Abstract Single crystals of L-asparagine doped ammonium tetroxalate dihydrate were grown using slow evaporation solution growth technique with deionized water as a solvent. The shift and intensity of the peaks in the single crystal X-ray diffraction and Fourier transform infrared analyses confirmed the inclusion of L-asparagine in the ammonium tetroxalate dihydrate crystal structure. The optical transmission characteristics viz. optical band gap, optical conductivity, etc., were determined. Thermal studies revealed the occurrence of anomalies at 135.3 °C and 221.7 °C leading to the possibility of phase transitions and thereby, ferroelectric behavior. Vickers microhardness studies enabled determination of various microhardness parameters. Dielectric behavior was analyzed by varying the temperature and frequency. Anomalies were observed at 135 °C and 221 °C suggesting the existence of ferroelectric nature of the compound. Self-defocusing effect was observed. The polarization-electric field hysteresis loops showed a pinched effect due to defects induced by inclusion of dopant. The crystals were characterized by single crystal XRD, FT-IR, DRS, UV-Vis-NIR, Vickers microhardness test as well as thermal and dielectric techniques. In brief, L-asparagine as a dopant in ammonium tetroxalate dihydrate altered various physical properties of the crystals. They were highly transparent in the visible region with a wider optical band gap, softer material than the parent, higher phase transition temperature of 135 °C, negative nonlinearity and self-defocusing ability.

中文翻译：

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L-天冬酰胺掺杂对四草酸铵二水合物单晶生长及特性的影响

摘要 以去离子水为溶剂，采用缓慢蒸发溶液生长技术生长了 L-天冬酰胺掺杂四水合四酸铵单晶。单晶 X 射线衍射和傅立叶变换红外分析中峰的位移和强度证实了四草酸铵二水合物晶体结构中包含 L-天冬酰胺。光传输特性即。测定了光学带隙、光导率等。热学研究表明，在 135.3 °C 和 221.7 °C 发生异常，导致相变的可能性，从而导致铁电行为。维氏显微硬度研究能够确定各种显微硬度参数。通过改变温度和频率来分析介电行为。在 135 °C 和 221 °C 观察到异常现象，表明该化合物存在铁电性质。观察到自散焦效应。由于掺杂剂引起的缺陷，极化-电场磁滞回线显示出收缩效应。通过单晶 XRD、FT-IR、DRS、UV-Vis-NIR、维氏显微硬度测试以及热和介电技术对晶体进行表征。简而言之，L-天冬酰胺作为四草酸铵二水合物中的掺杂剂改变了晶体的各种物理性质。它们在可见光区高度透明，具有更宽的光学带隙、比母体更柔软的材料、135°C 的更高相变温度、负非线性和自散焦能力。观察到自散焦效应。由于掺杂剂引起的缺陷，极化-电场磁滞回线显示出收缩效应。通过单晶 XRD、FT-IR、DRS、UV-Vis-NIR、维氏显微硬度测试以及热和介电技术对晶体进行表征。简而言之，L-天冬酰胺作为四草酸铵二水合物中的掺杂剂改变了晶体的各种物理性质。它们在可见光区高度透明，具有更宽的光学带隙、比母体更柔软的材料、135°C 的更高相变温度、负非线性和自散焦能力。观察到自散焦效应。由于掺杂剂引起的缺陷，极化-电场磁滞回线显示出收缩效应。通过单晶 XRD、FT-IR、DRS、UV-Vis-NIR、维氏显微硬度测试以及热和介电技术对晶体进行表征。简而言之，L-天冬酰胺作为四草酸铵二水合物中的掺杂剂改变了晶体的各种物理性质。它们在可见光区高度透明，具有更宽的光学带隙、比母体更柔软的材料、135°C 的更高相变温度、负非线性和自散焦能力。维氏显微硬度测试以及热和介电技术。简而言之，L-天冬酰胺作为四草酸铵二水合物中的掺杂剂改变了晶体的各种物理性质。它们在可见光区高度透明，具有更宽的光学带隙、比母体更柔软的材料、135°C 的更高相变温度、负非线性和自散焦能力。维氏显微硬度测试以及热和介电技术。简而言之，L-天冬酰胺作为四草酸铵二水合物中的掺杂剂改变了晶体的各种物理性质。它们在可见光区高度透明，具有更宽的光学带隙、比母体更柔软的材料、135°C 的更高相变温度、负非线性和自散焦能力。