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Fabrication and magnetic properties of Cu50(Fe69Si10B16C5)50 thin microwires
Journal of Non-Crystalline Solids 353 (2007) 922–924 www.elsevier.com/locate/jnoncrysol
Fabrication and magnetic properties of Cu50(Fe69Si10B16C5)50 thin microwires A. Zhukov
b
a,b,c,*
, C. Garcı´a a, V. Zhukova c,d, V. Larin b, J. Gonza´lez a, J.J. del Val a, M. Knobel e, J.M. Blanco d
a Dpto. Fı´sica de Materiales, Fac. Quimicas, Universidad del Pais Vasco, 20009 San Sebastian, Spain TAMAG Ibe´rica S.L., Parque Tecnolo´gico de Miramo´n, Paseo Mikeletegi 56, 1a Planta, 20009 San Sebastian, Spain c Magnetic and Cryoelectronic Systems Ltd., Bozhenko str., 4/1, Moscow 121351, Russia d Dpto. Fı´sica Aplicada I, EUPDS, UPV/EHU, Plaza Europa 1, San Sebastia´n 20018, Spain e Instituto de Fı´sica ‘Gleb Wataghin’, Univerdsidade Estatal de Campinas, Sao Paolo, Brazil
Available online 12 February 2007
Abstract In this work, we study the granular samples of mixed Cu50(Fe69Si10B16C5)50 composition where half of alloy composition is commonly used amorphous soft magnetic material and the other half-Cu. Glass covered Cu50(Fe69Si10B16C5)50 microwires were produced and their magnetic properties were studied. The evolution of the structure after the annealing was observed using X-ray diffraction with Cu Ka radiation. The as-prepared Cu50(Fe69Si10B16C5)50 microwires present a relatively low coercivity of about 5 Oe and exhibit non-regular hysteresis loop typical behavior for two-phases systems. Annealing resulted in magnetic hardening of the samples with coercivity of about 50 Oe. The variation of the coercivity and remanent magnetization with the temperature at 5–300 K were obtained from those curves. Temperature dependence of magnetization at 5–300 K exhibits significant difference between field-cooled and zero-field cooled behaviour. Observed dependences interpreted in terms of two-phase structure of as-prepared samples and evolution of the structure under annealing. Ó 2007 Elsevier B.V. All rights reserved. PACS: 75.50.Kj; 75.60. d; 75.75.+a Keywords: Amorphous metals, metallic glasses; Magnetic properties
1. Introduction Last few years special attention has been paid to the studies of thin glass-coated microwires produced by Taylor-Ulitovski technique. The Taylor-Ulitovski technique allows the fabrication of few km long glass-coated metallic microwires with typical radius of the metallic nucleus ranging from 1 and 10 lm and the thickness of the insulating glass coating between 2 and 10 lm. This method allows * Corresponding author. Address: Dpto. Fı´sica de Materiales, Fac. Quimicas, Universidad del Pais Vasco, 20009 San Sebastian, Spain. Tel.: +34 943 018611; fax: +34 943 017130. E-mail address: [email protected] (A. Zhukov).
0022-3093/$ - see front matter Ó 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.jnoncrysol.2006.12.061
to achieve a high quenching rate and fabricate microwires with amorphous, nanocrystalline, microcrystalline or granular structure [1]. Particularly, granular alloys formed by immiscible elements (Co, Fe, Ni)–(Cu, Pt, Au, Ag) attracted recently special attention mostly because of the giant magneto-resistance (GMR) observed in such systems [2]. The GMR effect has been explained though the scattering of the electrons on grain boundaries between two phases arising in the mixed ferromagnetic–paramagnetic microstructure. Initially the thin films preparation technique such as sputtering has been used for fabrication of such systems [3]. A melt spinning has recently been employed for fabrication of Co–Cu ribbons exhibiting GMR after recrystallization of the metastable phases [3]. Although main
A. Zhukov et al. / Journal of Non-Crystalline Solids 353 (2007) 922–924
923
attention has been paid to studies of amorphous magnetically soft microwires, few attempts have been made to obtain granular or nanocrystalline microwires with unusual properties [1,4,5]. Quite recently, the production of microwires with semi-hard magnetic properties and GMR from Fe–Ni–Cu and Co–Cu alloys was reported, exhibiting coercivities of the order of 700 Oe and GMR up to 18% [4,5]. 2. Experimental results and discussion Cu50(Fe69Si10B15C5)50 thin wire a few lm in diameter covered with a thin layer of Pyrex glass have been prepared by the Taylor-Ulitovsky technique [5]. Structure and phase analysis have been checked by using a Siemens-500 X-ray diffractometer with Cu Ka ˚ ) radiation. Magnetic and magneto-transport (k = 1.54 A properties have been measured at 5–300 K using SQUID magnetometer and PPMS device. Heat treatment has been performed inside a conventional furnace up to 573 K. Magnetization curves measured at different annealing temperatures are shown in Fig. 1(a) and (b). In as-prepared sample the coercivity is of order of 5 Oe, although the hysteresis loop at all measured temperatures has the irregular shape typical for two-phase structure, as can be well appreciated in Fig. 1(b). Magnetization measured under applied magnetic field (FC) and without magnetic field (ZFC) exhibit significant difference (see Fig. 2). Coercivity, Hc, and remanent magnetization, Mr dependences obtained from the hysteresis loop measured at different temperatures are plotted in Fig. 3. Roughly monotonic increase of both decreasing the temperature is observed. After heat treatments an increase of the coercivity, Hc, is observed and the hysteresis loop shape change being more similar to the single phase alloy (Fig. 4). Like in the case of as-prepared microwires the magnetization measured under applied magnetic field (FC) and without magnetic field (ZFC) exhibit significant difference (see Fig. 5).
Fig. 2. (FC) and (ZFC) magnetization dependence on temperature in asprepared Cu50(Fe69Si10B15C5)50 microwire.
Fig. 3. Temperature dependence of coercivity, Hc, and remanent magnetization, Mr in Cu50(Fe69Si10B15C5)50 microwire.
Irregular hysteresis loop shape (Fig. 1(b)) is typical for multi-phase structure. X-ray spectra of studied samples in as-prepared state are shown in Fig. 6. Analysis of the X-ray diffraction allows us to identify four different contributions: (1) Pyrex contribution at low angles with broad maximum at 2H 22°; (2) Cu exhibiting 3 peaks at interatomic spaces, d, corresponding to 2.064, ˚ ; (3) small amount of a-Fe with 1.792 and 1.273 A ˚ and (4) amorphous halo. d = 1.979 A
Fig. 1. Magnetization curves of Cu50(Fe69Si10B15C5)50 thin microwire in as-prepared state.
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A. Zhukov et al. / Journal of Non-Crystalline Solids 353 (2007) 922–924
Fig. 4. Magnetization curves of Cu50(Fe69Si10B15C5)50 microwire annealed at 573 K.
Such crystalline structure allows explaining the shape of the hysteresis loops observed in as-prepared state. Thus, magnetically soft amorphous phase and crystalline a-Fe phase result in irregular hysteresis loop typical for twophase behavior. The inhomogeneity of as-prepared samples gives rise also to the significant difference in ZFC–FC curves. 3. Conclusions
Fig. 5. (FC) and (ZFC) magnetization dependence on temperature in annealed at 573 K Cu50(Fe69Si10B15C5)50 microwire.
We report on fabrication and characterization of a novel glass coated Cu50(Fe69Si10B15C5)50 microwire prepared out of immiscible elements by the modified Taylor-Ulitovsky method. First structure, magnetic and magneto-transport characterization have been performed. Multi-phase structure consisting of Cu, small amount of a-Fe and amorphous phase has been observed. Magnetic and transport properties of Cu50(Fe69Si10B15C5)50 microwires depend on the annealing. Thus the coercivity in as-prepared state is ranging of order of 5 Oe and can be enhanced by thermal treatments reaching values of up to 50 Oe. References
Fig. 6. X-ray diffraction spectra of as-prepared Cu50(Fe69Si10B15C5)50 microwire.
[1] A. Zhukov, J. Gonzalez, J.M. Blanco, M. Vazquez, V. Larin, J. Mater. Res. 15 (2000) 2107. [2] J.Q. Xiao, J.S. Jiang, C.L. Chien, Phys. Rev. Lett. 68 (1992) 3749. [3] P. Alia, M. Knobel, P. Tiberto, F. Vinai, Phys. Rev. 52 (1995) 15398. [4] A. Zhukov, J. Gonzalez, V. Zhukova, J. Magn. Magn. Mater. 294 (2005) 165. [5] A. Zhukov, D. Martı´n y Marero, F. Batallan, J.J. del Val, V. Zhukova, J.L. Martinez, C. Luna, J. Gonzalez, S. Kaloshkin, M. Va´zquez, Phys. Status Solidi (c) 1 (12) (2004) 3717.
Fabrication and magnetic properties of Cu50(Fe69Si10B16C5)50 thin microwires A. Zhukov
b
a,b,c,*
, C. Garcı´a a, V. Zhukova c,d, V. Larin b, J. Gonza´lez a, J.J. del Val a, M. Knobel e, J.M. Blanco d
a Dpto. Fı´sica de Materiales, Fac. Quimicas, Universidad del Pais Vasco, 20009 San Sebastian, Spain TAMAG Ibe´rica S.L., Parque Tecnolo´gico de Miramo´n, Paseo Mikeletegi 56, 1a Planta, 20009 San Sebastian, Spain c Magnetic and Cryoelectronic Systems Ltd., Bozhenko str., 4/1, Moscow 121351, Russia d Dpto. Fı´sica Aplicada I, EUPDS, UPV/EHU, Plaza Europa 1, San Sebastia´n 20018, Spain e Instituto de Fı´sica ‘Gleb Wataghin’, Univerdsidade Estatal de Campinas, Sao Paolo, Brazil
Available online 12 February 2007
Abstract In this work, we study the granular samples of mixed Cu50(Fe69Si10B16C5)50 composition where half of alloy composition is commonly used amorphous soft magnetic material and the other half-Cu. Glass covered Cu50(Fe69Si10B16C5)50 microwires were produced and their magnetic properties were studied. The evolution of the structure after the annealing was observed using X-ray diffraction with Cu Ka radiation. The as-prepared Cu50(Fe69Si10B16C5)50 microwires present a relatively low coercivity of about 5 Oe and exhibit non-regular hysteresis loop typical behavior for two-phases systems. Annealing resulted in magnetic hardening of the samples with coercivity of about 50 Oe. The variation of the coercivity and remanent magnetization with the temperature at 5–300 K were obtained from those curves. Temperature dependence of magnetization at 5–300 K exhibits significant difference between field-cooled and zero-field cooled behaviour. Observed dependences interpreted in terms of two-phase structure of as-prepared samples and evolution of the structure under annealing. Ó 2007 Elsevier B.V. All rights reserved. PACS: 75.50.Kj; 75.60. d; 75.75.+a Keywords: Amorphous metals, metallic glasses; Magnetic properties
1. Introduction Last few years special attention has been paid to the studies of thin glass-coated microwires produced by Taylor-Ulitovski technique. The Taylor-Ulitovski technique allows the fabrication of few km long glass-coated metallic microwires with typical radius of the metallic nucleus ranging from 1 and 10 lm and the thickness of the insulating glass coating between 2 and 10 lm. This method allows * Corresponding author. Address: Dpto. Fı´sica de Materiales, Fac. Quimicas, Universidad del Pais Vasco, 20009 San Sebastian, Spain. Tel.: +34 943 018611; fax: +34 943 017130. E-mail address: [email protected] (A. Zhukov).
0022-3093/$ - see front matter Ó 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.jnoncrysol.2006.12.061
to achieve a high quenching rate and fabricate microwires with amorphous, nanocrystalline, microcrystalline or granular structure [1]. Particularly, granular alloys formed by immiscible elements (Co, Fe, Ni)–(Cu, Pt, Au, Ag) attracted recently special attention mostly because of the giant magneto-resistance (GMR) observed in such systems [2]. The GMR effect has been explained though the scattering of the electrons on grain boundaries between two phases arising in the mixed ferromagnetic–paramagnetic microstructure. Initially the thin films preparation technique such as sputtering has been used for fabrication of such systems [3]. A melt spinning has recently been employed for fabrication of Co–Cu ribbons exhibiting GMR after recrystallization of the metastable phases [3]. Although main
A. Zhukov et al. / Journal of Non-Crystalline Solids 353 (2007) 922–924
923
attention has been paid to studies of amorphous magnetically soft microwires, few attempts have been made to obtain granular or nanocrystalline microwires with unusual properties [1,4,5]. Quite recently, the production of microwires with semi-hard magnetic properties and GMR from Fe–Ni–Cu and Co–Cu alloys was reported, exhibiting coercivities of the order of 700 Oe and GMR up to 18% [4,5]. 2. Experimental results and discussion Cu50(Fe69Si10B15C5)50 thin wire a few lm in diameter covered with a thin layer of Pyrex glass have been prepared by the Taylor-Ulitovsky technique [5]. Structure and phase analysis have been checked by using a Siemens-500 X-ray diffractometer with Cu Ka ˚ ) radiation. Magnetic and magneto-transport (k = 1.54 A properties have been measured at 5–300 K using SQUID magnetometer and PPMS device. Heat treatment has been performed inside a conventional furnace up to 573 K. Magnetization curves measured at different annealing temperatures are shown in Fig. 1(a) and (b). In as-prepared sample the coercivity is of order of 5 Oe, although the hysteresis loop at all measured temperatures has the irregular shape typical for two-phase structure, as can be well appreciated in Fig. 1(b). Magnetization measured under applied magnetic field (FC) and without magnetic field (ZFC) exhibit significant difference (see Fig. 2). Coercivity, Hc, and remanent magnetization, Mr dependences obtained from the hysteresis loop measured at different temperatures are plotted in Fig. 3. Roughly monotonic increase of both decreasing the temperature is observed. After heat treatments an increase of the coercivity, Hc, is observed and the hysteresis loop shape change being more similar to the single phase alloy (Fig. 4). Like in the case of as-prepared microwires the magnetization measured under applied magnetic field (FC) and without magnetic field (ZFC) exhibit significant difference (see Fig. 5).
Fig. 2. (FC) and (ZFC) magnetization dependence on temperature in asprepared Cu50(Fe69Si10B15C5)50 microwire.
Fig. 3. Temperature dependence of coercivity, Hc, and remanent magnetization, Mr in Cu50(Fe69Si10B15C5)50 microwire.
Irregular hysteresis loop shape (Fig. 1(b)) is typical for multi-phase structure. X-ray spectra of studied samples in as-prepared state are shown in Fig. 6. Analysis of the X-ray diffraction allows us to identify four different contributions: (1) Pyrex contribution at low angles with broad maximum at 2H 22°; (2) Cu exhibiting 3 peaks at interatomic spaces, d, corresponding to 2.064, ˚ ; (3) small amount of a-Fe with 1.792 and 1.273 A ˚ and (4) amorphous halo. d = 1.979 A
Fig. 1. Magnetization curves of Cu50(Fe69Si10B15C5)50 thin microwire in as-prepared state.
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A. Zhukov et al. / Journal of Non-Crystalline Solids 353 (2007) 922–924
Fig. 4. Magnetization curves of Cu50(Fe69Si10B15C5)50 microwire annealed at 573 K.
Such crystalline structure allows explaining the shape of the hysteresis loops observed in as-prepared state. Thus, magnetically soft amorphous phase and crystalline a-Fe phase result in irregular hysteresis loop typical for twophase behavior. The inhomogeneity of as-prepared samples gives rise also to the significant difference in ZFC–FC curves. 3. Conclusions
Fig. 5. (FC) and (ZFC) magnetization dependence on temperature in annealed at 573 K Cu50(Fe69Si10B15C5)50 microwire.
We report on fabrication and characterization of a novel glass coated Cu50(Fe69Si10B15C5)50 microwire prepared out of immiscible elements by the modified Taylor-Ulitovsky method. First structure, magnetic and magneto-transport characterization have been performed. Multi-phase structure consisting of Cu, small amount of a-Fe and amorphous phase has been observed. Magnetic and transport properties of Cu50(Fe69Si10B15C5)50 microwires depend on the annealing. Thus the coercivity in as-prepared state is ranging of order of 5 Oe and can be enhanced by thermal treatments reaching values of up to 50 Oe. References
Fig. 6. X-ray diffraction spectra of as-prepared Cu50(Fe69Si10B15C5)50 microwire.
[1] A. Zhukov, J. Gonzalez, J.M. Blanco, M. Vazquez, V. Larin, J. Mater. Res. 15 (2000) 2107. [2] J.Q. Xiao, J.S. Jiang, C.L. Chien, Phys. Rev. Lett. 68 (1992) 3749. [3] P. Alia, M. Knobel, P. Tiberto, F. Vinai, Phys. Rev. 52 (1995) 15398. [4] A. Zhukov, J. Gonzalez, V. Zhukova, J. Magn. Magn. Mater. 294 (2005) 165. [5] A. Zhukov, D. Martı´n y Marero, F. Batallan, J.J. del Val, V. Zhukova, J.L. Martinez, C. Luna, J. Gonzalez, S. Kaloshkin, M. Va´zquez, Phys. Status Solidi (c) 1 (12) (2004) 3717.