Ion induced modifications of Mn-doped ZnO films

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Vol. 365; pp. 191 - 195
• Main Authors: Matsunami, N., Itoh, M., Kato, M., Okayasu, S., Sataka, M., Kakiuchida, H.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-12-2015
• Subjects: Curie temperature; Electrical resistivity; Fluence; Ion impact; Irradiation; Manganese; Mn-doped ZnO; Modifications of atomic- and electronic-structures and magnetism; Resistivity; X-ray diffraction; Zinc oxide; Mn-doped ZnO; Modifications of atomic- and electronic-structures and magnetism; Resistivity
• ISSN: 0168-583X; 1872-9584
• DOI: 10.1016/j.nimb.2015.08.010

We have studied ion impact effects on atomic structure in terms of X-ray diffraction (XRD), optical absorption and electrical resistivity of Mn(6%)-doped ZnO films under 100MeV Xe ion impact at room temperature. We find the monotonic reduction of the XRD intensity to 1/50 of that of unirradiated film at 5×1014cm−2 and the lattice compaction of 0.6% for the ion fluence >1013cm−2, little bandgap change (<0.02eV) and decrease of the resistivity by 4 order of magnitude. The resistivity modification has been compared with that by irradiations of low energy ions such as 100keV Ne and N, which show more effective decrease of resistivity. We also find that temperature (T) dependence of the magnetic susceptibility (χ) of Mn-doped ZnO follows the Curie law: χ=χo+C/T (i.e., paramagnetic) and the Curie constant C decreases to a half of that before irradiation (CO=0.012emucm−3K) at 100MeV Xe ion fluence of 1012cm−2. Relationship is discussed between modifications of the magnetic property and change in the valence of Mn, using a simple and crude argument.