An X- and Q-Band Fe³⁺ EPR Study of Nanoparticles of Magnetic Semiconductor Zn_1−xFe_xO

Authors

Sushil K. Misra, Concordia University
S. I. Andronenko, Kazan Federal University
A. Thurber, Boise State University
A. Punnoose, Boise State UniversityFollow
A. Nalepa, Max-Planck-Institut für Chemische Energie Konversion

Document Type

Article

Publication Date

8-2014

Abstract

EPR studies on two types of nanoparticles of Fe³⁺ doped, 0.1–10%, ZnO, NL and QJ, prepared using similar chemical hydrolysis methods, in diethylene glycol, and in denatured ethanol solutions, respectively, were carried out at X-band (~9.5 GHz) at 77 K and at Q-band (~34.0 GHz) at 10, 80, and 295 K. To interpret the experimental results, EPR spectra were simulated by exact diagonalization of the spin-Hamiltonian matrix to identify the Fe ions at different magnetically active sites in these samples. The simulation for NL samples revealed that they contained (i) Fe³⁺ ions, which substituted for Zn ions, the zero-field splitting (ZFS) parameter which has a large distribution over the sample due to oxygen vacancies in the second coordination sphere; (ii) EPR signal from surface oxygen defects; and (iii) ferromagnetically (FM) coupled Fe ions with concentration of Fe more than 1%. The EPR spectra for QJ samples are very different from those for NL samples, exhibiting only rather intense FM EPR lines. The FM and EPR spectra in NL and/or QJ samples are found to vary strongly with differences in the surface morphology of nanoparticles.

Publication Information

Misra, Sushil K.; Andronenko, S. I.; Thurber, A.; Punnoose, A.; and Nalepa, A.. (2014). "An X- and Q-Band Fe³⁺ EPR Study of Nanoparticles of Magnetic Semiconductor Zn_1−xFe_xO". Journal of Magnetism and Magnetic Materials, 36382-87. http://dx.doi.org/10.1016/j.jmmm.2014.03.031