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Electronic Supplementary Material for

Tunable single-phase magnetic behavior in chemically synthesized AFeO3-

MFe2O4 (A = Bi or La, M = Co or Ni) nanocomposites

T. Sarkar1*, G. Muscas2, G. Barucca3, F. Locardi4, G. Varvaro5, D. Peddis5, R. Mathieu1

1Department of Engineering Sciences, Uppsala University, Box 534, SE-75121 Uppsala, Sweden

2Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala, Sweden

3Department SIMAU, University Politecnica delle Marche, Via Brecce Bianche, Ancona, 60131, Italy

4Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Genova, Via Dodecaneso 31,

Genova, 16146, Italy5Istituto di Struttura della Materia – CNR, Area della Ricerca di Roma1, Monterotondo Scalo, RM,

00015, Italy

*Corresponding author: tapati.sarkar@angstrom.uu.se

Electronic Supplementary Material (ESI) for Nanoscale.This journal is © The Royal Society of Chemistry 2018

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1. Synthesis

Fig. S1. Schematic diagram showing the synthesis process of CFO and NFO (left panel), and

BFO, LFO, and the nanocomposites (right panel).

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2. Structural Characterization

Fig. S2. XRPD patterns of (a) NFO/BFO with 2% NFO, (b) CFO/LFO with 2% CFO, and (c)

CFO/LFO with 10% CFO nanocomposite. The peaks corresponding to the CFO phase are

indexed in red.

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Fig. S3. XRPD patterns of BFO synthesized using ethylene glycol as the chelating agent (a)

before and (b) after washing with acetic acid. The Bi2O3 impurity is marked with a red asterisk.

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Fig. S4. XRPD patterns of BFO synthesized using glycine as the chelating agent, and annealed

at 500C (black), 550C (red), and 600C (blue). The Bi2O3 impurity is marked with a red

asterisk.

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2. Morphological Characterization

Fig. S5. TEM bright field images of CFO/LFO (10:90 by weight) nanocomposite taken at

different magnifications revealing the porous structure of the sample (red arrows) composed of

interconnected nanocrystals.

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Fig. S6. TEM analysis of CFO/LFO nanocomposite with 50% CFO. (a) TEM bright field image

of the sample, (b) the corresponding SAED pattern, (c) dark field image highlighting the

presence and distribution of LFO nanocrystals, and (d) dark field image highlighting the

presence and distribution of CFO nanocrystals.

The image in (c) was obtained using a portion of the two diffraction rings indicated by the red

circle in (b). The most intense LFO ring was taken (the larger one corresponding to the {121}

lattice planes), and also the less intense CFO ring (corresponding to the {220} lattice planes).

Thus, it is expected that the visible crystals in (c) are prevalently LFO nanocrystals. Next, the

selected area was moved in the blue circle position and also the most intense CFO diffraction

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ring was taken (corresponding to the {131} lattice planes). In (d), both the previous LFO and

the new CFO crystals are lighted. Comparing (c) and (d), it is possible to identify the CFO

nanocrystals. These images show the good dispersion of the two phases. Furthermore, SAED

measurements performed on small areas of the sample have always shown the presence of both

the phases, confirming again the excellent dispersion of the LFO and CFO nanocrystals.

Fig. S7. High resolution TEM image of a CFO (red) and an LFO (blue) nanocrystal. The fast

Fourier transform of the image reveals that the CFO crystal is in [3-32] zone axis and the LFO

in [010] zone axis.

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Fig. S8. High resolution TEM image of a CFO nanocrystal (red arrow). The fast Fourier

transform of the image reveals that the CFO crystal is in [110] zone axis.

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3. Magnetization Measurements

Magnetization versus temperature measurements were performed using zero-field-cooled

(ZFC) and field-cooled (FC) protocols (Figs. S9 and S10). ZFC and FC magnetization

measurements were performed by first cooling the sample from room temperature to 5 K in

zero magnetic field; next, a static magnetic field of 5 mT was applied. MZFC was measured

during warming up from 5 to 400 K. The sample was then cooled from 400 K to 5 K in the

presence of a static magnetic field of 5 mT, and MFC was recorded during the subsequent

warming up from 5 to 400 K.

Fig. S9. ZFC and FC magnetization versus temperature curves for (a) CFO, (b) NFO, (c) BFO,

and (d) LFO under a magnetizing field of 0.05 T.

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Fig. S10. ZFC and FC magnetization versus temperature curves for (a) CFO/BFO, (b)

NFO/BFO, (c) CFO/LFO, and (d) NFO/LFO under a magnetizing field of 0.05 T.

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Fig. S11. Isothermal magnetization curves of (a) NFO/BFO and (b) CFO/LFO nanocomposite

recorded at T = 5 K.

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Fig. S12. Normalized isothermal magnetization curves of CFO (red triangles) and CFO/LFO

composite with 10% CFO (orange inverted triangles) and 50% CFO (green circles) recorded

at T = 5 K.