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Magnetic properties of Mo-doped TiO2 nanoparticles: A candidate for dilute magnetic semiconductors
Materials Letters 264 (2020) 127331
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/mlblue
Magnetic properties of Mo-doped TiO2 nanoparticles: A candidate for dilute magnetic semiconductors S. Ravi ⇑, F. Winfred Shashikanth Department of Physics, Mepco Schlenk Engineering College, Sivakasi 626005, India
a r t i c l e
i n f o
Article history: Received 27 November 2019 Received in revised form 6 January 2020 Accepted 8 January 2020 Available online 9 January 2020 Keywords: Magnetic materials Nanoparticles Dilute magnetic semiconductors
a b s t r a c t Emerging for future electronics, magnetic semiconductors have opened up the interest due to the preservation of both magnetic and semiconducting properties leading to multifunctional capabilities. Dilute magnetic semiconductors are one such candidate, yet it is challenging to have room temperature ferromagnetism with high Curie temperature. In this letter, we report the synthesis and characterization of pure and Mo-doped TiO2 nanoparticles (0.5% and 1%) in the anatase phase. Pure TiO2 shows diamagnetic nature. In comparison, Mo-doped TiO2 has a high Curie temperature of 400 K and exhibits roomtemperature ferromagnetism (FM) due to the overlapping and hybridization of Mo 4d and O 2p orbitals. Thus, Mo-doped TiO2 can be considered as dilute magnetic semiconductors (DMS) in future electronics. Ó 2020 Elsevier B.V. All rights reserved.
1. Introduction Dilute magnetic semiconductors (DMS) have garnered attention in the field of spintronics because they allow both spin and charge manipulation, indicating both charge and spin degree of freedom. However, room temperature FM with high Curie temperature is still an issue [1]. DMSs are formed by doping magnetic elements into semiconductor oxides. One such semiconductor oxide is TiO2 that has wide applications in various branches such as agriculture, the food industry, medicine, cosmetics, water treatment technologies, and semiconductors [2]. The crystallographic properties are also of interest because of TiO2 can exist in different phases [3]. Room temperature FM has been observed in both anatase and rutile phases of TiO2, and this magnetic behavior may be due to oxygen vacancies (VO) [4]. Moreover, many researchers have explored the magnetic, optical, and photocatalytic activities of transition elements-doped TiO2. Herein, we report Mo-doped TiO2 for their possible use as DMS. The photocatalytic nature of Mo-doped TiO2 and its application in batteries have been previously reported [5–7]; however, its magnetic properties have not been studied extensively. Z. Zou et al. [8] reported Mo and Mo codoped TiO2 in the form of films and showed the existence of
⇑ Corresponding author. E-mail address: [email protected] (S. Ravi). https://doi.org/10.1016/j.matlet.2020.127331 0167-577X/Ó 2020 Elsevier B.V. All rights reserved.
FM due to VO and doping mechanism, however, Curie temperature is not reported. Motivated by many studies on Mo doped TiO2 and Mo co-doped impurities for the possible ferromagnetism [9–13], we have prepared Mo-doped TiO2 nanoparticles as DMS material and studied its magnetic properties to understand the origin of FM in DMS. 2. Experimental To prepare pure and Mo-doped TiO2 nanoparticles, 8.5275 g of Titanium tetra isopro-oxide (99%) was mixed with 15 ml of Isopropyl alcohol (98%) and stirred for about 1 h at 70 °C. An appropriate amount of Molybdenum Nitrate (99%) was added for Mo-doped TiO2 as 0.5% and 1% wt ratio to this mixture. This was followed by the drop-wise addition of 10 ml of acetic acid (99%) that was then heated in an autoclave for 12 h at 80 °C. The dried powders were collected and calcinated for 500 °C for 2 h. The resulting powders (pure TiO2, 0.5% Mo-doped TiO2, and 1% Mo-doped TiO2) were preserved in a vacuum. The phase of the samples was investigated using X-Ray diffraction (XRD-SMART, Rikagu, Japan). Morphological images and EDS were obtained using Field emission scanning electron microscopy (FESEM, SUPRA55, Carl Zeiss, Germany). Magnetic measurements were obtained using a Super Conducting Quantum Interference Device (SQUID magnetometer, Quantum Design). X-Ray atomic absorption spectroscopy (XAS) measurements were carried out at beamline 08, Model CL4 of the
2
S. Ravi, F. Winfred Shashikanth / Materials Letters 264 (2020) 127331
national synchrotron. The normalization methods are described in our earlier report [14].
3. Results and discussion Fig. 1a shows the experimental XRD patterns of pure and Modoped TiO2 nanoparticles. The figure clearly shows that the obtained peaks matched with the anatase phase of TiO2 (shown in vertical lines) [15,16]. The additional phase is observed and indicated at peaks 27.32° in Fig. 1a; this phase is due to the MoO3 impurity phase and is insignificant due to its low intensity. Hence, the synthesized TiO2 nanoparticles are indexed predominantly in the anatase phase. The Debye-Scherrer formula gives the crystallite size of 26 nm for (1 0 1) peak estimated from the full width at half maximum. The Mo-doped samples also exhibit similar sizes with a marginal difference. No other diffraction peaks were observed, suggesting our method is a facile route to synthesize pure and Mo-doped TiO2 nanoparticles. The degree of the crystallinity is more for 1% doped TiO2 nanoparticles, due to the facile grain growth compared to 0.5% Mo doped TiO2, similar to Mo doped In2O3[17]. The ionic radii of Mo4+ are close with Ti4+, and hence, the doped sample does not show a significant change in the XRD pattern. The broadness of the observed patterns may be ascribed due to nanoparticle formation. XAS spectra of Mo-doped TiO2 was shown in Fig. 1b. The peaks observed are very similar to the MoO2 standard indicating the existence of Mo4+ states in Mo-doped TiO2. Fig. 2c is the XAS spectra of the O K edge of Mo-doped TiO2 nanoparticles compared with the TiO2 standard. There is no dramatic change in the intensity of t 2g peak for 0.5% and 1% Mo-doped TiO2 nanoparticles, which is the strong evidence for minimum VO [18] in our samples. The morphology of nanoparticles is depicted in Fig. 2. Fig. 2a is the morphology of pure TiO2 that exhibits spherical nanoparticles. Fig. 2b and c are morphological images of 1% Mo-doped sample. These images show the formation of spherical nanoparticles without any irregular structure, having sizes in good agreement with the XRD measurements. Fig. 2d is the energy dispersive spectrum of 1% Mo-doped TiO2, which shows the stoichiometric formation without any impurity. In Fig. 3a, we show the field dependence of magnetization of pure and Mo-doped TiO2 nanoparticles. The inset of Fig. 3a shows the magnetization curve for pure TiO2 nanoparticles, and it shows a negative moment indicating the diamagnetic nature of anatase TiO2. Hence, there is no charge-mediated transport or VO-induced FM [19]. The 0.5% and 1% Mo-doped TiO2 nanoparticles exhibited room temperature FM. It is also evident that as the concentration of Mo increases from 0.5% to 1%, the magnetization also increases confirming the magnetic property arises due to Mo4+ states and VO can be ruled out in accordance with the XAS result. Further, there was no change in ferromagnetic shape (Fig. 3a) and only net moment change is observed. The magnetic properties are listed in the Table 1. Hence, the FM may be due to the overlapping of Mo bands with the Ti conduction bands, leading to the upward shift of Fermi level and formation of n-type metallic type. To further analyze the magnetic property, we chose 1% Mo-doped TiO2 nanoparticles and studied the temperature dependence of magnetization (Fig. 3b). The measurement was taken in the field cooled regime by apply-
Fig. 1. (a) X-Ray diffraction patterns for pure and Mo-doped TiO2 nanoparticles indicating the formation of anatase phase with low impurity. The bottom vertical lines are standard peaks for anatase TiO2. (b) XAS Mo-K edge spectra of 0.5% and 1% doped Mo-TiO2 nanoparticles. (c) XAS O K edge spectra of Mo doped TiO2.
ing 1000 Oe. Since magnetization sharply increased at 400 K, the Curie temperature of Mo-doped TiO2 nanoparticles can be fixed at TC = 400 K, which is promising for room temperature spintronics. Below 400 K, no further anomaly or transition was observed. Thus, our samples exhibit room temperature FM for Mo-doped TiO2 with high Curie temperature. The FM is due to overlapping of Mo 4d and O 2p states as there is no charge
S. Ravi, F. Winfred Shashikanth / Materials Letters 264 (2020) 127331
3
Fig. 2. (a) SEM image for pure TiO2 nanoparticles showing the formation of spherical structure with average size of 20 nm. (b) and (c) are SEM images of Mo-doped TiO2. (d) Energy dispersive spectrum for Mo-doped TiO2 nanoparticles showing the stoichiometric formation with Mo peak of about 2.29 keV indicating the formation Mo4 + oxidation state.
mediated or VO seen for TiO2 as predicted by the ab-initio studies [13]. 4. Conclusions In summary, pure and Mo-doped TiO2 nanoparticles were synthesized by a chemical route with a particle size of about 26 nm. XRD suggested that TiO2 nanoparticles are crystallized in anatase phase with marginal impurity phase. The Mo-doped samples (0.5% and 1%) also show similar patterns that of pure TiO2 indicating the possibilities of Mo4 + replacing Ti4 + sites. The magnetic property of Mo-doped samples shows ferromagnetic nature
whereas pure TiO2 is diamagnetic. The FM behaviour arises due to magnetic Mo4+ overlapping with O 2p states and not due to VO. The Curie temperature obtained for 1% doped Mo-TiO2 is 400 K. These results are significant indicating the application of Mo-doped TiO2 in spintronics.
CRediT authorship contribution statement S. Ravi: Conceptualization, Methodology, Writing - original draft, Formal analysis. F. Winfred Shashikanth: Investigation, Data curation.
4
S. Ravi, F. Winfred Shashikanth / Materials Letters 264 (2020) 127331
Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. References
Fig. 3. (a) M H curves for Mo-doped TiO2 nanoparticles (left axis 1% and right axis 0.5%) indicating ferromagnetic hysteresis. Inset shows M H plot for pure showing diamagnetic nature. (b) M T plot for Mo-doped TiO2 showing the Curie temperature of 400 K.
Table 1 Magnetic properties of Mo-doped TiO2 nanoparticles.
0.5% Mo doped TiO2 1% Mo doped TiO2
Magnetic Saturation (Msat) (emu/g)
Retentivity (Mr) (emu/g)
Coercive Hc (Oe)
0.02044 0.08066
0.00502 0.00557
325 335
[1] S. Ravi, F. Winfred Shashikanth, Ferromagnetism in Mn doped copper oxide nanoflake likes structures with high Neel temperature, Mater. Lett. 141 (2015) 132–134. [2] M. Janus (Ed.), Application of Titanium Dioxide, Intech Open, 2017 [3] N.N. Greenwood, A. Earnshaw, Chemistry of the Elements, Pergamon Press, Oxford, 1984. [4] X. Wei, R. Skomski, B. Balamurugan, Z.G. Sun, S. Ducharme, D.J. Sellmyer, Magnetism of TiO and TiO2 nanoclusters, J. Appl. Phys. 105 (2009) 3, 07C517. [5] S. Wang, L.N. BaiH, M. Sun, Q. Jiang, S. Lian, Structure and photocatalytic property of Mo-doped TiO2 nanoparticles, Powder Technol. 244 (2013) 9–15. [6] V. Štengl, S. Bakardjieva, Molybdenum-doped anatase and its extraordinary photocatalytic activity in the degradation of orange II in the UV and vis regions, J. Phys. Chem. C 114 (45) (2010) 19308–19317. [7] Y. Xia, C. Rong, X. Yang, F. Lu, X. Kuang, Encapsulating Mo-doped TiO2 anatase in N-doped amorphous carbon with excellent lithium storage performances, Front. Mater. 6 (1) (2019) 12. [8] Z. Zou, Z. Zhou, H. Wang, Magnetic properties of Mo–N co-doped TiO2 anatase nanotubes films, J. Mater. Sci.: Mater. 28 (2017) 207–213. [9] X. Yu, T. Hou, X. Sun, Y. Li, The influence of defects on Mo-doped TiO2 by firstprinciples studies, Chemphyschem 13 (6) (2012) 1514–1521. [10] S. Roy, H. Luitel, D. Sanyal, First-principles analysis of ferromagnetic properties of molybdenum-doped wide-band-gap oxide, Phil. Mag. Lett. 99 (9) (2019) 326–337. [11] Y. Wang, R. Zhang, J. Li, L. Li, S. Lin, First-principle study on transition metaldoped anatase TiO2, Nanoscale Res. Lett. 46 (8 (2014) pages). [12] P. Murugana, R.V. Belosludov, H. Mizuseki, T. Nishimatsu, T. Fukumura, M. Kawasaki, Y. Kawazoe, Electronic and magnetic properties of doubleimpurities-doped TiO2(rutile): first-principles calculations, J. Appl. Phys. 99 (2006) 08M105. [13] A.F. Lamrani, M. Belaiche, A. Benyoussef, A.E. Kenz, E.H. Saidi, Ferromagnetism in Mo-doped TiO2 Rutile from Ab Initio, Study, J Supercond. Nov. Magn. 25 (2012) 503–507. [14] S. Ravi, F. Winfred Shashikanth, Magnetic properties of Mn-doped tellurite flakes like microstructure, Curr. Appl. Phys. 19 (2019) 1314–1317. [15] C.J. Howard, T.M. Sabine, F. Dickson, Structural and thermal parameters for rutile and anatase Locality: synthetic, Acta Crystallographica B 47 (1991) 462– 468. [16] Y.Z.C. Li, X.L.F. Gu, H. Jiang, W. Shao, L. Zhang, Y. He, Synthesis and optical properties of TiO2 nanoparticles, Mater. Lett. 61 (2007) 79–83. [17] S. Kaleemulla, N.M. Rao, M.G. Joshi, A.S. Reddy, P.S. Reddy, Electrical and optical properties of In2O3: Mo thin films prepared at various Mo-doping levels, J. Alloys Cmpd. 504 (2010) 351–356. [18] Y. Ye, M. Kapilashrami, C.-H. Chuang, Y.-S. Liu, P.-A. Glans, J. Guo, X-ray spectroscopies studies of the 3d transition metal oxides and applications of photocatalysis, MRS Commun. 7 (2017) 53–66. [19] X. Wei, R. Skomski, B. Balamurugan, Z.G. Sun, S. Ducharme, D.J. Sellmyer, Magnetism of TiO and TiO2 nanoclusters, J. Appl. Phys. 105 (2005) 3, 07C517.
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/mlblue
Magnetic properties of Mo-doped TiO2 nanoparticles: A candidate for dilute magnetic semiconductors S. Ravi ⇑, F. Winfred Shashikanth Department of Physics, Mepco Schlenk Engineering College, Sivakasi 626005, India
a r t i c l e
i n f o
Article history: Received 27 November 2019 Received in revised form 6 January 2020 Accepted 8 January 2020 Available online 9 January 2020 Keywords: Magnetic materials Nanoparticles Dilute magnetic semiconductors
a b s t r a c t Emerging for future electronics, magnetic semiconductors have opened up the interest due to the preservation of both magnetic and semiconducting properties leading to multifunctional capabilities. Dilute magnetic semiconductors are one such candidate, yet it is challenging to have room temperature ferromagnetism with high Curie temperature. In this letter, we report the synthesis and characterization of pure and Mo-doped TiO2 nanoparticles (0.5% and 1%) in the anatase phase. Pure TiO2 shows diamagnetic nature. In comparison, Mo-doped TiO2 has a high Curie temperature of 400 K and exhibits roomtemperature ferromagnetism (FM) due to the overlapping and hybridization of Mo 4d and O 2p orbitals. Thus, Mo-doped TiO2 can be considered as dilute magnetic semiconductors (DMS) in future electronics. Ó 2020 Elsevier B.V. All rights reserved.
1. Introduction Dilute magnetic semiconductors (DMS) have garnered attention in the field of spintronics because they allow both spin and charge manipulation, indicating both charge and spin degree of freedom. However, room temperature FM with high Curie temperature is still an issue [1]. DMSs are formed by doping magnetic elements into semiconductor oxides. One such semiconductor oxide is TiO2 that has wide applications in various branches such as agriculture, the food industry, medicine, cosmetics, water treatment technologies, and semiconductors [2]. The crystallographic properties are also of interest because of TiO2 can exist in different phases [3]. Room temperature FM has been observed in both anatase and rutile phases of TiO2, and this magnetic behavior may be due to oxygen vacancies (VO) [4]. Moreover, many researchers have explored the magnetic, optical, and photocatalytic activities of transition elements-doped TiO2. Herein, we report Mo-doped TiO2 for their possible use as DMS. The photocatalytic nature of Mo-doped TiO2 and its application in batteries have been previously reported [5–7]; however, its magnetic properties have not been studied extensively. Z. Zou et al. [8] reported Mo and Mo codoped TiO2 in the form of films and showed the existence of
⇑ Corresponding author. E-mail address: [email protected] (S. Ravi). https://doi.org/10.1016/j.matlet.2020.127331 0167-577X/Ó 2020 Elsevier B.V. All rights reserved.
FM due to VO and doping mechanism, however, Curie temperature is not reported. Motivated by many studies on Mo doped TiO2 and Mo co-doped impurities for the possible ferromagnetism [9–13], we have prepared Mo-doped TiO2 nanoparticles as DMS material and studied its magnetic properties to understand the origin of FM in DMS. 2. Experimental To prepare pure and Mo-doped TiO2 nanoparticles, 8.5275 g of Titanium tetra isopro-oxide (99%) was mixed with 15 ml of Isopropyl alcohol (98%) and stirred for about 1 h at 70 °C. An appropriate amount of Molybdenum Nitrate (99%) was added for Mo-doped TiO2 as 0.5% and 1% wt ratio to this mixture. This was followed by the drop-wise addition of 10 ml of acetic acid (99%) that was then heated in an autoclave for 12 h at 80 °C. The dried powders were collected and calcinated for 500 °C for 2 h. The resulting powders (pure TiO2, 0.5% Mo-doped TiO2, and 1% Mo-doped TiO2) were preserved in a vacuum. The phase of the samples was investigated using X-Ray diffraction (XRD-SMART, Rikagu, Japan). Morphological images and EDS were obtained using Field emission scanning electron microscopy (FESEM, SUPRA55, Carl Zeiss, Germany). Magnetic measurements were obtained using a Super Conducting Quantum Interference Device (SQUID magnetometer, Quantum Design). X-Ray atomic absorption spectroscopy (XAS) measurements were carried out at beamline 08, Model CL4 of the
2
S. Ravi, F. Winfred Shashikanth / Materials Letters 264 (2020) 127331
national synchrotron. The normalization methods are described in our earlier report [14].
3. Results and discussion Fig. 1a shows the experimental XRD patterns of pure and Modoped TiO2 nanoparticles. The figure clearly shows that the obtained peaks matched with the anatase phase of TiO2 (shown in vertical lines) [15,16]. The additional phase is observed and indicated at peaks 27.32° in Fig. 1a; this phase is due to the MoO3 impurity phase and is insignificant due to its low intensity. Hence, the synthesized TiO2 nanoparticles are indexed predominantly in the anatase phase. The Debye-Scherrer formula gives the crystallite size of 26 nm for (1 0 1) peak estimated from the full width at half maximum. The Mo-doped samples also exhibit similar sizes with a marginal difference. No other diffraction peaks were observed, suggesting our method is a facile route to synthesize pure and Mo-doped TiO2 nanoparticles. The degree of the crystallinity is more for 1% doped TiO2 nanoparticles, due to the facile grain growth compared to 0.5% Mo doped TiO2, similar to Mo doped In2O3[17]. The ionic radii of Mo4+ are close with Ti4+, and hence, the doped sample does not show a significant change in the XRD pattern. The broadness of the observed patterns may be ascribed due to nanoparticle formation. XAS spectra of Mo-doped TiO2 was shown in Fig. 1b. The peaks observed are very similar to the MoO2 standard indicating the existence of Mo4+ states in Mo-doped TiO2. Fig. 2c is the XAS spectra of the O K edge of Mo-doped TiO2 nanoparticles compared with the TiO2 standard. There is no dramatic change in the intensity of t 2g peak for 0.5% and 1% Mo-doped TiO2 nanoparticles, which is the strong evidence for minimum VO [18] in our samples. The morphology of nanoparticles is depicted in Fig. 2. Fig. 2a is the morphology of pure TiO2 that exhibits spherical nanoparticles. Fig. 2b and c are morphological images of 1% Mo-doped sample. These images show the formation of spherical nanoparticles without any irregular structure, having sizes in good agreement with the XRD measurements. Fig. 2d is the energy dispersive spectrum of 1% Mo-doped TiO2, which shows the stoichiometric formation without any impurity. In Fig. 3a, we show the field dependence of magnetization of pure and Mo-doped TiO2 nanoparticles. The inset of Fig. 3a shows the magnetization curve for pure TiO2 nanoparticles, and it shows a negative moment indicating the diamagnetic nature of anatase TiO2. Hence, there is no charge-mediated transport or VO-induced FM [19]. The 0.5% and 1% Mo-doped TiO2 nanoparticles exhibited room temperature FM. It is also evident that as the concentration of Mo increases from 0.5% to 1%, the magnetization also increases confirming the magnetic property arises due to Mo4+ states and VO can be ruled out in accordance with the XAS result. Further, there was no change in ferromagnetic shape (Fig. 3a) and only net moment change is observed. The magnetic properties are listed in the Table 1. Hence, the FM may be due to the overlapping of Mo bands with the Ti conduction bands, leading to the upward shift of Fermi level and formation of n-type metallic type. To further analyze the magnetic property, we chose 1% Mo-doped TiO2 nanoparticles and studied the temperature dependence of magnetization (Fig. 3b). The measurement was taken in the field cooled regime by apply-
Fig. 1. (a) X-Ray diffraction patterns for pure and Mo-doped TiO2 nanoparticles indicating the formation of anatase phase with low impurity. The bottom vertical lines are standard peaks for anatase TiO2. (b) XAS Mo-K edge spectra of 0.5% and 1% doped Mo-TiO2 nanoparticles. (c) XAS O K edge spectra of Mo doped TiO2.
ing 1000 Oe. Since magnetization sharply increased at 400 K, the Curie temperature of Mo-doped TiO2 nanoparticles can be fixed at TC = 400 K, which is promising for room temperature spintronics. Below 400 K, no further anomaly or transition was observed. Thus, our samples exhibit room temperature FM for Mo-doped TiO2 with high Curie temperature. The FM is due to overlapping of Mo 4d and O 2p states as there is no charge
S. Ravi, F. Winfred Shashikanth / Materials Letters 264 (2020) 127331
3
Fig. 2. (a) SEM image for pure TiO2 nanoparticles showing the formation of spherical structure with average size of 20 nm. (b) and (c) are SEM images of Mo-doped TiO2. (d) Energy dispersive spectrum for Mo-doped TiO2 nanoparticles showing the stoichiometric formation with Mo peak of about 2.29 keV indicating the formation Mo4 + oxidation state.
mediated or VO seen for TiO2 as predicted by the ab-initio studies [13]. 4. Conclusions In summary, pure and Mo-doped TiO2 nanoparticles were synthesized by a chemical route with a particle size of about 26 nm. XRD suggested that TiO2 nanoparticles are crystallized in anatase phase with marginal impurity phase. The Mo-doped samples (0.5% and 1%) also show similar patterns that of pure TiO2 indicating the possibilities of Mo4 + replacing Ti4 + sites. The magnetic property of Mo-doped samples shows ferromagnetic nature
whereas pure TiO2 is diamagnetic. The FM behaviour arises due to magnetic Mo4+ overlapping with O 2p states and not due to VO. The Curie temperature obtained for 1% doped Mo-TiO2 is 400 K. These results are significant indicating the application of Mo-doped TiO2 in spintronics.
CRediT authorship contribution statement S. Ravi: Conceptualization, Methodology, Writing - original draft, Formal analysis. F. Winfred Shashikanth: Investigation, Data curation.
4
S. Ravi, F. Winfred Shashikanth / Materials Letters 264 (2020) 127331
Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. References
Fig. 3. (a) M H curves for Mo-doped TiO2 nanoparticles (left axis 1% and right axis 0.5%) indicating ferromagnetic hysteresis. Inset shows M H plot for pure showing diamagnetic nature. (b) M T plot for Mo-doped TiO2 showing the Curie temperature of 400 K.
Table 1 Magnetic properties of Mo-doped TiO2 nanoparticles.
0.5% Mo doped TiO2 1% Mo doped TiO2
Magnetic Saturation (Msat) (emu/g)
Retentivity (Mr) (emu/g)
Coercive Hc (Oe)
0.02044 0.08066
0.00502 0.00557
325 335
[1] S. Ravi, F. Winfred Shashikanth, Ferromagnetism in Mn doped copper oxide nanoflake likes structures with high Neel temperature, Mater. Lett. 141 (2015) 132–134. [2] M. Janus (Ed.), Application of Titanium Dioxide, Intech Open, 2017 [3] N.N. Greenwood, A. Earnshaw, Chemistry of the Elements, Pergamon Press, Oxford, 1984. [4] X. Wei, R. Skomski, B. Balamurugan, Z.G. Sun, S. Ducharme, D.J. Sellmyer, Magnetism of TiO and TiO2 nanoclusters, J. Appl. Phys. 105 (2009) 3, 07C517. [5] S. Wang, L.N. BaiH, M. Sun, Q. Jiang, S. Lian, Structure and photocatalytic property of Mo-doped TiO2 nanoparticles, Powder Technol. 244 (2013) 9–15. [6] V. Štengl, S. Bakardjieva, Molybdenum-doped anatase and its extraordinary photocatalytic activity in the degradation of orange II in the UV and vis regions, J. Phys. Chem. C 114 (45) (2010) 19308–19317. [7] Y. Xia, C. Rong, X. Yang, F. Lu, X. Kuang, Encapsulating Mo-doped TiO2 anatase in N-doped amorphous carbon with excellent lithium storage performances, Front. Mater. 6 (1) (2019) 12. [8] Z. Zou, Z. Zhou, H. Wang, Magnetic properties of Mo–N co-doped TiO2 anatase nanotubes films, J. Mater. Sci.: Mater. 28 (2017) 207–213. [9] X. Yu, T. Hou, X. Sun, Y. Li, The influence of defects on Mo-doped TiO2 by firstprinciples studies, Chemphyschem 13 (6) (2012) 1514–1521. [10] S. Roy, H. Luitel, D. Sanyal, First-principles analysis of ferromagnetic properties of molybdenum-doped wide-band-gap oxide, Phil. Mag. Lett. 99 (9) (2019) 326–337. [11] Y. Wang, R. Zhang, J. Li, L. Li, S. Lin, First-principle study on transition metaldoped anatase TiO2, Nanoscale Res. Lett. 46 (8 (2014) pages). [12] P. Murugana, R.V. Belosludov, H. Mizuseki, T. Nishimatsu, T. Fukumura, M. Kawasaki, Y. Kawazoe, Electronic and magnetic properties of doubleimpurities-doped TiO2(rutile): first-principles calculations, J. Appl. Phys. 99 (2006) 08M105. [13] A.F. Lamrani, M. Belaiche, A. Benyoussef, A.E. Kenz, E.H. Saidi, Ferromagnetism in Mo-doped TiO2 Rutile from Ab Initio, Study, J Supercond. Nov. Magn. 25 (2012) 503–507. [14] S. Ravi, F. Winfred Shashikanth, Magnetic properties of Mn-doped tellurite flakes like microstructure, Curr. Appl. Phys. 19 (2019) 1314–1317. [15] C.J. Howard, T.M. Sabine, F. Dickson, Structural and thermal parameters for rutile and anatase Locality: synthetic, Acta Crystallographica B 47 (1991) 462– 468. [16] Y.Z.C. Li, X.L.F. Gu, H. Jiang, W. Shao, L. Zhang, Y. He, Synthesis and optical properties of TiO2 nanoparticles, Mater. Lett. 61 (2007) 79–83. [17] S. Kaleemulla, N.M. Rao, M.G. Joshi, A.S. Reddy, P.S. Reddy, Electrical and optical properties of In2O3: Mo thin films prepared at various Mo-doping levels, J. Alloys Cmpd. 504 (2010) 351–356. [18] Y. Ye, M. Kapilashrami, C.-H. Chuang, Y.-S. Liu, P.-A. Glans, J. Guo, X-ray spectroscopies studies of the 3d transition metal oxides and applications of photocatalysis, MRS Commun. 7 (2017) 53–66. [19] X. Wei, R. Skomski, B. Balamurugan, Z.G. Sun, S. Ducharme, D.J. Sellmyer, Magnetism of TiO and TiO2 nanoclusters, J. Appl. Phys. 105 (2005) 3, 07C517.