Pr-Fe co-doping induced room temperature multiferroic properties in SrTiO3 films
Introduction
In recent years, SrTiO3 (STO) has been greatly concerned due to its variety of outstanding physical properties: (i) an insulator-metal transition [1], (ii) the formation of a two-dimensional electron gas [2], (iii) blue light emission [3], (iv) ferroelectricity [4] and (v) ferromagnetism [5]. Most of the studies on STO mainly concentrated on the induction of a certain kind of abnormal property in above researches. With the development of the multiferroics [6], [7], the coexistence of two or more than two kinds of properties in STO will be received more extensive concern in the future [8]. In 2014, the room-temperature multiferroic properties in (Fex, Sr1-x)TiO3 thin films were reported by Kim et al.. [9]. Meanwhile, we have studied the room-temperature P-E properties of Pr-doped STO at A sites [10]. In order to achieve better multiferroic in ‘Quantum paraelectric’ STO materials and further analyze their origins, in this paper, the Pr-Fe co-doped STO films were fabricated using the co-doping methods at both A and B sites.
Section snippets
Experimental procedures
Sr0.975Pr0.025Ti1-xFexO3 (SPTFx, x=0.1, 0.2 and 0.3) films were fabricated by the metal organic deposition (MOD) method on (111) Pt/Ti/SiO2/Si substrates [10]. The microstructure of the films was characterized by X-ray diffraction (XRD, D/Max-RB) with Cu Kα radiation and atomic force microscope (AFM, Nanoscope IV). The electrical properties were evaluated with a Keithley 6517A electrometer/high-resistance meter, an Hp4194A impedance/phase analyzer and an RT66A standard ferroelectric test unit.
Results and discussion
Fig. 1 shows the typical XRD patterns of SPTFx films at room temperature. The samples possess the polycrystalline structure of pure cubic perovskite phase with no additional peaks. The lattice parameters of SPTFx (x=0.1, 0.2 and 0.3) with the increase of Fe doping amount are about 3.8978 Å, 3.9007 Å and 3.9036 Å, respectively. We can see two features: (i) the lattice parameters increase with incorporation of Fe ions in STO films and this lattice distortion is obviously related with the partly
Conclusions
In summary, SPTFx (x=0.1, 0.2 and 0.3) films were fabricated using MOD method. The changes of Fe ions have greatly influence on the structural and electromagnetic properties of the STO samples with similar Pr content, whose ferroelectric and ferromagnetic properties could be attributed to the lattice distortion, the PNRs and the indirect double exchange interaction between Fe2+ and Fe3+ with different stations through oxygen, respectively.
Acknowledgements
This work was supported by the National Science Foundation (Grant Nos. 11504090, 51302065).
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Cited by (3)
Induction and control of dielectric relaxation properties in Fe-doped nonstoichiometric SrTiO<inf>3</inf> ceramics
2020, Physics Letters, Section A: General, Atomic and Solid State PhysicsCitation Excerpt :Kim et al. reported the room-temperature multiferroic properties of (Fex, Sr1-x)TiO3 thin films in 2014 [15]. The similar results have been achieved in the Pr-Fe co-doped STO films, and their ferroelectric and ferromagnetic properties were related to the polar nanoregions (PNRs), the lattice distortion and the indirect double exchange interaction between Fe2+ and Fe3+ through oxygen in different positions, respectively [16]. It can be seen that the defects related with Fe ions are key factors to induce STO multiferroic properties.
Room temperature multiferroic properties of Fe-doped nonstoichiometric SrTiO<inf>3</inf> ceramics at both A and B sites
2019, Solid State CommunicationsEffect of Pr-Fe doping on dielectric and modulus properties of SrTiO<inf>3</inf> films
2017, Materials Chemistry and PhysicsCitation Excerpt :Kim et al. [5] reported a room temperature multiferroic properties in (Fex, Sr1-x)TiO3 thin films. Then the room temperature multiferroic properties have been further improved by Wang et al. [10] using Pr-Fe co-doping methods in STO films, but its dielectric properties have not been paid sufficient attention. For STO materials, the dielectric anomalies are attributable to the doping of impurities such as oxygen vacancies (OVs), polar nanoregions (PNRs) and defect centers [11–15], which provides people with a method to have a better understanding of the movement mechanism of charged-defects and to adjust material properties.