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FERRITE FILMS WITH ORGANIC ADDITIVES
PREPARED BY FERRITE PLATING TECHNIQUE
T. Itoh, M. Abe, T. Tamaura
To cite this version:
JOURNAL DE PHYSIQUE
Colloque C8, Suppldment au no 12, Tome 49, ddcembre 1988
FERRITE FILMS WITH
ORGANICADDITIVES PREPARED BY FERRITE
PLATING TECHNIQUE
T. Itoh (I), M. Abe ( I ) and T. Tarnaura (,)
( I ) Department of Physical Electronics, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152, Japan
(2)
Department of Chemistry, Tokyo Institute of Technology, Ookayama, Meguro-Ku, Tokyo 152, JapanAbstract. - Ferrite (Fes-,O4) films added with dextran [ ( ~ ~ ~ ~01 sucrose (C12H22011) were prepared ~ 0 5 ) ~ ~ ~ ~ ~ ~ ~ ~ ~ ]
by "spin-spray" ferrite plating at 80 OC. The water-soluble additives were mixed into the rextion solution. Lattice constant, magnetization, coercive force and the ratio Fe2+/Fe3+ in the films decreased considerably by adding dextran, while they decreased slightly by adding sucrose.
1. Introduction
Ferrite plating facilitates formation of crystalline spinel films in an aqueous solution at low temperature
(< 90 OC) [I]. This enables us t o make new ferrite film devices using substrates of non-heat resisting materials such as plastics [2] or GaAs IC7s [3].
There are several methods to perform the ferrite plating [4, 51. Among them, "spin-spray" method is most advantageous for getting good quality film [5]. In this method a reaction solution containing ~ e ' + and other metal ions and also an oxidizing solution are si- multaneously sprayed onto a spinning substrate which is kept at 60
--
90 OC.In this study we have added water-soluble organic compounds, such as dextran and sucrose, into the fer- rite films by mixing the compounds into the reaction solution. Sucrose (C12H22012) catalyzes the ferrite formation reaction in the aqueous solution, changing the condition on which Fes04 is made in a Fe (OH), so- lution [6]. Sucrose makes a co-ordinated complex with iron ion, so that this organic compound is expected to remain in the ferrite film when it is mixed into the reaction solution. Similar effects are expected for dex- tran which is a polysaccharide as well as sucrose.
We describe in this paper the preparation of the films with the organic additives, and report the crys- tallographic and magnetic properties of the films.
2. Experimental
On glass and PET substrates ferrite plating was performed by "improved" spin-spray method [7]. We used a reaction solution (pH = 5.2) which con- tains FeClz-3.5Hz0 (3 g/l) and an oxidizing solu- tion (pH = 6.9) which contains NaNOk (0.5 g/l) and CH3COONH4 (5 g/l).
Into the reaction solution, we mixed sucrose (C12H22011) at 600 N 4 890 weight % (sucrose/Fe),
or we mixed dextran [ ( c ~ H ~ ~ o ~ ) ~ ~ ~ ~ , ~ ~ ~ ~ ] at 0.28 2.83 weight % (dextran/Fe). The substrate was kept
at 80 OC and spun at 300 rpm during plating. We obtained film thickness of N 0.9 pm by plating for
-
30 min.We have performed X-ray analysis using Cu-Ka! ra- diation and magnetic measurement (parallel to film plane) using a VSM with the samples plated on the glass substrates. ~e~~ Mossbauer measurement was performed using 10 mCi coS7 source on samples plated on the PET substrates. All the measurements were done a t room temperature.
3. Results
All the films exhibited X-ray diffraction diagrams characteristics for magnetite. Due to poor resolution in the diagrams, we could not tell if (210) and (213) scatterings due to y
-
FenOs phase is existing or not. As shown figure 1, the lattice constant for the film with no additive coincides with t h a t for bulk Fe304,Fig. 1.
-
Lattice constant a s a function of concentration ratio sucrose/Fe (A) or dextran/Fe ( 0 ) in reaction solution.Dotted lines show literature values for Fe304 and 7-Fe203.
C8 - 2016 JOURNAL DE PHYSIQUE
which decreases as content of the additives in the reac- tion solution increases. Compared to sucrose, dextran decreases the lattice constant strongly. Increasing the content of additives (Fig. 2a), magnetization of the sucrose-added film does not change appreciably, but that of the dextran-added film decreases rapidly, ap- proaching the value of 7
-
Fe203. Coercive force also decreases considerably by adding dextran, while it de- creases slightly by adding sucrose (Fig. 2b).Sucrose
m Dextran
a
---
-
---
-
Fig. 2. - Magnetization (M,) and coercive force ( H , ) as a function of concentration ratio sucrose/Fe(A: M., A: H,) or dextran/Fe ( 0 : M,, 0 : H,) in reaction solution. Dotted
line show literature values for Fe304 and 7
-
Fe203.Figure 3 shows Mossbauer spectra for the films pre- pared adding (a) nothing, (b) 4 890 W.% sucrose, and (c) 2.83 W.% dextran. The spectrum (a) is composed
-8 -4 0 4 8 Velocity (mmlsec)
Fig. 3. - Mijssbauer spectra of the films which were plated a t various content of the additives in t h e reaction solution.
of two sextuplet characteristics for Fe304, one with a higher hyperfine field, Hi, due to Fe3+ on the tetrahe- dral site and the other with a lower Hi due to Fe2+ and
Fe3+ on the octahedral site which exchange electrons rapidly. The intensity ratio of the two sextuplets in (b) does not differ from that in (a), though (b) has broader line widths than in (a). In (c), however, the sextuplet with the higher Hi has a stronger intensity than that with the lower Hi. Therefore, the ratio Fe2+/Fe3+ in the film does not decrease much by adding sucrose, but it does by adding dextran. This may be responsi- ble for the above observation that dextran change the lattice constant and magnetic properties of the film more strongly than sucrose.
4. Concluding remark
X-ray and magnetic measurements have shown that mixing dextran increases the amount of Fe3+ ions in the film more strongly than mixing sucrose. This may be because dextran has a stronger tendency of mak- ing a co-ordinated bond with ~ eions than sucrose. ~ + To probe this, however, we must know how much of sucrose or dextran mixed into the reaction solution remains in the film. To analyze the amount of the re- maining organic compounds is rather difficult, and we are tackling this problem.
[I] Abe, M. and Tamaura, Y., J. Appl. Phys. 55
(1984) 2614.
[2] Abe, M., Tanno, Y. and Tamaura, Y., J. Appl.
Phys. 5'7 (1985) 3795.
[3] Abe, M., Itoh, T., Tarnaura, Y., Gotoh, Y. and Gorni, M., IEEE Trans. Magn. MAG-23 (1987) 3736.
[4] Abe, M., Tamaura, Y., Gotoh, Y., Kitamura, N. and Gomi, M., J. Appl. Phys. 6 1 (3.987) 3211. [5] Abe, M., Tamaura, Y., Ohishi, M., Saitoh, T.,
Itoh, T. and Gomi, M.: IEEE Trans. Magn
MAG-623 (1987) 3432.
[6] Tamaura, Y., Chyo, G . S. and Katsura, T., Water
Res. 13 (1979) 21.
