Magnetotransport properties of high quality Co:ZnO and Mn:ZnO single crystal pulsed laser deposition films: Pitfalls associated with magnetotransport on high resistivity materials

John S. McCloy, Joseph V. Ryan, Timothy Droubay, Tiffany C. Kaspar, Scott Chambers, David C. Look
2010 Review of Scientific Instruments  
The electrical resistivity values for a series of pure and doped ͑Co, Mn, Al͒ ZnO epitaxial films grown by pulsed laser deposition were measured with equipment designed for determining the direct current resistivity of high resistance samples. Room-temperature resistances ranging from 7 ϫ 10 1 to 4 ϫ 10 8 ⍀ / sq were measured on vacuum-reduced cobalt-doped ZnO, ͑Al,Co͒ co-doped ZnO, pure cobalt-doped ZnO, Mn-doped ZnO, and undoped ZnO. Using a four-point collinear geometry with gold
more » ... th gold spring-loaded contacts, resistivities were measured from 295 to 5 K for resistances of Ͻ ϳ 10 12 ⍀ / sq. In addition, magnetoresistance and Hall effect were measured as a function of temperature for select samples. Throughout the investigation, samples were also measured on commercially available instrumentation with good agreement. The challenges of transport measurements on high resistivity samples are discussed, along with some offered solutions to those challenges.
doi:10.1063/1.3436648 pmid:20590247 fatcat:5w63nd2p5zcc7f2jy7r24ahymy