Characterization of epitaxial Cr thin films

Abstract

Thin films and heterostructures of Cr and Cr alloys show fascinating properties that is not observed in the bulk material and research into their magnetic properties gives insight into dimensionality effects in these materials. This paper reports on the characterization of Cr thin films on MgO(100), MgO(110) and fused silica substrates, of thicknesses 20nm to 320nm. X-ray diffraction (XRD) results showed good epitaxial growth for films prepared on the single-crystalline MgO substrates, with Cr(002) and Cr(211), whilst those prepared on the polycrystalline fused silica were polycrystalline. The mosaicity and coherence length were determined from the XRD results. Standard four-point probe measurements were performed to obtain the resistance (R) of the films as function of temperature (T) the anomaly in the (T) curves was used to determine the Néel temperature (TN). TN versus t graphs for the various substrates show the behaviour expected for the samples prepared on MgO(110) and fused silica substrates, but rather unique behaviour is seen in this curve for samples prepared on MgO(100). This might be attributed to internal strain effects in these thin films.