chemical method

    Synthesis and characterization of manganese ferrite nanoparticles obtained by electrochemical/chemical method E. Mazar´ıo, A. Mayoral, E. Salas, N. Men´endez, P. Herrasti, J. S´anchezMarcos PII: DOI: Reference:

S0264-1275(16)31205-9 doi: 10.1016/j.matdes.2016.09.031 JMADE 2281

To appear in: Received date: Revised date: Accepted date:

10 May 2016 1 September 2016 9 September 2016

Please cite this article as: E. Mazar´ıo, A. Mayoral, E. Salas, N. Men´endez, P. Herrasti, J. S´ anchez-Marcos, Synthesis and characterization of manganese ferrite nanoparticles obtained by electrochemical/chemical method, (2016), doi: 10.1016/j.matdes.2016.09.031

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT SYNTHESIS AND CHARACTERIZATION OF MANGANESE FERRRITE NANOPARTICLES OBTAINED BY ELECTROCHEMICAL/CHEMICAL

IP

T

METHOD.

1

SC R

E. Mazarío1, A. Mayoral2, E. Salas3, N. Menéndez1, P. Herrasti1, J. Sánchez-Marcos1*

Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de

2

NU

Madrid. C/ Francisco Tomás y Valiente, 7. 28049, Madrid, Spain.

Laboratorio de Microscopias Avanzadas (LMA), Instituto de Nanociencia de Aragón,

Universidad de Zaragoza, Mariano Esquillor s/n, 50018 Zaragoza. Spain. ESRF, Spline Spanish CRG Beamline European Synchrotron, F-38043 Grenoble, France.

MA

3

D

[email protected], [email protected], [email protected],

AC

CE P

TE

[email protected], [email protected], [email protected],

1

ACCEPTED MANUSCRIPT ABSTRACT

T

A combined electrochemical/chemical method was developed in order to

IP

synthesize manganese ferrite nanoparticles. The synthesis was carried out in an

SC R

electrochemical cell containing iron as anode and cathode electrodes and an electrolyte solution of manganese chloride and tetrabutyl ammonium bromide. A usual XRD, STEM compositional mapping images and ICP analysis showed the formation of spinel

NU

structure and the presence of Mn, Fe and O in the nanoparticles (NPs) with a

MA

stoichiometry Mn0.5Fe2.5O4. The nanoparticle size, shape, and morphology were characterized using electron microscopy and X-Ray absorption spectroscopy, and SQUID measurements were carried out to determine the magnetic behaviour. This

TE

D

sample was compared with a same composition manganese ferrite obtained by electrochemical synthesis.

CE P

KEYWORDS

AC

Electrochemical synthesis, superparamagnetic, nanoparticles, manganese ferrite.

2

ACCEPTED MANUSCRIPT 1.

Introduction

T

Ferrites as nanopowders, thin films, and in bulk form are among the most studied

IP

materials. Recently, ferrite nanoparticles (NPs) have been intensively investigated for

SC R

potential applications in medicine, primarily for magnetic hyperthermia [1,2], drug delivery [3], and as contrast agents in diagnostics by magnetic resonance imaging (MRI) [4]. Ferrites can be also applied in electronic devices [5] or as catalysts [6]. The

NU

different applications strongly depend on specific characteristics of the nanoparticles,

MA

such as particle size and size distribution, as well as their magnetic characteristics at room temperature.

Ferrites have a spinel structure with general formula (A1-xBX)[AxB2-x]O4. The

TE

D

oxygen atoms form cubic close packing where A and B cations occupy tetrahedral and octahedral interstitial lattice sites, represented by round and square brackets,

CE P

respectively. The degree of inversion (x) is the proportion of the divalent cation (A2+) occupying octahedral sites. Cation substitution (e.g., Mn, Co, Ni) in the spinel structure

AC

opens up the possibility of enhancing the magnetic properties by changing the chemical composition, although this strategy often results in deviation from ideal stoichiometry [7]. Among the different magnetic materials, manganese ferrite nanoparticles are of particular interest because of their moderate magnetocrystalline anisotropy and high saturation of magnetization. Furthermore, the manganese ferrite nanoparticles are biocompatible materials. MnFe2O4, has a mixed spinel structure where manganese could be Mn2+ or Mn3+. Some authors ascribed the relation between the Mn2+/Mn3+ to the inversion degree [8], due to the Mn3+ prefers the octahedral site [9]. Moreover, thermal treatment in vacuum reduces the Mn3+ to Mn2+ changing the inversion degree [10].

3

ACCEPTED MANUSCRIPT In general, manganese ferrite nanoparticles can be easily synthesized at low temperatures, for example by using simple co-precipitation [11] of metal ions including

T

Fe2+/Fe3+ and Mn2+ chloride salts. Subsequent oxidation of Fe(II) hydroxide results in

IP

direct formation of the spinel ferrite. The co-precipitation from aqueous solutions is a

SC R

relatively simple method and is therefore suitable for mass production; however, it provides only a limited control over stoichiometry, particle size and the size distribution [12].

NU

In a previous work, electrosynthesis of manganese ferrite was carried out using

MA

two anodes, iron and manganese foil, in a solution containing tetrabutyl ammonium bromide as electrolyte [4]. The results showed the synthesis of Mn0.5Fe2.5O4. This process is simple but costly due to the price and the fragility of the manganese foil. On

TE

D

the other hand, a recent publication by Mosivand et al. detailed the synthesis of cobalt ferrite nanoparticles by means of an electrochemical cell bearing two iron electrodes,

CE P

and an electrolyte solution of sodium sulfate, sodium butanoate, and cobalt sulphate heptahydrate [13]. Evidence of the cobalt ferrite nanoparticles formation was indicated

AC

in their results.

This last work aims us to prepare manganese ferrite nanoparticles using an analogous method based on the oxidation of iron foil immersed in a solution containing a manganese salt and an electrolyte. With this methodology the manganese foil in the electrochemical synthesis to produce Mn2+ in solution is replaced by a manganese salt in solution, decreasing the price of ferrite. Its compositional, morphological and structural study and its magnetic properties are discussed.

4

ACCEPTED MANUSCRIPT 2.

Materials and Methods

Manganese ferrite NPs were prepared in one step at room temperature following an

T

electrochemical route, as shown in Fig. 1. The process involved the gradual release of

IP

Fe2+ and Fe3+ ions through the solution via application of a current density to the iron

SC R

anode (8 cm2). A cylindrical counter-electrode of iron with an area of 120 cm2 was used as the cathode and placed around the anode. A current density of 50 mA/cm 2 was applied and the purity of the Fe was 99.9% (Goodfellow). The Mn2+ ions were directly

NU

obtained using manganese chloride salt in solution (0.06 M of MnCl2.4H2O). A 0.04 M

MA

solution of R4NBr (R = Butyl) was employed as a surfactant, preventing agglomeration of nanoparticles during their synthesis. The solution was magnetically stirred throughout the electrosynthesis and a synthesis time of 1800s was employed.

TE

D

Subsequently, the nanoparticles obtained were magnetically separated from the solution,

AC

CE P

washed with distilled water and dried under vacuum at 60 °C for 24h.

5

NU

SC R

IP

T

ACCEPTED MANUSCRIPT

AC

CE P

TE

D

manganese ferrite nanoparticles.

MA

Figure 1. Scheme of the setup used for the chemical/electrochemical synthesis of

6

ACCEPTED MANUSCRIPT The elemental composition of iron and manganese were measured using an inductively coupled plasma optical emission spectrometry (ICP-OES) PerkinElmer

T

Optima 2100 DV instrument. The crystalline phase and the size of the crystals of the

IP

resulting magnetic nanoparticles were measured using X-ray diffraction. XRD pattern

SC R

was recorded between 10° and 80° 2θ at a 0.04 scan step using a Bruker/Siemens D5000 diffractometer, equipped with a secondary monochromator, a SOL-X Bruker

suite based on the Rietveld method [14].

NU

detector, and a Cu Kα radiation source. The data were refined by means of the Fullprof

MA

Spherical Aberration (Cs) corrected scanning transmission electron microscopy (STEM) using a high angle annular dark field detector (HAADF) was performed on a FEI TITAN XFEG (60-300) transmission electron microscope operated at 120 kV. The

TE

D

aberrations were minimized through a CEOS aberration corrector for the electron probe allowing a point resolution of 1Å. The microscope was equipped with a Tridiem energy

CE P

filter for electron energy loss spectroscopy (EELS) measurements. Spectrum imaging and spectrum profiles were acquired using a convergence semiangle of 25 mrad, a

AC

collection angle of 80 mrad and an energy dispersion of 0.2 eV/channel. Nanoparticles size was calculated by measuring at list one hundred nanoparticles in different TEM images.

X-ray absorption near-edge spectroscopy (XANES) and extended X-ray absorption fine structure spectroscopy (EXAFS) at the Fe and Mn K-edges were performed in transmission mode at the Spanish CRG beamline (SpLine, BM25 A) of the European Synchrotron Radiation Facility (ESRF). Energy was set using a Si (111) double crystal monochromator, detuned up to a 70% of maximum in order to reject contributions from higher harmonics.

7

ACCEPTED MANUSCRIPT The XANES and EXAFS analysis were performed using the Athena and Artemis programs[15]. The oscillations were obtained after removing the background

T

with a cubic spline fitting polynomial, and the EXAFS signal [χ(k)] was obtained via

IP

normalization of the magnitude of the oscillations to the edge jump. The distribution

SC R

function around the iron and manganese atoms was calculated by the Fourier transformation of the k3-weighted EXAFS signal [k3 χ(k)]. No phase correction had been applied.

NU

Magnetic characterization was performed using the Reciprocating Sample

MA

Option (RSO) of a SQUID magnetometer (Quantum Design MPMS XL-5). The magnetization hysteresis loops M(H) were measured at room temperature and at 5 K, applying magnetic fields up to 5 T. The temperature dependence of the magnetization,

TE

D

M(T), was determined under 100 and 5 mT and over a temperature range of 5 to 400 K. Zero-field-cooling (ZFC) and field-cooling (FC) procedures were performed. The

to:

CE P

saturation magnetization, Ms, was determined by fitting the high magnetic field region

eq. 1

AC

M(H)=Ms+H

where Ms is the magnetic saturation at zero field, and  is a term related with the differential susceptibility at high fields.

8

ACCEPTED MANUSCRIPT 3.

Results and Discussion

T

Fig. 2 shows the X- Ray diffraction pattern and Rietveld refinement of the

. The average crystal size

SC R

Bragg positions of the MnFe2O4 space group 227:

IP

sample. The particles possess a cubic spinel crystal structure in agreement with the

obtained by Rietveld refinement was 16.3 (3) nm and the lattice parameter was 8.418(7) Å. In the literature are very different values for the manganese ferrite lattice parameter,

NU

from 8.50 Å of bulk ferrite [16] to 8.3711 Å [17] of nanoparticles. The diffraction

MA

pattern does not display any peaks related to manganese oxide, such as Mn3O4, a hausmanite structure and tetragonal spatial group (141:I41/amd) [18], or α-MnO2 and β-

D

MnO2 with tetragonal structure and space group 87:I4/m, 136:P42/mnm respectively,

TE

nor γ-MnO2 with a orthorhombic structure, birnessite (δ-MnO2) with a hexagonal structure or MnO with a cubic structure and space group (225:Fmm). The presence of

CE P

any iron oxide may also be discarded, except Fe3O4, which presents the same space group and very similar lattice parameter to the manganese ferrite, 8.385(1) Å [19]. Due

AC

to the extremely similar lattice parameters of manganese ferrite and magnetite along with the width of the peaks, due to nano-scale, and the analogous scattering factor of manganese and iron cations, it is not possible to guarantee unequivocally the formation of manganese ferrite.

9

ACCEPTED MANUSCRIPT

Yexp Ycal Yexp-Ycal

10

20

30

NU

SC R

I (a.u)

IP

T

Bragg position

40

50

60

70

80

0

MA

2 ( )

Figure 2. XRD patterns of manganese ferrite synthesized at room temperature. The observed, calculated, difference patterns, and Bragg positions of

are shown. The

AC

CE P

TE

D

agreement factors are RBragg = 5.41 and Rf = 2.93.

10

ACCEPTED MANUSCRIPT Fig. 3a shows a standard TEM image of the nanoparticles. They exhibited an almost spherical shape with faceted surfaces and presented a single crystal structure

T

(fig. 3b). Fig. 3c shows the particle size distribution to be in the range of 10 to 50 nm

IP

with a mean size and a standard deviation of 23(6) nm. Furthermore, the chemical

SC R

analysis was carried out by means of EELS, the results established through this showed the nanoparticles to be composed of Fe, Mn and O (Fig. 4). The quantitative analysis of the images shows a Fe/Mn ratio of 4.9, very diverse from the ratio 2 expected for a

AC

CE P

TE

D

MA

out showing a metal molar ratio of 4.2.

NU

stoichiometric spinel. In order to confirm this result, ICP-OES analysis has been carried

c)

Figure 3. a) Low-magnification image of MnxFe2-xO4. b) Cs corrected STEM-HAADF image of a nanoparticle orientated along the [211] zone axis with the FFT shown inset. c) Size histogram of nanoparticles.

11

SC R

IP

T

ACCEPTED MANUSCRIPT

Figure 4. Cs corrected STEM-HAADF image subject to analysis (white), Fe L2,3

NU

(green), O K (red) and Mn L2,3 (blue) maps. Image color intensities are normalized to present, they are not proportionate to the element amount, so it is not possible to

AC

CE P

TE

D

MA

compare each other.

12

ACCEPTED MANUSCRIPT Summarizing, XRD shows a spinel structure without impurities or other phases and both ICP and EELS analysis show the presence of Fe and Mn in a ratio that

T

suggests that a Mn0.5Fe2.5O4 ferrite has been obtained.

IP

Fig. 5 shows the XANES region of Fe K-edge spectra for samples with the same

SC R

stoichiometry obtained by electrochemical/chemical method and by the pure electrochemical method [4] together with the spectra of pure magnetite obtained also

NU

via electrochemical method [20]. As demonstrated graphically, all samples display the same behavior with the same energy edge, indicating that the oxidation state of iron is

MA

equal within the three samples, a mixture of Fe2+ and Fe3+. The EXAFS region has been studied by means of the k3-weighted Fourier transform (FT) obtained for the three

D

samples in the K-range (2-9 Å-1), inset Fig. 5. All samples show the same distances for

TE

the first and second neighbors; the first neighbor being oxygen and the second one formed by iron and oxygen, both have different distances but are similar enough to

CE P

make them indistinguishable. The intensities of both peaks, which are related with the number of neighbors, for the two samples are very similar to each other. These results

AC

indicate that samples of Mn0.5Fe2.5O4 obtained by electrochemical/chemical or electrochemical method have a very similar structure in terms of their iron environment. Furthermore, both samples are similar to the data obtained in the Fe3O4 sample, suggesting that manganese ferrites have the same structure as spinel iron oxide. Fig.6 depicts the Mn K-edge XANES spectra of the electrochemical/chemical and electrochemical samples together with MnO and Mn3O4. Energy edges of both Mn0.5Fe2.5O4 samples are between MnO with Mn2+, and Mn3O4 with 2/3 Mn3+ and 1/3 Mn2+. So manganese cations on the ferrites are like Mn2+ and Mn3+, but there are more Mn2+ than in Mn3O4. In fact, the energy edge of MnO and Mn3O4 is 6540 and 6543 eV respectively, whereas ferrites show a 6541 eV edge. Data obtained from EXAFS 13

ACCEPTED MANUSCRIPT analysis are shown in inset Fig. 6. Both samples show almost the same number of first and second neighbors for the Mn and at the same distances, indicating that from the

T

point of view of manganese environment both samples are also very similar. In

IP

summary, electrochemical/chemical and electrochemical samples show a good crystal

SC R

quality when considering Fe and Mn. Also, at it is expected, the modulus of the Fourier transform in the Fe K-edge and Mn K-edge are very similar, indicating that both, Mn and Fe, have the same environment. That means that Mn atoms are distributed in

AC

CE P

TE

D

MA

NU

octahedral and tetrahedral sites.

14

ACCEPTED MANUSCRIPT

Electrochemical/chemical Electrochemical Fe3O4

T

1.2

IP

1.0

SC R

6

0.8

5

0.6

4 3

3

FT[k  (k)]

0.4

2 1

0.2

0 0

2

0.0 7140

R(Å)

7160

MA

7120

NU

Normal XAS (arb. units)

1.4

4

6

7180

7200

Energy (eV)

D

Figure 5. Fe K-edge XANES spectra recorded on electrochemical/chemical and

TE

electrochemical manganese ferrite sample [4] and on electrochemically synthesized

AC

CE P

Fe3O4[20]. Inset shows the modulus of the Fourier transform, EXAFS region.

15

Mn3O4

1.2

MnO Electrochemical Electrochemical/chemical

0.8

IP

1.0

SC R

6 5

3

0.4

4 3 2 1

0.2

0 0

0.0 6560

2

6580

R(Å)

4

6600

6

6620

MA

6540

NU

0.6

T

1.4

FT[k (k)]

Norm. Xas (arb. units)

ACCEPTED MANUSCRIPT

Energy (eV)

D

Figure 6. Mn K-edge XANES Spectra recorded on electrochemical/chemical and

TE

electrochemical manganese ferrite sample [4] and on MnO and Mn3O4 foils. Inset

AC

CE P

shows the modulus of the Fourier transform, EXAFS region.

16

ACCEPTED MANUSCRIPT The saturation magnetizations, Ms, of ferrite were obtained fitting the magnetization versus field curves, Fig 7a, to equation 1. The values obtained for the

T

combined method are 73 and 62 emu/g from 5 and 300 K respectively. These values are

IP

smaller than those founded in the electrochemical sample [4], with 93 emu/g at 5K, but

SC R

they are high in comparison with the values obtained in the bibliography[21,22]. The coercivity field at 5 K is very small, 13 mT, whereas at 300 K is almost zero. This behavior is commonly found in superparamagnetic samples with a frozen temperature

NU

below RT.

MA

The FC magnetization curve for the two fields, 100 and 5 mT, decreases when the temperature increases as it is expected for a ferromagnetic compound, Fig 7a. The

D

magnetic transition it is not observed because it is below 400 K. Typically, two

TE

characteristic temperatures are defined in the ZFC-FC curves: TP-ZFC, which occurs at the maximum of the ZFC curves and is related to the blocking/freezing magnetic

CE P

moment of the nanoparticles; and Tirr, which occurs at the temperature where the ZFC and FC curves overlap. Both ZFC curves of Fig. 7b show a poorly defined TP-ZFC, in

AC

fact only at 100 mT is possible its calculation with a value of 80 K, and the characteristic temperature Tirr varied between both fields, from 270 K for 100 mT to 400 K for 5 mT. This behavior is attributed to the strong exchange interparticle interactions, which induce a rapid alignment of the magnetic moment even at low temperatures [23].

17

ACCEPTED MANUSCRIPT  80

 60

60



300 K

-60 0

H (mT)

100



-100

IP

-20 -40 -60

a)

-1000

0

H (mT)



NU

50 40

MA

TE

D

20

0 0

2000

b)

100 mT

30

10

1000

5 mT 200

300

400

T (K)

CE P

100



-80 -2000

M (emu/g)

5K

T

0

0

-30

SC R

M (emu/g)

20

M (emu/g)

30

40

Figure 7. a) Magnetization versus applied magnetic field at 300 K of Mn0.5Fe2.5O4 up to

AC

10000 Oe. b) Temperature dependence of the magnetization (ZFC and FC) over the temperature range of 5 to 400 K at 100 and 5 mT.

18

ACCEPTED MANUSCRIPT 4.

Conclusions

T

A combined electrochemical/chemical method has been developed for synthesize

IP

manganese ferrite nanoparticles. This is able to obtain MnxFe3-xO4 ferrite, where x =

SC R

0.5. This low amount of Mn in the structure was similar in samples obtained by electrochemical synthesis. The size of the manganese ferrite was around 23± 6 nm and X-ray diffraction confirmed the spinel structure without impurities.

NU

Mn cations were found to possess high crystallographic order with the first and second neighbor and a mixture of Mn2+ and Mn3+ was confirmed. Also XAS has demonstrated

MA

the presence of Fe2+ and Fe3+ in the structure. The comparison of nanoparticles obtained electrochemically and by the method developed in this work has shown similar

TE

D

structural and magnetic characteristics. Therefore, the most important conclusion of this work is that this methodology, which replaces the manganese anode in the

CE P

electrosynthesis process by a Mn2+ electrolyte, is perfectly viable and allows obtaining materials with the same characteristics and properties. This is a major breakthrough,

AC

taking into account the cost of the metal and its rapid degradation over time.

Acknowledgments This work was supported by the project MAT-2012-37109-C02-02. We would like to thank the Spline CRG beamline staff at ESRF for assistance during the XAS experiments.

19

ACCEPTED MANUSCRIPT 5.

References A.E. Deatsch, B.A. Evans, Heating efficiency in magnetic nanoparticle hyperthermia, J. Magn. Magn. Mater. 354 (2014) 163–172. doi:http://dx.doi.org/10.1016/j.jmmm.2013.11.006.

[2]

K. Hayashi, M. Nakamura, W. Sakamoto, T. Yogo, H. Miki, S. Ozaki, M. Abe, T. Matsumoto, K. Ishimura, Superparamagnetic nanoparticle clusters for cancer theranostics combining magnetic resonance imaging and hyperthermia treatment., Theranostics. 3 (2013) 366–76. doi:10.7150/thno.5860.

[3]

Wahajuddin, S. Arora, Superparamagnetic iron oxide nanoparticles: magnetic nanoplatforms as drug carriers., Int. J. Nanomedicine. 7 (2012) 3445–3471. doi:10.2147/IJN.S30320.

[4]

E. Mazarío, J. Sánchez-Marcos, N. Menéndez, M. Cañete, A. Mayoral, S. RiveraFernández, J.M. de la Fuente, P. Herrasti, High Specific Absorption Rate and Transverse Relaxivity Effects in Manganese Ferrite Nanoparticles Obtained by an Electrochemical Route, J. Phys. Chem. C. 119 (2015) 6828–6834. doi:10.1021/jp510937r.

[5]

N. a Frey, S. Peng, K. Cheng, S. Sun, Magnetic nanoparticles: synthesis, functionalization, and applications in bioimaging and magnetic energy storage., Chem. Soc. Rev. 38 (2009) 2532–2542. doi:10.1039/b815548h.

[6]

H. Wei, E. Wang, Fe3O4 magnetic nanoparticles as peroxidase mimetics and their applications in H2O2 and glucose detection, Anal. Chem. 80 (2008) 2250– 2254. doi:10.1021/ac702203f.

[7]

B. Antic, A. Kremenovic, A.S. Nikolic, M. Stoiljkovic, Cation distribution and size-strain microstructure analysis in ultrafine Zn-Mn ferrites obtained from acetylacetonato complexes, J. Phys. Chem. B. 108 (2004) 12646–12651. doi:10.1021/jp036214v.

[8]

K. Vamvakidis, M. Katsikini, D. Sakellari, E.C. Paloura, O. Kalogirou, C. Dendrinou-Samara, Reducing the inversion degree of MnFe 2 O 4 nanoparticles through synthesis to enhance magnetization: evaluation of their 1 H NMR relaxation and heating efficiency, Dalt. Trans. 43 (2014) 12754. doi:10.1039/C4DT00162A.

[9]

D. Carta, M.F. Casula, G. Mountjoy, A. Corrias, Formation and cation distribution in supported manganese ferrite nanoparticles: an X-ray absorption study., Phys. Chem. Chem. Phys. 10 (2008) 3108–3117. doi:10.1039/b800359a.

AC

CE P

TE

D

MA

NU

SC R

IP

T

[1]

[10] Z.J. Zhang, Z.L. Wang, B.C. Chakoumakos, J.S. Yin, Temperature Dependence of Cation Distribution and Oxidation State in Magnetic Mn - Fe Ferrite Nanocrystals, 7863 (1998) 1800–1804. [11] R. Massart, Preparation of aqueous magnetic liquids in alkaline and acidic media, IEEE Trans. Magn. 17 (1981) 1247–1248. doi:10.1109/TMAG.1981.1061188. [12] R. Galindo, N. Menendez, P. Crespo, V. Velasco, O. Bomati-Miguel, D. DíazFernández, P. Herrasti, Comparison of different methodologies for obtaining nickel nanoferrites, J. Magn. Magn. Mater. 361 (2014) 118–125. doi:10.1016/j.jmmm.2014.02.091. 20

ACCEPTED MANUSCRIPT [13] S. Mosivand, I. Kazeminezhad, Synthesis of electrocrystallized cobalt ferrite nanopowders by tuning the cobalt salt concentration, RSC Adv. 5 (2015) 14796– 14803. doi:10.1039/C4RA17162D.

T

[14] J. Rodríguez-Carvajal, Recent advances in magnetic structure determination by neutron powder diffraction, Phys. B Condens. Matter. 192 (1993) 55–69. doi:10.1016/0921-4526(93)90108-I.

SC R

IP

[15] B. Ravel, M. Newville, ATHENA, ARTEMIS, HEPHAESTUS: data analysis for X-ray absorption spectroscopy using IFEFFIT., J. Synchrotron Radiat. 12 (2005) 537–541. doi:10.1107/S0909049505012719.

NU

[16] C. Wende, K. Olimov, H. Modrow, F.E. Wagner, H. Langbein, Cation distribution, structure and magnetic properties of lithium manganese iron oxide spinel solid solutions, Mater. Res. Bull. 41 (2006) 1530–1542. doi:10.1016/j.materresbull.2006.01.016.

MA

[17] E. Solano, C. Frontera, T. Puig, X. Obradors, S. Ricart, J. Ros, Neutron and Xray diffraction study of ferrite nanocrystals obtained by microwave-assisted growth. A structural comparison with the thermal synthetic route, in: J. Appl. Crystallogr., International Union of Crystallography, 2014: pp. 414–420. doi:10.1107/S1600576713032895.

TE

D

[18] L. Sicard, J.M. Le Meins, C. Mthivier, F. Herbst, S. Ammar, Polyol synthesis and magnetic study of Mn3O4 nanocrystals of tunable size, J. Magn. Magn. Mater. 322 (2010) 2634–2640. doi:10.1016/j.jmmm.2010.03.016.

CE P

[19] M. Rivero, A. del Campo, Á. Mayoral, E. Mazario, J. Sánchez-Marcos, A. Muñoz-Bonilla, Synthesis and structural characterization of Zn x Fe3−xO4 ferrite nanoparticles obtained by an electrochemical method, RSC Adv. 6 (2016) 40067–40076. doi:10.1039/C6RA04145K.

AC

[20] L. Cabrera, S. Gutierrez, N. Menendez, M.P. Morales, P. Herrasti, Magnetite nanoparticles: Electrochemical synthesis and characterization, Electrochim. Acta. 53 (2008) 3436–3441. doi:10.1016/j.electacta.2007.12.006. [21] S. Ozcan, S. Akansel, A. Ceylan, The influence of reactive milling on the structure and magnetic properties of nanocrystalline MnFe2O4, Ceram. Int. 39 (2013) 5335–5341. doi:10.1016/j.ceramint.2012.12.039. [22] M. Muroi, R. Street, P. McCormick, J. Amighian, Magnetic properties of ultrafine MnFe2O4 powders prepared by mechanochemical processing, Phys. Rev. B. 63 (2001) 184414. doi:10.1103/PhysRevB.63.184414. [23] F. Jiménez-Villacorta, J. Sánchez-Marcos, E. Céspedes, M. García-Hernández, C. Prieto, Effects of interparticle interactions in magnetic Fe/Si3N4 granular systems, Phys. Rev. B - Condens. Matter Mater. Phys. 82 (2010) 1–12. doi:10.1103/PhysRevB.82.134413.

21

ACCEPTED MANUSCRIPT

AC

CE P

TE

D

MA

NU

SC R

IP

T

Graphical abstract

22

ACCEPTED MANUSCRIPT 

SC R NU MA D TE CE P AC



IP

T



Highlights The substitution of the manganese electrode per the manganese chloride salt allows a new cheaper method to obtain manganese ferrite nanoparticle with the same stoichiometry. The electrochemistry and electrochemistry/chemistry methods produced nanoparticles with the same environment for iron and manganese atoms, as X-Ray Absorption spectra show. Ferrite nanoparticles obtained with the new cheaper method are superparamagnetic at room temperature but shows a decrease in the magnetic saturation moment.

23