Assis Marcelo, Pontes Ribeiro Renan Augusto, Carvalho Maria Helena, Teixeira Mayara Mondego, Gobato Yara Galvão, Prando Gabriela Augusta, Mendonça Cleber Renato, de Boni Leonardo, Aparecido de Oliveira Adilson Jesus, Bettini Jefferson, Andrés Juan, Longo Elson
CDMF, LIEC, Chemistry Department, Federal University of São Carlos-(UFSCar), P.O. Box 676, 13565-905 São Carlos, São Paulo, Brazil.
Physics Department, Federal University of São Carlos-(UFSCar), P.O. Box 676, 13565-905 São Carlos, São Paulo, Brazil.
ACS Omega. 2020 Apr 21;5(17):10052-10067. doi: 10.1021/acsomega.0c00542. eCollection 2020 May 5.
Novel magnetic metals and metal oxides that use both the spin and charge of an electron offer exciting technological applications. Their discovery could boost research on functional nanoscale materials. Here, for the first time, we report the magnetization of α-AgWO under electron beam and femtosecond laser irradiation. The formation and growth of silver oxides (AgO, AgO, and AgO) and Ag nanofilaments can be observed on the surface of α-AgWO crystals. These features were also present in the composition of an extruded material and could open new avenues for surface magnetism studies. In order to understand these results, we used first-principles density functional theory calculations. This allowed us to investigate several potential scenarios for controlling magnetic properties. The effect of electron addition on the crystalline structures of α-AgWO, AgO, AgO, and AgO has been analyzed in detail. The creation of Ag and O vacancies on these compounds was also analyzed. Based on structural and electronic changes at the local coordination site of Ag, a mechanism was proposed. The mechanism illustrates the processes responsible for the formation and growth of metallic Ag and the magnetic response to electron beam irradiation.
利用电子自旋和电荷的新型磁性金属及金属氧化物具有令人兴奋的技术应用前景。它们的发现可能会推动功能性纳米材料的研究。在此，我们首次报道了α-AgWO在电子束和飞秒激光辐照下的磁化现象。在α-AgWO晶体表面可以观察到氧化银（AgO、Ag₂O和Ag₂O₃）和银纳米丝的形成与生长。这些特征在挤压材料的成分中也存在，并且可能为表面磁性研究开辟新途径。为了理解这些结果，我们使用了第一性原理密度泛函理论计算。这使我们能够研究几种控制磁性的潜在情况。详细分析了电子添加对α-AgWO、AgO、Ag₂O和Ag₂O₃晶体结构的影响。还分析了这些化合物上银和氧空位的产生。基于银局部配位位点的结构和电子变化，提出了一种机制。该机制阐明了金属银形成和生长以及对电子束辐照产生磁响应的过程。
