Observation of optical properties related to room-temperature ferromagnetism in co-sputtered Zn1−Co O thin films

Magnetic oxide semiconductors, oxide semiconductors doped with transition metal elements, are one of the candidates for a high Curie temperature ferromagnetic semiconductor that is important to realize semiconductor spintronics at room temperature. We review in this paper recent progress of researches on various magnetic oxide semiconductors. The magnetization, magneto-optical effect, and magneto-transport such as anomalous Hall effect are examined from viewpoint of feasibility to evaluate the ferromagnetism. The ferromagnetism of Co-doped TiO 2 and transition metal-doped ZnO is discussed.

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“…>250K [52] 225-300K [53 ] 250K with Sn [87] -225-300K [53] >350K [56] >r.t. [66,69] >350K with Li [90] --10 (17)…”

Section: Kmentioning

confidence: 99%

Magnetic oxide semiconductors

Fukumura

Toyosaki

Yamada

2005

Semicond. Sci. Technol.

216

107

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“…The origin of the ferromagnetism was not "intrinsic" however, but resulted from the formation of cobalt microclusters. Finally, Lim et al [11] reported ferromagnetism in Zn 1−x Co x O (0.02 ≤x≤ 0.40) films grown by magnetron co-sputtering on sapphire. Other evidence for magnetic phenomena include observation of a large magnetic circular dichroism signal at an energy corresponding to the ZnO band edge in thin films of ZnO doped with Mn, Co, Ni and Cu [6,7].…”

Section: Introductionmentioning

confidence: 98%

Search for ferromagnetism in transition-metal-doped piezoelectric ZnO

2004

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We present the results of a computational study of ZnO in the presence of Co and Mn substitutional impurities. The goal of our work is to identify potential ferromagnetic ground states within the (Zn,Co)O or (Zn,Mn)O material systems that are also good candidates for piezoelectricity. We find that, in contrast to previous results, robust ferromagnetism is not obtained by substitution of Co or Mn on the Zn site, unless additional carriers (holes) are also incorporated. We propose a practical scheme for achieving such p-type doping in ZnO.

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“…In spite of numerous studies the ferromagnetic properties of transition metal cations doped wurtzite ZnO host is still a controversial issue [1][2][3][4][5][6]. A high temperature ferromagnetism was reported numerously for Co doped ZnO in thin films produced by all accessible methods including pulsed layer deposition [7], the magnetron co-sputtering [8], the solgel method [9], and epitaxial thin films [10]. Recently, Fe doped ZnO nanostructures, synthesized by the sol-gel method, were observed to be ferromagnetic [11].…”

Section: Introductionmentioning

confidence: 99%

Magnetic Fe doped ZnO nanofibers obtained by electrospinning

Baranowska‐Korczyc

Reszka

Sobczak

et al. 2011

J Sol-Gel Sci Technol

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We demonstrate structural and room temperature magnetic properties of Fe doped ZnO nanofibers (NFs) obtained by electrospinning followed by calcination. The observed NFs, formed from crystalographically oriented, approximately 4.5 nm particles conglomerates, were approximately 200 nm in diameter. The reported synthesis of room temperature ferromagnetic Fe doped ZnO NFs is both facile and economical, and is therefore suggested as a generic method of fabricating biocompatible magnetic materials. The major substrates selected for the NFs synthesis (Zn, Fe) comprised of relatively low toxicity materials. Incorporating 10% Fe into ZnO does not modify the wurtzite crystal structure of the host material. No evidence of impurity phase was detected by either X-ray or electron diffraction. Magnetometry studies and Magnetic Force Microscopy imaging reveal a local ferromagnetic order that persists up to room temperature. We suggest that the observed phenomenon is either due to a mechanism mediated by presence of oxygen vacancies and/or is related to iron-rich precipitates.

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Observation of optical properties related to room-temperature ferromagnetism in co-sputtered Zn1−Co O thin films

Cited by 105 publications

References 18 publications

Magnetic oxide semiconductors

Magnetic oxide semiconductors

Search for ferromagnetism in transition-metal-doped piezoelectric ZnO

Magnetic Fe doped ZnO nanofibers obtained by electrospinning

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