Room temperature d0 ferromagnetism, band-gap reduction, and high optical transparency in p-type K-doped ZnO compounds for spintronics applications.

The present work emphases on the structural, elemental, magnetic, optical, and electrical transport properties of Zn 1-x K x O (0 ≤ x ≤ 0.12) compounds for their plausible application in spintronic devices. These compounds have been crystallized in a single phase and formed with spherical particles of size 3–6 μm. At 300 K, the M − H curve reveals that undoped ZnO exhibits diamagnetism but all K-doped ZnO compounds show M − H hysteresis loops similar to ferromagnetic material with coercivity in the range of 80–140 Oe. These compounds exhibit maximum saturation magnetization of 0.04 μ B per K-ion for 6% K-doped compound. The optical band gap values of the prepared compounds are reduced as the K concentration increases. The value of transmittance was observed to enhance from 87% (for ZnO) to 92% (for 9% K-doped ZnO) sample. The Hall effect study reveals that all K-doped ZnO samples exhibit p-type nature and the carrier density (hole) increases with the increase of K concentration. [ABSTRACT FROM AUTHOR]