Identifying local dopant structures and their impact on the magnetic properties of spintronic materials

Green, R. J.; Chang, Gap Soo; Zhang, X. Y.; Dinia, A.; Kurmaev, E.Z.; Moewes, A.

doi:10.1103/physrevb.83.115207

Cited by 14 publications

(11 citation statements)

References 30 publications

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“…This can be interpreted as originating from pairs of Mn 4+ ions ferromagnetically coupled with a paramagnetic behavior at all temperatures. The FM and PM coefficients from the fits are FM = 250 emu/cm 3 and PM = 542 emu/cm 3 for sample A-MnO 2Àδ /ZnO and FM = 200 emu/ cm 3 and PM = 483 emu/cm 3 for B-MnO 2Àδ /ZnO, with an estimated error of (10 emu/cm 3 in all cases. That means that, in both samples, approximately 1/3 of the magnetization is related to a room temperature ferromagnetic phase while the other, about 2/3, corresponds to the paramagnetic fraction.…”

Section: Mðh T Jþmentioning

confidence: 90%

“…For Mn–Zn–O, intrinsic low-temperature ferromagnetism has been assigned to low dopant concentrations of Mn substituting into the host lattice . However, different types of defects, such as oxygen and zinc vacancies and hydrogen or zinc interstitials, have been proposed to induce RTFM in ZnO-based systems, either doped or pristine. − Short-range ferromagnetic spin–spin interaction mediated by coupling of hydrogen shallow donors and Mn ions has also been reported in 8 at.…”

Section: Introductionmentioning

confidence: 99%

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On the Origin of the Magnetism of Mn–Zn–O Systems: Structural, Electronic, and Magnetic Study of Exotic MnO_2−δ/ZnO Thin Films

et al. 2011

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The structural, electronic, and magnetic characterization of sputtered MnO2−δ/ZnO films showing room temperature ferromagnetism has been carried out by a number of techniques. To elucidate the origin of the ferromagnetic order, a novel approach by studying XAS and XMCD signals at both Mn and Zn K edges in combination with the macroscopic magnetization measurements has been performed. The analysis of the XAS profile at the Mn edge indicates the coexistence of Mn4+/Mn3+ with a slightly distorted MnO2−δ environment. The XMCD signal at the Zn K edge indicates the existence of an intrinsic magnetic moment in Zn. The Zn edge dichroic intensity is, however, 1 order of magnitude lower than in the case of Mn, being the magnetic moment of Mn, 2.1–2.4 μB per Mn cation participating in the ferromagnetic phase, the main contribution to the total magnetization. The ferromagnetic phase has been assigned to high-density regions of Mn cations with a MnO2−δ distorted environment, mainly allocated at the nonstoichiometric and highly defective ZnO grain boundaries, with a sufficient extension to overcome the thermal energy over room temperature. The ferromagnetic coupling has been related to modifications of the Mn–O–Mn bonds, distances, and angles, promoted by neighboring ZnO and forming stable magnetic configurations that lead to new forms of exchange interaction: ferromagnetic superexchange or a double-exchange mechanism between the Mn4+ and Mn3+. Highly defective regions and structural distortions, together with complex Mn oxidation states, appear to be key features in the magnetic properties of Mn–Zn–O.

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Section: Mðh T Jþmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

On the Origin of the Magnetism of Mn–Zn–O Systems: Structural, Electronic, and Magnetic Study of Exotic MnO_2−δ/ZnO Thin Films

et al. 2011

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“…The p-type conductivity and enhanced RTFM are assigned to the formation of a defect complex (N O -Li I ). Green et al 56 have employed resonant inelastic X-ray scattering to study dopant-host interactions and their effects on the magnetic properties of two DMS systems, namely Mn:ZnO and Co:CeO 2 . In the case of Mn:ZnO, low dopant concentrations lead to low temperature ferromagnetism while excess dopant concentration is seen to give an antiferromagnetic phase because of the presence of the secondary phase MnO.…”

Section: Magnetism In Metal Oxides With Dilute Doping Of Transition E...mentioning

confidence: 99%

Ferromagnetism in metal oxide systems: interfaces, dopants, and defects

2013

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Ferromagnetism in metal oxide systems has always attracted scientific attention in view of the intriguing and interesting interplay of spin, charge, orbital and lattice degrees of freedom that such systems display.This trend appears to be continuing with enhanced focus on interface systems, multiferroics, diluted magnetic semiconducting oxides (DMSOs) and nanomaterial magnetism. Newer techniques are being applied to bring out materials issues that are critical to the precise understanding of the origin of magnetism in certain cases. Interest is also beginning to grow in exploring application potential of some such systems. In this article we review the developments in this field by late 2011 and 2012.

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“…The crystal field multiplet calculations in this work use the algorithm initially formulated by Cowan, and the working code subsequently expanded on by Haverkort and Green et al [22][23][24][25] The free parameters include the crystal field strength (from which the local symmetry [27] and the difference between left and right polarized absorption spectra determines the orbital and spin magnetic moments per Fe atom. [28] can be deduced), oxidation state, and the scaling of the intra-atomic Coulomb and exchange (Slater) integrals.…”

Section: Experiments and Calculation Detailsmentioning

confidence: 99%

Section: Experiments and Calculation Detailsmentioning

confidence: 99%

Tunability of room-temperature ferromagnetism in spintronic semiconductors through nonmagnetic atoms

et al. 2017

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The implementation and control of room temperature ferromagnetism (RTFM) by adding magnetic atoms to a semiconductor's lattice has been one of the most important problems in solid state state physics in the last decade. Herein we report for the first time, to our knowledge, on the mechanism that allows RTFM to be tuned by the inclusion of non-magnetic aluminum in nickel ferrite. This material, NiFe2−xAlxO4 (x=0, 0.5, 1.5), has already shown much promise for magnetic semiconductor technologies, and we are able to add to its versatility technological viability with our results. The site occupancies and valencies of Fe atoms (Fe 3+ T d , Fe 2+ O h , and Fe 3+ O h ) can be methodically controlled by including aluminum. Using the fact that aluminum strongly prefers a 3+ octahedral environment, we can selectively fill iron sites with aluminum atoms, and hence specifically tune the magnetic contributions for each of the iron sites, and therefore the bulk material as well. Interestingly, the influence of the aluminum is weak on the electronic structure (supplemental material), allowing one to retain the desirable electronic properties while achieving desirable magnetic properties.

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Identifying local dopant structures and their impact on the magnetic properties of spintronic materials

Cited by 14 publications

References 30 publications

On the Origin of the Magnetism of Mn–Zn–O Systems: Structural, Electronic, and Magnetic Study of Exotic MnO_2−δ/ZnO Thin Films

On the Origin of the Magnetism of Mn–Zn–O Systems: Structural, Electronic, and Magnetic Study of Exotic MnO_2−δ/ZnO Thin Films

Ferromagnetism in metal oxide systems: interfaces, dopants, and defects

Tunability of room-temperature ferromagnetism in spintronic semiconductors through nonmagnetic atoms

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Identifying local dopant structures and their impact on the magnetic properties of spintronic materials

Cited by 14 publications

References 30 publications

On the Origin of the Magnetism of Mn–Zn–O Systems: Structural, Electronic, and Magnetic Study of Exotic MnO2−δ/ZnO Thin Films

On the Origin of the Magnetism of Mn–Zn–O Systems: Structural, Electronic, and Magnetic Study of Exotic MnO2−δ/ZnO Thin Films

Ferromagnetism in metal oxide systems: interfaces, dopants, and defects

Tunability of room-temperature ferromagnetism in spintronic semiconductors through nonmagnetic atoms

Contact Info

Product

Resources

About

On the Origin of the Magnetism of Mn–Zn–O Systems: Structural, Electronic, and Magnetic Study of Exotic MnO_2−δ/ZnO Thin Films

On the Origin of the Magnetism of Mn–Zn–O Systems: Structural, Electronic, and Magnetic Study of Exotic MnO_2−δ/ZnO Thin Films