Abstract
With the help of electron beam evaporation of mechanical mixtures of nonmagnetic micron powders ZnO and carbon in vacuum with the subsequent annealing of evaporation products in air at the temperature of 773 K, single-phase crystal nanopowders ZnO-C were produced with the hexagonal wurtzite structure and low content of the carbon dopant not exceeding 0.25 wt%. It was established that doping ZnO with carbon stimulates primary growth of nanoparticles along the direction 0001 in the coatings. Nanocrystal growth in coatings occurs in the same way as crystal growth in thin films, with growth anisotropy in the c-axis direction in wurtzite ZnO. Element mapping has confirmed homogeneous distribution of carbon in ZnO lattice. Ferromagnetism of single-phase crystal nanopowders ZnO-C with the hexagonal wurtzite structure and low content of the carbon dopant not exceeding 0.25 wt% was produced at room temperature. Ferromagnetic response of the doped NP ZnO-C has exceeded the ferromagnetic response of pure NP ZnO 5 times. The anhysteretic form of magnetization curves NP ZnO-C indicates aspiration of samples to superparamagnetism manifestation.
Highlights
The diluted magnetic semiconductors (DMS) cause huge interest due to their potential use in devices of spintronics [1, 2]
Occurrence of ferromagnetism at the room temperature (RTFM) in ZnO is connected to the presence of oxygen vacancies (VO) [4, 5], vacancies of Zn (VZn) [6, 7], and interstitial atoms Zn (Zni) [8]
All peaks on diffraction patterns correspond to hexagonal wurtzite structure of ZnO with the space group P63mc (Joint Committee on Powder Diffraction Standards (JCPDS) the card number 36-1451)
Summary
The diluted magnetic semiconductors (DMS) cause huge interest due to their potential use in devices of spintronics [1, 2]. Occurrence of ferromagnetism at the room temperature (RTFM) in ZnO is connected to the presence of oxygen vacancies (VO) [4, 5], vacancies of Zn (VZn) [6, 7], and interstitial atoms Zn (Zni) [8]. It is theoretically shown [9, 10] that VZn has the magnetic moment. Detailed theoretical research of the vacancy-induced magnetism in ZnO thin films has shown [12, 13] that RTFM of films occurs due to VZn, but not due to VO
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