Giant magnetic moments in ferromagnetic oxide semiconductors

Orlov, A. F.; Перов, Н. С.; Balagurov, L. A.; Konstantinova, A.S.; Yarkin, D. G.

doi:10.1134/s002136400717016x

Cited by 7 publications

(4 citation statements)

References 9 publications

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“…The most interesting question is why do we obtain such large S values. We would like to point out here that this large value of S has also been observed by others in the DMS systems 29,30,31,32 . One possible way for formation of large moments is by clustering of Mn atoms.…”

Section: Resultssupporting

confidence: 86%

Change in the room temperature magnetic property of ZnO upon Mn doping

Banerjee

Rajendran²,

Gayathri

et al. 2008

Journal of Applied Physics

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We present in this paper the changes in the room temperature magnetic property of ZnO on Mn doping prepared using solvo-thermal process. The zero field cooled (ZFC) and field cooled (FC) magnetisation of undoped ZnO showed bifurcation and magnetic hysteresis at room temperature. Upon Mn doping the magnetic hysteresis at room temperature and the bifurcation in ZFC-FC magnetization vanishes. The results seem to indicate that undoped ZnO is ferromagnetic while on the other hand the Mn doped ZnO is not a ferromagnetic system. We observe that on addition of Mn atoms the system shows antiferromagnetism with very giant magnetic moments.Comment: 5 figure

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Section: Resultssupporting

confidence: 86%

Change in the room temperature magnetic property of ZnO upon Mn doping

Banerjee

Rajendran²,

Gayathri

et al. 2008

Journal of Applied Physics

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“…75 Thus the contribution of spin-orbit coupling interaction should not be dominant. As for a lattice polarization mechanism, 76 an inverse ferromagnetism dependence on dopant concentration can substantially meet our case. We have known that, if the doping concentration is 0.2%, the average distance between Cu ions in ZnO is about 35 nm.…”

Section: Amine Activation and Pl Evolutionsupporting

confidence: 68%

Acceptor defect-participating magnetic exchange in ZnO : Cu nanocrystalline film: defect structure evolution, Cu–N synergetic role and magnetic control

Zhu

et al. 2015

J. Mater. Chem. C

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“…We really should not be seeing uniform ferromagnetism at temperatures of many hundreds of degrees in these materials. Another problem is that the observed magnetization sometimes exceeds the maximum value that can be associated with ferromagnetically-aligned dopant ions [15,22,23]. The Ferromagnetic d 0 systems [4]- [6], [24]- [29], where there are no magnetic dopants, are the most extreme examples.…”

Section: Introductionmentioning

confidence: 99%

Ferromagnetism in defect-ridden oxides and related materials

Coey¹,

et al. 2010

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The existence of high-temperature ferromagnetism in thin films and nanoparticles of oxides containing small quantities of magnetic dopants remains controversial. Some regard these materials as dilute magnetic semiconductors, while others think they are ferromagnetic only because the magnetic dopants form secondary ferromagnetic impurity phases such as cobalt metal or magnetite. There are also reports in d 0 systems and other defective oxides that contain no magnetic ions. Here, we investigate TiO 2 (rutile) containing 1 -5% of iron cations and find that the roomtemperature ferromagnetism of films prepared by pulsed-laser deposition is not due to magnetic ordering of the iron. The films are neither dilute magnetic semiconductors nor hosts to an iron-based ferromagnetic impurity phase. A new model is developed for defect-related ferromagnetism which involves a spin-split defect band populated by charge transfer from a proximate charge reservoir -in the present case a mixture Fe 2+ and Fe 3+ ions in the oxide lattice. The phase diagram for the model shows how inhomogeneous Stoner ferromagnetism depends on the total number of electrons N tot , the Stoner exchange integral I and the defect bandwidth W; the band occupancy is governed by the d-d Coulomb interaction U. There are regions of ferromagnetic metal, half-metal and insulator as well as nonmagnetic metal and insulator. A characteristic feature of the high-temperature Stoner magnetism is an an anhysteretic magnetization curve which is practically temperature independent below room temperature. This is related to a wandering ferromagnetic axis which is determined by local dipole fields. The magnetization is limited by the defect concentration, not by the 3d doping. Only 1-2 % of the volume of the films is magnetically ordered.

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Giant magnetic moments in ferromagnetic oxide semiconductors

Cited by 7 publications

References 9 publications

Change in the room temperature magnetic property of ZnO upon Mn doping

Change in the room temperature magnetic property of ZnO upon Mn doping

Acceptor defect-participating magnetic exchange in ZnO : Cu nanocrystalline film: defect structure evolution, Cu–N synergetic role and magnetic control

Ferromagnetism in defect-ridden oxides and related materials

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