical for exchange bias, while when the magnetic field is applied along the Fe [0 1 0] easy axis (perpendicular to HA), a symmetric double-shifted loop is observed. In both cases, the magnetization reversal occurs through two successive events involving nucleation and propagation of domains in which the magnetic moments are perpendicular to each other. We demonstrate that due to the epitaxial growth of the IrMn layer, the unidirectional anisotropy induced by exchange bias is aligned with one of the Fe easy axis directions and, in effect, is added to the four-fold cubic anisotropy of the Fe layer.

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Section: Introductionmentioning

confidence: 99%

Exchange bias in epitaxial Fe/Ir_0.2Mn_0.8bilayers grown on MgO (0 0 1)

Wang¹,

Köhn²,

Wang³

et al. 2009

J. Phys. D: Appl. Phys.

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Reorientation of exchange anisotropy in epitaxial (002) IrMn/CoFe system

Huang

Yang

Lai

2009

Journal of Applied Physics

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We investigated the reorientation of exchange anisotropy in the epitaxial (002) IrMn/CoFe bilayers. Transitions of exchange-bias field from a negative field to a positive field with increasing time scale were observed at room temperature. The negatively magnetized state combining with the strong magnetocrystalline anisotropy of CoFe may raise the probability that the interfacial spins of thin IrMn layers were thermally relaxed to the direction of CoFe magnetization; therefore, after a period of time, the exchange-bias direction was reversed. This process can be further enhanced when samples were placed under the setting field. The double-shifted magnetization curve observed in this system was used as a good indicator for the relaxation of interfacial spins of IrMn.

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Asymmetric double-shifted characteristics in epitaxial (002) exchange-biased IrMn/CoFe bilayers

Huang

Yang

Lin

et al. 2011

Applied Physics Letters

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Symmetric and asymmetric double-shifted loops were observed at room temperature in epitaxial (002) Ir20Mn80/Co50Fe50 samples placed in a setting field applied along collinear and noncollinear directions with the deposition-field direction, respectively. A coherent rotation model with extra unidirectional exchange and uniaxial anisotropies induced by the noncollinear setting field is proposed to explain the asymmetric double-shifted loops. Due to the existence of the biaxial magnetocrystalline anisotropy, the noncollinear setting field results in two interfacial Ir20Mn80 spin orientations, where the major spins determine the direction to observe double-shifted loops and the minor spins determine the field-shift and the asymmetry of double-shifted loops.

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Exchange Anisotropy in Epitaxial

Cited by 4 publications

References 8 publications

Exchange bias in epitaxial Fe/Ir_0.2Mn_0.8bilayers grown on MgO (0 0 1)

Exchange bias in epitaxial Fe/Ir_0.2Mn_0.8bilayers grown on MgO (0 0 1)

Reorientation of exchange anisotropy in epitaxial (002) IrMn/CoFe system

Asymmetric double-shifted characteristics in epitaxial (002) exchange-biased IrMn/CoFe bilayers

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Exchange Anisotropy in Epitaxial

Cited by 4 publications

References 8 publications

Exchange bias in epitaxial Fe/Ir0.2Mn0.8bilayers grown on MgO (0 0 1)

Exchange bias in epitaxial Fe/Ir0.2Mn0.8bilayers grown on MgO (0 0 1)

Reorientation of exchange anisotropy in epitaxial (002) IrMn/CoFe system

Asymmetric double-shifted characteristics in epitaxial (002) exchange-biased IrMn/CoFe bilayers

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Exchange bias in epitaxial Fe/Ir_0.2Mn_0.8bilayers grown on MgO (0 0 1)

Exchange bias in epitaxial Fe/Ir_0.2Mn_0.8bilayers grown on MgO (0 0 1)