Paramagnetism in Mn/Fe implanted ZnO

Gunnlaugsson, H. P.; Mølholt, T. E.; Mantovan, R.; Masenda, H.; Naidoo, D.; Dlamini, W. B.; Sielemann, R.; Bharuth-Ram, K.; Weyer, G.; Johnston, K.; Langouche, Guido; Ólafsson, S.; Gíslason, H. P.; Kobayashi, Yoshihiko; Yoshida, Yutaka; Fanciulli, M.

doi:10.1063/1.3490708

Cited by 45 publications

(57 citation statements)

References 20 publications

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“…Indeed, while several DMS/DMO have been predicted to have a Curie temperature (T c ) above room temperature, no experimental report of T c > 300K has been left unchallenged by other studies [15]. Moreover some results suggest that magnetic impurities act as paramagnetic (PM) centers with unusually long relaxation time [16], at least at very low doping concentrations.…”

Section: Introductionmentioning

confidence: 99%

Exploiting magnetic properties of Fe doping in zirconia

Sangalli¹,

Cianci²,

Lamperti³

et al. 2013

Eur. Phys. J. B

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Abstract. In this study we explore, both from theoretical and experimental side, the effect of F e doping in ZrO2 (ZrO2:F e). By means of first principles simulation we study the magnetization density and the magnetic interaction between F e atoms. We also consider how this is affected by the presence of oxygen vacancies and compare our findings with models based on impurity band [1] and carrier mediated magnetic interaction [2]. Experimentally thin films (≈ 20nm) of ZrO2:F e at high doping concentration are grown by atomic layer deposition. We provide experimental evidence that F e is uniformly distributed in the ZrO2 by transmission electron microscopy and energy dispersive X-ray mapping, while X-ray diffraction evidences the presence of the fluorite crystal structure. Alternating gradient force magnetometer measurements show magnetic signal at room temperature, however with low magnetic moment per atom. Results from experimental measures and theoretical simulations are compared.

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Section: Introductionmentioning

confidence: 99%

Exploiting magnetic properties of Fe doping in zirconia

Sangalli¹,

Cianci²,

Lamperti³

et al. 2013

Eur. Phys. J. B

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“…While it was not possible to determine from the measured data in Ref. [20] whether ferromagnetism or paramagnetism was responsible for the magnetic sextet seen, this was recently achieved by the same group by means of measuring the angular dependence of the Mössbauer spectra in an external magnetic field [23]. According to these new data the coupling is clearly paramagnetic and ferromagnetism could be ruled out, .thus obviously reducing the perspectives for ZnO:Fe to act as a true dilute magnetic semiconductor.…”

Section: Mössbauer Effectmentioning

confidence: 98%

“…In comparison to 57* Fe Mössbauer studies which use long-lived 57 Co (271 d) sources, both in absorption and emission mode, the short half life of 57 Mn in combination with the high beam intensity available at ISOLDE (up to 4×10 8 atoms/s corresponding to ~60 pA) allow for several orders of magnitude faster data taking, making it possible to record hundreds of Mössbauer spectra per day, which is not possible in any other radioactive ion beam facility. Since then, 57 Mn→ 57 Fe Mössbauer experiments have been undertaken in a large variety of semiconductors and oxides during the last couple of years, with a focus on Si, Si x Ge 1−x [18], diamond [19] and especially ZnO [20][21][22][23] but also in some geological sampes [24].…”

Section: Mössbauer Effectmentioning

confidence: 99%

Materials science and biophysics applications at the ISOLDE radioactive ion beam facility

Wahl

2011

Nuclear Instruments and Methods in Physics Research Section B:

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The ISOLDE isotope separator facility at CERN provides a variety of radioactive ion beams, currently more than 800 different isotopes from ~65 chemical elements. The radioisotopes are produced on-line by nuclear reactions from a 1.4 GeV proton beam with various types of targets, outdiffusion of the reaction products and, if possible, chemically selective ionisation, followed by 60 kV acceleration and mass separation. While ISOLDE is mainly used for nuclear and atomic physics studies, applications in materials science and biophysics account for a significant part (currently ~15%) of the delivered beam time, requested by 18 different experiments. The ISOLDE materials science and biophysics community currently consists of ~80 scientists from more than 40 participating institutes and 21 countries. In the field of materials science, investigations focus on the study of semiconductors and oxides, with the recent additions of nanoparticles and metals, while the biophysics studies address the toxicity of metal ions in biological systems. The characterisation methods used are typical radioactive probe techniques such as Mössbauer spectroscopy, perturbed angular correlation, emission channeling, and tracer diffusion studies. In addition to these "classic" methods of nuclear solid state physics, also standard semiconductor analysis techniques such as photoluminescence or deep level transient spectroscopy profit from the application of radioactive isotopes, which helps them to overcome their chemical "blindness" since the nuclear half life of radioisotopes provides a signal that changes in time with characteristic exponential decay or saturation curves. In this presentation an overview will be given on the recent research activities in materials science and biophysics at ISOLDE, presenting some of the highlights during the last five years, together with a short outlook on the new developments under way.

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“…However, from these data alone, it was not possible to determine whether ferromagnetism or paramagnetism was responsible for the observed magnetic sextet [100]. The same group has recently shown, by means of measuring the angular dependence of the Mössbauer spectra in an external magnetic field, that the coupling is clearly paramagnetic and ferromagnetism could be ruled out [103], which obviously reduces the perspectives for ZnO:Fe acting as a true dilute magnetic semiconductor. The interface between nuclear and solid state physics has always been a fertile ground for discovering new phenomena and attractive applications.…”

Section: F(ω)mentioning

confidence: 99%