MAGNETIC AND MECHANICAL PROPERTIES OF MAGNETIC GLASS- COATED MICROWIRES WITH DIFFERENT GLASS COATING. V. Zhukova a,1 , A. Zhukov a, b , V. Larin a,c , A. Torcunov a,d , J. Gonzalez e , A. R. de Arellano Lopez f , J.J. Quispe-Cancapa f and A.R. Pinto-Gómez f . a) “TAMag Iberica” S.L., Parque Tecnológico de Miramón, Paseo Mikeletegi 56, 1ª Planta, 20009 San Sebastián, Spain b) Dpto de Física Aplicada I, EUPDS, UPV/EHU, Plaza Europa 1, San Sebastián, 20018, Spain c)”MFTI” S.R.L., 26, 39, str. Mitropolit G. Grosu, MD 2028, Kishinev, Republic of Moldova d) "AmoTec" S.R.L., 5, Miorita str., 2028 Kishinev, Republic of Moldova e)Dpto. Física de Materiales, Fac. Químicas, UPV/EHU, 1072, 20080, San Sebastián, Spain. f) Dept. Fisica de la Materia Condensada, Universidad de Sevilla, Spain 1 wupzhuka@sp.ehu.es Keywords : Glass coated microwires, magnetic bistability, tensile yield. Abstract. Glass coated microwires with two metallic nucleus compositions Co 57 Fe 6.1 Ni 10 B 15.9 Si 11 and Fe 36,4 Co 41,7 B 11,8 Si 10,1 with 3 different glass coating compositions (Pyrex – 74.5% SiO 2 , 15% - B 2 O 3 , 3%- Na 2 O, 2%- Al 2 O 3 1.5% -K 2 O; Nonex – 73% SiO 2 , 16.5% - B 2 O 3 , 6% - PbO 3 %-Na 2 O, 1.5% -K 2 O; and F1 – 70.2% SiO 2 , 27% - B 2 O 3 , 0.8 %-Na 2 O, 2%- LiO 2 1% -K 2 O;) with very similar geometry (metallic nucleus diameter 7 μm, total diameter 19 μm) have been successfully fabricated and studied. Fe- rich microwires in as-prepared state show rectangular hysteresis loops, which is connected with the strong internal stresses induced by the fabrication process. Co-rich compositions show inclined hysteresis loop with smaller value of coercive field. The coercivity, H c , of Co-rich microwires is the highest and of Fe- rich samples is the lowest in the case of Pyrex coated microwires. The Nonex coated microwires are in the intermediate position while the F1 coated Co-rich microwires have the lowest H c while the Fe-rich samples have the highest H c . The mechanical tests show that the best tensile strain yield is observed in samples coated by Nonex glass followed by Pyrex and F1. In this way the variation of the glass coating material allows to tailor both magnetic and mechanical properties of glass coated tiny microwires. Introduction Last advances in magnetic materials are based on the miniaturization of modern magnetic materials. In this way the Taylor Ulitovski method which permits to produce tiny metallic wires (in the order of 3 to 30 μm in diameter) covered by an insulating glass coating has been recently employed for fabrication of ferromagnetic microwires coated by glass, exhibiting very promising magnetic properties such as magnetic bistability, GMI effect, enhanced magnetic softness etc [1]. These properties are correlated with the shape and magnetoelastic anisotropies depending on the microstructure of the ferromagnetic nucleus, its chemical composition and strong internal stresses originated mainly from the difference of the thermal expansion coefficients of the metal and the glass (thermal stresses induced by the rapid solidification process itself are generally much lower). Consequently, the magnetic properties could be modified by either heat treatment or chemical etching of the glass coating or by the selection of adequate chemical composition of the metallic nucleus. Most early reports on glass coated microwires were devoted to the their mechanical properties[2,3]. Thus, effect of annealing and crystallization on tensile strength and Young modulus was studied in amorphous Fe-rich and stainless steel microwires produced by the Taylor- Ulitovski technique[3]. High tensile strength (around 2.5 GPa) was observed in amorphous Fe 80 P 16 C 3 B 1 microwires as-compared with the crystalline microwires (around 1.3 GPa). Such tensile strength is found to decrease increasing the metallic nucleus diameter. This tendency has been attributed to the higher cooling rate with decreasing of the metallic nucleus diameter. On the other hand, the Young modulus of amorphous samples (80 GPa) is Materials Science Forum Vols. 480-481 (2005) pp. 293-298 online at http://www.scientific.net © 2005 Trans Tech Publications, Switzerland Licensed to Zhukova (wupzhuka@sp.ehu.es) - "TAMag Iberica" S.L. - Spain All rights reserved. No part of the contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of the publisher: Trans Tech Publications Ltd, Switzerland, www.ttp.net . (ID: 158.227.162.130-27/05/05,10:23:11)