Speaker
Description
Varying the sputtering power during magnetron reactive sputtering deposition simultaneously affects the sputtering yield of the target atoms and the degree of disorder in the films. This greatly tunes the physical properties of transition metal oxynitrides films ($TMN_xO_y$), resulting in the emergence of various interesting physical phenomena such as metal-insulator transition (MIT) and superconductor-insulator transition (SIT). In this work, a series of $ZrN_xO_y$ thin films were deposited by adjusting the rf power. Scanning Electron Microscopy (SEM) characterization of the cross-sectional and planar morphologies revealed that higher rf power led to denser film growth. The electrical transport properties of the films were measured from 300 K to 2 K using the van de Pauw (vdP) geometry configuration. Increasing rf power resulted in lower room temperature resistivity and higher deposition rates. Meanwhile, the SIT was observed with decreasing rf power. As temperature decreased, the conduction mechanism transited from metal edge conduction of MIT to Mott’s variable range hopping (Mott-VRH) mechanism. The transition temperature on the three superconducting samples increases from 2.9 K to 3.4 K with increasing rf power. Using the w function (the logarithmic derivative of T - dependent R), the dominant temperature range of the conduction mechanism for films with different sputtering powers was identified. Analysis of magnetoresistance (MR) at 2 K and 4.2 K revealed that within 9T, films exhibiting insulating characteristics displayed negative MR behavior, whereas samples undergoing SIT transition exhibited saturated positive MR, with varying saturation field strengths. This study successfully controlled the electrical transport properties of thin films by varying the sputtering power. This study could contribute to the understanding and optimization of $TMN_xO_y$ thin films for various applications, such as electronic devices and sensors.
| Submitters Country | China |
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