Inelastic neutron scattering studies of II-VI diluted magnetic semiconductors (invited)

Giebułtowicz, T. M.; Rhyne, J. J.; Furdyna, J. K.; Klosowski, P.

doi:10.1063/1.344683

Cited by 61 publications

(28 citation statements)

References 26 publications

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“…3 and 4 can be further tested by applying hydrostatic pressure to tune the exchange coupling J pd . Earlier investigations on various magnetic semiconductors [6,17] In the FM phase magnetic scattering varies as the product of J pd and P, which itself varies as the strength of the J pd coupling. Taking both effects into account, Eq.…”

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confidence: 99%

Magnetic Scattering of Spin Polarized Carriers in(In,Mn)SbDilute Magnetic Semiconductor

et al. 2005

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Magnetoresistance measurements on the magnetic semiconductor (In,Mn)Sb suggest that magnetic scattering in this material is dominated by isolated Mn 2+ ions located outside the ferromagnetically-ordered regions when the system is below Tc. A model is proposed, based on the p-d exchange between spin-polarized charge carriers and localized Mn 2+ ions, which accounts for the observed behavior both below and above the ferromagnetic phase transition. The suggested picture is further verified by high-pressure experiments, in which the degree of magnetic interaction can be varied in a controlled way.PACS numbers: 72.25. Dc, 75.30Et, 75.47.De, 75.50.Pp The presence of charge and spin degrees of freedom in III-Mn-V magnetic semiconductors alloys opens new perspectives for spintronic applications [1,2,3]. In these systems the Mn 2+ ions provide S=5/2 magnetic moments, and also act as a source of valence band holes that mediate Mn 2+ -Mn 2+ interactions. The interactions between the randomly positioned magnetic ions are predominantly ferromagnetic (FM), resulting in a low temperature FM phase [4,5,6,7,8,9]. Thus the magnetic and the electrical transport properties of III-Mn-V materials are fundamentally inter-dependent. Although many aspects of free carrier magnetotransport have already been explored in these materials, its microscopic understanding is still far from complete. Recent scaling theory on Anderson-localized disordered ferromagnets applies to transport in the localized limit [10], but the more interesting "metallic" systems -where the mean free path satisfies the k F l >> 1 condition (where k F is the Fermi wave number) -require a different approach.Many spintronic applications envision spin injection and/or spin-polarized current, and are thus expected to hinge critically on our understanding of spin scattering of the charge carriers. In this paper we present a detailed experimental study of magnetic scattering processes in the dilute magnetic semiconductor (In,Mn)Sb. We find that in the FM phase the positional disorder of the magnetic moments is reflected in the slowly saturating nature of both the magnetization and magnetoresistance. This suggests the presence of isolated Mn 2+ ions located outside the FM-ordered regions. The large negative magnetoresistance observed below T c is attributed to a first order magnetic scattering of spin-polarized holes on such isolated paramagnetic Mn 2+ ions. Above T c the spontaneous spin polarization of the carriers is lost and second-order spin-independent processes begin to dominate. This picture is supported by high pressure measurements, in which the interaction between charge-carrying holes and localized Mn 2+ ions can be experimentally varied [11].In the present work we present results obtained on In 1−x Mn x Sb for x = 0.02. Similar behavior has been found for other concentrations. More importantly the same qualitative behavior has also been reported for the most widely studied magnetic semiconductor Ga 1−x Mn x As [4,12]. We therefore believe that the results on ...

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Magnetic Scattering of Spin Polarized Carriers in(In,Mn)SbDilute Magnetic Semiconductor

et al. 2005

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“…Magnetization steps x = 0.031 J 1 = −8.79 ± 0.14 [17] Inelastic neutron scattering x = 0.02 J 1 = −9.45 ± 0.17 [15] Inelastic neutron scattering x = 0.05 J 1 = −9.57 ± 0.17 x = 0.02 J 1 = −9.35 ± 0.05 [18] Inelastic neutron scattering 0.01 ≤ x ≤ 0.03 J 1 = −9.332 ± 0.029 [19] Inelastic neutron scattering [20] Raman scattering x = 0.023 J * 1 = −11.0 ± 0.2 [21] Magnetization steps [22] Magnetization steps…”

Section: Compoundmentioning

confidence: 99%

Are values of parameters describing magnetic properties of crystal really fixed?

Szuszkiewicz

Dynowska

2005

Journal of Alloys and Compounds

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“…For these materials a typical value of J1/kB is -10 K. Such a value implies that the first J1 step occurs typically near 15 T (150 kG). For Cobased II-VI DMS the values of J1 are much higher [10], so that very high fields are required to observe the J1 steps. Only recently was the first J1 step observed in CdCoS and in CdCoSe using 60 T pulsed fields [11].…”

Section: The J1 Modelmentioning

confidence: 99%

“…The leading techniques for measuring the largest exchange constant, J 1, use either high-field magnetization steps (MSTs) [3,9] or inelastic neutron scattering [10]. The first generation of MSTs succeeded in determining J1 in virtually all Mn-based II-VI DMS.…”

Section: Magnetization Stepsmentioning

confidence: 99%

Diluted Magnetic Semiconductors in High Magnetic Fields

Shapira

1995

Acta Phys. Pol. A

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Magnetization studies of diluted magnetic semiconductors in high fields are reviewed. Magnetization steps due to pairs were originally used to measure the near neighbor exchange constant J1. They are now also used to determine: (1) the smaller exchange constants J2 and J3 , (2) the difference between J1 's for inequivalent near neighbors in wurtzite diluted magnetic semiconductors, and (3) the Dzyaloshinski-Moriya interaction. A different type of magnetization step, due to isolated ions, is used to determine the un iaxial anisotropy of Co ++ ions in wurtzite diluted magnetic semiconductors. In Fe-based diluted magnetic semiconductors the high-field magnetization exhibits two effects: (1) strong dependence on field direction in cubic diluted magnetic semiconductors, and (2) reversal of the un iaxíal magnetization-anisotropy in wurtzite diluted magnetic semiconductors.In (100) EuTe/PbTe superlattices the antiferromagnetic transition, both at zero and finite H, is depressed when the EuTe 1ayer becomes only a few monolayers thick. The easy directions are in the (100) płane of the layer, which is explained by the dipole-dipole anisotropy.

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Inelastic neutron scattering studies of II-VI diluted magnetic semiconductors (invited)

Cited by 61 publications

References 26 publications

Magnetic Scattering of Spin Polarized Carriers in(In,Mn)SbDilute Magnetic Semiconductor

Magnetic Scattering of Spin Polarized Carriers in(In,Mn)SbDilute Magnetic Semiconductor

Are values of parameters describing magnetic properties of crystal really fixed?

Diluted Magnetic Semiconductors in High Magnetic Fields

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