Ferromagnetism above room temperature in bulk and transparent thin films of Mn-doped ZnO

Sharma, Parmanand; Gupta, Amita; Rao, K. V.; Owens, Frank J.; Sharma, Renu; Ahuja, Rajeev; Osório-Guillén, J. M.; Johansson, Börje; Gehring, G. A.

doi:10.1038/nmat984

Cited by 1,755 publications

(1,110 citation statements)

References 23 publications

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“…The main challenge for this kind of materials is to present a Curie Temperature (TC) above 300 K in order to be useful for technological applications. Despite some initial promising results on Mn:ZnO [3], it is not clear if DMS can exhibit this required high temperature magnetism. For most of the experimental results doubts arose about the real origin of magnetism [4,5,6].…”

Section: /11mentioning

confidence: 99%

Magnetic Properties of ZnO Nanoparticles

et al. 2007

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In this work it is experimentally shown that capping ZnO nanoparticles with organic molecules leads to the appearance of magnetism at room temperature.The bonds between the molecules and the Zn atoms at the nanoparticle surface alter its electronic structure (as XANES and photoluminescence spectra demonstrate) arising magnetic moments with values that depend on the nature of the molecule. This result points out the possibility to observe magnetism at nanoscale in semiconductors without typical magnetic atoms (transition metals and rare earths).

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Section: /11mentioning

confidence: 99%

Magnetic Properties of ZnO Nanoparticles

et al. 2007

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“…Both the existence and absence of FM have been reported in Mn-doped ZnO thin fi lms. Spin-glass behavior [4], paramagnetism [5], FM with a T C of 45 K [6], and room-temperature FM [7] have been observed. This suggests a strong dependence of magnetic properties on the sample-preparation conditions [8].…”

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confidence: 93%

Structure and magnetic properties of Mn-doped ZnO thin films

Zhang¹,

Li²,

Shi³

et al. 2007

J. Phys.: Condens. Matter

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We report the structure and magnetic properties of Zn1−xMnxO thin films grown on Si(001) substrates by pulsed laser deposition. Structure and phase evolution with Mn doping has been studied using x-ray diffraction, electron diffraction, and high-resolution electron microscopy. The undoped and 1% Mn-doped ZnO films are completely (001) oriented, and further Mn doping deteriorates the (001) orientation. For Mn concentrations below 3%, only the hexagonal ZnO phase exists in the films without secondary phases. As the Mn concentration reaches 5%, secondary phase Mn2O3 was found aggregating at grain boundaries. All the Mn-doped films show ferromagnetic properties at room temperature, and the magnetic moment decreases as the Mn concentration increases. Our results suggest that the ferromagnetism observed in Zn1−xMnxO thin films is intrinsic rather than associated with secondary phases.

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“…The now‐observed NIR emission clearly cannot be attributed to the typically isolated Mn 2+ ions; however, one possible explanation is given by the occurrence of Mn 2+ ion aggregation. Interionic coupling between transition metal ions often leads to fascinating physical phenomena, such as ferromagnetism in Zn 1– x Mn x Te15 and ZnO:Mn,16 multiferroism in BiFeO 3 thin films,17 superconduction in Y/La–Ba/Sr–Cu–O ceramics,18, 19 and giant magnetoresistance in thin films of La 2/3 Ba 1/3 MnO x 20 and La 0.67 Ca 0.33 MnO x 21. These physical properties are primarily ascribed to the delocalization and interaction of the 3d electrons of transition metal ions.…”

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confidence: 99%

Tailored Near‐Infrared Photoemission in Fluoride Perovskites through Activator Aggregation and Super‐Exchange between Divalent Manganese Ions

et al. 2015

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Biomedical imaging and labeling through luminescence microscopy requires materials that are active in the near‐infrared spectral range, i.e., within the transparency window of biological tissue. For this purpose, tailoring of Mn2+–Mn2+ activator aggregation is demonstrated within the ABF3 fluoride perovskites. Such tailoring promotes distinct near‐infrared photoluminescence through antiferromagnetic super‐exchange across effective dimers. The crossover dopant concentrations for the occurrence of Mn2+ interaction within the first and second coordination shells comply well with experimental observations of concentration quenching of photoluminescence from isolated Mn2+ and from Mn2+–Mn2+ effective dimers, respectively. Tailoring of this procedure is achieved via adjusting the Mn–F–Mn angle and the Mn–F distance through substitution of the A+ and/or the B2+ species in the ABF3 compound. Computational simulation and X‐ray absorption spectroscopy are employed to confirm this. The principle is applied to produce pure anti‐Stokes near‐infrared emission within the spectral range of ≈760–830 nm from codoped ABF3:Yb3+,Mn2+ upon excitation with a 976 nm laser diode, challenging the classical viewpoint where Mn2+ is used only for visible photoluminescence: in the present case, intense and tunable near‐infrared emission is generated. This approach is highly promising for future applications in biomedical imaging and labeling.

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Ferromagnetism above room temperature in bulk and transparent thin films of Mn-doped ZnO

Cited by 1,755 publications

References 23 publications

Magnetic Properties of ZnO Nanoparticles

Magnetic Properties of ZnO Nanoparticles

Structure and magnetic properties of Mn-doped ZnO thin films

Tailored Near‐Infrared Photoemission in Fluoride Perovskites through Activator Aggregation and Super‐Exchange between Divalent Manganese Ions

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