Ni-Doped SnO 2 Dilute Magnetic Semiconductors: Morphological Characteristics and Optical and Magnetic Properties
- PDF / 1,610,549 Bytes
- 8 Pages / 595.276 x 790.866 pts Page_size
- 54 Downloads / 228 Views
ORIGINAL PAPER
Ni-Doped SnO2 Dilute Magnetic Semiconductors: Morphological Characteristics and Optical and Magnetic Properties Feng Jiang 1 & Lizhi Peng 1 & Tianfu Liu 1 Received: 2 February 2020 / Accepted: 30 April 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Ni-doped SnO2 dilute magnetic semiconductors were prepared by precipitation method. The obtained spherical nanoparticles are pure tetragonal rutile phase, and Ni ions promote the growth of SnO2 nanoparticles. The optical band gap energy of the SnO2 nanoparticles decreases from 3.14 to 2.84 eV when input x% Ni. The room-temperature photoluminescence (PL) spectra and Xray photoelectron spectroscopy (XPS) confirm the existence of surface oxygen vacancies caused by the large specific surface area and the introduction of Ni ions. All the synthesized Ni-doped SnO2 nanoparticles achieve room-temperature ferromagnetism, with a saturation magnetization of up to 2.95 × 10−3 emu/g at a dopant concentration of 2%. The interaction between oxygen vacancies and Ni2+ realizes the magnetic transition of nanoparticles from diamagnetic to ferromagnetic. Keywords SnO2 nanoparticle . Morphology . Optical property . Magnetic property
1 Introduction Traditional electronic devices take advantage of the conductivity of electrons, ignoring the spin characteristics that are closely related to information manipulation and storage [1]. Spintronics is a science that studies the charge transport and spin of electrons. Finding material for new generation spintronic devices is an ongoing quest. Diluted magnetic semiconductor (DMS) with a Curie temperature (Tc) well above room temperature (RT) is considered a promising candidate. The main challenge for DMS is to achieve RT spin injection. Early DMSs have a Tc below RT, which limited its application in spintronic devices [2]. Matsumoto et al. observed long-range ferromagnetic coupling in Co-doped TiO2 films for the first time, paving the way for oxide-based DMSs [3]. Doping transition metal in oxides has achieved RT ferromagnetism, such as ZnO, In2O3, CeO2, and SnO2 [4–7]. Among these oxides, SnO2 is a natural nonstoichiometric oxide with intrinsic defects (oxygen vacancies and interstitial tin). SnO2, as a typical wide band gap (3.6 eV [8]) n-type semiconductor has widespread applications in
* Tianfu Liu [email protected] 1
School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 102488, People’s Republic of China
solar cells [9], gas sensors [10, 11], photocatalysts [12], etc. Besides, its excellent optical transmittance and low resistivity are attractive for DMSs. Usually, pure SnO2 is diamagnetic for the 4d10 electronic configuration of Sn. A density functional study showed that even pure SnO2 is magnetic due to the presence of Sn vacancy, which shows the importance of defects to ferromagnetic coupling [13]. The defects in the SnO2 are sensitive to the preparation method and environment. Mehraj et al. studied the effect of annealing temperature on magnetic properties
Data Loading...
