Correa Marcio A, Ferreira Armando, Tromer Raphael M, Machado Leonardo D, Gamino Matheus, França Junior Sergio A N, Bohn Felipe, Vaz Filipe
Departamento de Física, Universidade Federal do Rio Grande do Norte, Natal 59078-900, RN, Brazil.
Centro de Física, Universidade do Minho, 4710-057 Braga, Portugal.
Materials (Basel). 2021 Sep 16;14(18):5337. doi: 10.3390/ma14185337.
ZnO and doped ZnO films with non-ferromagnetic metal have been widely used as biosensor elements. In these studies, the electrochemical measurements are explored, though the electrical impedance of the system. In this sense, the ferromagnetic properties of the material can be used for multifunctionalization of the sensor element using external magnetic fields during the measurements. Within this context, we investigate the room-temperature ferromagnetism in pure ZnO and Ag-doped ZnO films presenting zigzag-like columnar geometry. Specifically, we focus on the films' structural and quasi-static magnetic properties and disclose that they evolve with the doping of low-Ag concentrations and the columnar geometry employed during the deposition. The magnetic characterization reveals ferromagnetic behavior at room temperature for all studied samples, including the pure ZnO one. By considering computational simulations, we address the origin of ferromagnetism in ZnO and Ag-doped ZnO and interpret our results in terms of the Zn vacancy dynamics, its substitution by an Ag atom in the site, and the influence of the columnar geometry on the magnetic properties of the films. Our findings bring to light an exciting way to induce/explore the room-temperature ferromagnetism of a non-ferromagnetic metal-doped semiconductor as a promising candidate for biosensor applications.
氧化锌以及掺杂了非铁磁性金属的氧化锌薄膜已被广泛用作生物传感器元件。在这些研究中，人们通过系统的电阻抗来探索电化学测量方法。从这个意义上说，材料的铁磁特性可用于在测量过程中利用外部磁场对传感器元件进行多功能化。在此背景下，我们研究了呈现之字形柱状结构的纯氧化锌和银掺杂氧化锌薄膜的室温铁磁性。具体而言，我们着重研究了薄膜的结构和准静态磁性能，并发现它们会随着低银浓度的掺杂以及沉积过程中采用的柱状结构而变化。磁性表征显示，所有研究样品（包括纯氧化锌样品）在室温下均呈现铁磁行为。通过考虑计算模拟，我们探讨了氧化锌和银掺杂氧化锌中铁磁性的起源，并根据锌空位动力学、银原子在该位置的取代以及柱状结构对薄膜磁性能的影响来解释我们的结果。我们的发现揭示了一种激发/探索非铁磁性金属掺杂半导体室温铁磁性的令人兴奋的方法，这种半导体有望用于生物传感器应用。
