Điều khiển công nghệ chế tạo và nghiên cứu các cơ chế từ giảo từ trở dị hướng từ vuông góc trong các màng mỏng terfecohan

DAI HOC QUCC GIA HA NOI TrUdng Dai hoc Khoa hoc TiT nhicn * ^ ^ ^ i - TEN DE TAI ^ ^ - -' OIEU KHIEN CONG NGHE CHE TAG VA NGHIEN CUU CA( CO CHE TO GIAG, TO TR6 Dj HUONG TU VUONG GOG TRONG GAG MANG MONG Terfecohan MA SO QG 02-06 CHUTRiDfiTAi: PGS.TS N G U Y I N H O U DLTC HA NO! - 2003 DAI HOC QUOC GIA HA NOI • • • Trtrdng Dai hoc Khoa hoc Jxi nhien TfiN D^ TAI ^ DIEU KHIEN CONG NGHE CHE TAG VA NGHIEN CUU CAC • • CO CHE TU GIAO, TU TPd DJ H U N G TD V U O N G GOC * TRONG CAC MANG MONG Terfecohan MA so QG 02-06 PT//f^4 -J CHUTRlDgTAl: PGS.TS N G U Y I N HOU OLTC CAC CAN BO PHOI HOP THlTC HlfiN NCS D6 Thi Huong Giang Khoa vat ly, DHKHTN, DHQGHN CN Vu Nguyen Thurc Khoa Vat ly, DHKHTN, DHQGHN NCS Nguyen Tlij Minh Hong Khoa Vat ly, DHKHTN, DHQGHN CN Nguyin Thanh Trung Khoa Vat ly, DHKHTN, DHQGHN GS.TSKH Nguyin Chau Khoa Vat ly, DHKHTN, DHQGHN TS LeVanVu Khoa Vat ly, DHKHTN, DHQGHN ThS Chii Due Tiinh Khoa Cong nghe, DHQGHN CN.Vu Due Hung Khoa Cong nghe, DHQGHN HA NOI - 2003 I BAO CAO TOM TAT TflND^TAI: "Dieu khien cong nghe che tao vd nghien cihi cdc ccf che ti( gido, tif trd, di hu&ng tit vuong goc cdc mdng mong Terfecohan " MASd: QG.02-06 CHUTRID^TAI PGS TS Nguyin HSu Dire CAC CAN BO PHOI HOP THUC HIEN / NCS DS Thi Huang Giang Khoa Vat ly, DHKHTN, DHQGHN CN Vu Nguyen Thi'fc Khoa Vat ly, DHKHTN, DHQGHN NCS Nguyin Thi Minh Hong Khoa Vat ly, DHKHTN, DHQGHN CN Nguyen Thanh Trung Khoa Vat ly, DHKIH^N, DHQGHN GS.TSKH Nguyin Chdu Khoa Vat ly, DHKITTN, DHQGHN Khoa Vat ly, DHKHTN, DHQGHN TS.LeVdnVa ThS ChuDifc Tiinh Khoa Cong nghe Thong tin, DHQGHN CN.Vu Due Hung Khoa Cong nghe Thong tin, DHQGHN MUC Tl£U VA NOI DUNG NGHlfiN CUU: 5.1 Muc tieu nghien cihi cua de tai - Nghien ciiu cc che' vat ly, ndng cao tinh chat tit gido, tvt tra vd khd ndng ghi tH quang cua vat lieu - Tim kiem cdc I inh chat tilt nun - Che tqo duc/c cdc vdt lieu co khd ndng ung dung - Ddo tqo cdn bg vd nguon luc khoa hoc tre 5.2 Noi dung nghien cuu da dang ky cua de tai - Ngidung 1: Nghien cicu ca che ti( gido khong IS cdc vdt lieu TerfecoHan co di hu&ng tut vuong goc (cache quay momen tit) ' Ngi dung2: Khdo sat tinh chat tvt trd cua cdc mang mong da l&p chi(a TerfecoHan - Ngi dung 3: Tang cudng l&n cua di htccnxg tit vuong goc va luc khdng tit cdc mdng mong TerfecoHan CAC Kl^T QUA DAT DirOC: 6.1 Ket qua nghien curu: Da che' tao cong cdc mang mong tit dua tren hop chat TerfercoHan: cdc mang dan l&p TerfecoHan, da l&p TerfecoHanlYFe, TerfecoHanlYFeCo vd ba l&p FelTerfecoHanlFe tren thiet bi phun xq catot tai Trung tdm Khoa hoc Vat lieu, Khpa Vat ly, Dai hoc Khoa hoc Tu nhien, Dai hoc Quoc gia Ha Ngi Cdc mdng mong TerfecoHan dan l&j? co di hu&ng tit vuong g()c Qua trinh tit hod cdc mdng mong la qua trinh quay momen tit tit phuang vuong goc v&i mat phdng mdng sang phuang mat phdng mdng Tit gido khong 16 dqt dugc vao cd 10^ nhu'ng bao hod a tit fru'&ng cao (/.ijl > 0,6 T) /1 J Trong cdc mdng mong ba l&p (sandwich) FelTerfecoHanlFe v&i chieu day l&f) Fe (tfrj tit nm den 20 nm, momen tit cua cdc l&i? Fe nam mat phdng mdng nhung momen tit cua cdc l&p TerfecoHan lech khoi mat phdng mdng Cd'u true tit nhu vqy cho phep gid thiet su ton tai cua mot cau true domen dang 90"^ a cdc interfaces Do cung la nguyen nhdn lam gidm tit truang bdo hod vd thuc day qua trinh quay xdy tqi tit Iru&ng thdp han vd tit gido phdt trien nhanh atittrU&ng thdp Cdc mdu ba l&p u a nhiet T^ 250 V, di hu&ng tit vuong goc fqi phdt trien mqnh tren cdc mdng mong ba hrj) Ngodi lite khdng tit vuong goc dqt duac t&i gid ^t'i (MJ^C ^ 500 mT) Cdc thong sdndy thod man dieu kien ung dung cho ghi tit vuong goc Ve mat vdt ly, ca che luc khdng tvt vuong goc cao da duac gidi thich bang sU hinh cdu true nano l&p Fe a tren he mat Ket qud da duac khdng dinh bang cdc nghien citu dnh hien vi dien tu truyen qua 11-3J Cdc ddc trung tit - dien tra tren cdc mdng da l&p TerfecoHanlYFe vd TerfecoHanlYFeCo da duac khdo sdt Du&ng cong tit tri R(H) cd dqng gidng nhu du&ng cong tit gido /lf//j, nhien, he so tit - dien tra chl dqt cue dqi MR = 0,2% Ket qud cho phep nhdn xet rang, cdu hinh tit vuong goc cdc mdng mong da l&p co the duac xem xet nhu la cdu hinh cua dien trd l&n, Du&i tdc dung cua tit tru&ng ngodi, cdu true tit ddi song song v&i dien tra be Do Id khd ndng tiem an cua mot cdu hinh tit - dien trd m&i Tuy nhien, cdc vat lieu dang xet, cdc dien tu4fc6 linh dgng thdp, nen he so tit - dien trd quan sdt duac co gid tri be Cdc nghien citu cdc vdt lieu CO ndng ddt hiem thdp han la rdt cdn thiet de khang dinh gid thiet [4,5] Cdc nghien cuu cdu true vi mo, tinh chdt tit, tit gido vd ca che tie mem cdc mdng mong da l&p TerfecoHanlYFe vd TerfecoHanlYFeCo la mot ket qud vuat ngodi khuon kho da dang ki cua de tdi nhung co y nghia rdt ddc biet [6,9] Trong cdc nghien citu nay, chung tdi da tqo duac trqng thdi nano tu nhien cdc l&p tut mem cua mdng mong da l&p TerfecoHanlYFe vd TerfecoHanlYFeCo Do Id trqng thdi nano nhdn duac khong cdn u nhiet ma chl cdn dieu khien phdn Y Day cung la mot cdc tie}? can m&i, mang dam y tuang Viet Nam Cdc vdt lieu che tqo duac cd tinh chdt tit vd tit gido sieu mem (fij^c = A-? rfiT) vd cam tit gido l&n Xxu = 29x10^ T \ l&n gdp gdn 30 Ian so v&i gid tri cua cdc vdt lieu Terfenol-D quen thugc Cdc ket qud da dugc mo td dua tren cdu true tinh the gidn doqn cdc hrj? Y(Fe,Co) 16-9] Vdt lieu tit gido che tqo duac da duac sit dung de che tqo sensa tit tru&ng dua tren hieu itng tit gido - dp dien Cung voi mot bo khuyech dqi dien tich tu che'tqo, sensa tit gido dp dien co the sit dung de dd tittrit&ng 6.2 Cac cong trinh khoa hoc da cong bo: 10 cong trinh dd cong bd tren cdc tap chi Khoa hoc vd cdc Hoi nghi Khoa hoc nii&c va qudc te Magnetisation process and magnetostriction in FelTerfecohanlFe sandwich films with perpendicular N.H Due, V.N Thuc, D.T Huong Giang, NT Minh Hong and N Chau Physica 6327(2003)328 Magnetisation process in FelTerfecohanlFe sandwich films D.T Huong Giang, N.T Trung and N.H Due VNU Journal of Science, Mathematics - Physics, 2003, dang in Magnetisation and magnetostriction in FelTerfecohanlFe sandwich films with an extended domain wall formation N.H Due, D.T Huong Giang, V.N Thuc, I Davoli and F Richomme Presented in the International Conference on Magnetism, Rome 2003, to be published in J Magn Magn Mater., 2004 Spintronics dua tren tren hieu itng tit - dien tra du&ng ngdm vd khd ndng irng dung Nguyin Hull Due Tuyen t$p Hoi nghi Khoa hoc va Cong nghe Nano, Ha Noi, 5/2003, tr 48 Dieu khien cdu trdc vi mo vd cdu true tit cua cdc mdng mong co cdu trdc nano nhdn tqo dqng l&p ddt hiem - kim loqi chuyen tiep Nguyen HOii Dire Se in trong: Tuyen tap Hoi nghi Vdt ly Chdt ran todn qudc Idn tint IV, Niii Coc 5-7/11/2003 Nanostructure and magnetic TerfecohanlYFeCo multilayers softness of magnetostrictive D.T Huong Giang, N.H Due, F Richommer and S Schulze J Magn Magn Mater., 262 (2003) 361 Nanostructure and magnetic softness of magnetostrictive {TerfecohanlYFeCo} multilayers D.T Huong Giang, N.H Due, F Richommer, N.T Hien and S Schulze Proceedings of The Sixth German - Vietnamese Seminar on Physics and Engineering, Chemnitz, Germany, 25 May - 31 May, 2003 Vdt lieu tit gido kieu spring - magnet TerfecohanlYFeCo D6 Thi Hircng Giang, Nguyin Hun Dire, Vu Nguyen ThiJc Se in trong: Tuyen tap Hoi nghi Vdt ly Chdt ran todn qudc Ian tint IV, Niii Coc 5-7/11/2003 Natural nanostructure and magnetization reversal process in TbFeColYJFeCo)j.j, spring - magnets type multilayers N.H Due, D.T Huong Giang and N Chau Presented at the International Symposium on Advanced Magnetic Technology, Taipei 2003, to be published in J Magn Magn Mater., 2004 10 Sensa tit tru&ng dua tren hieu itng tit gido - dp dien Nguyin Thi Minh Hong, D6 Thi Huofng Giang, Vu Nguyen Thiic, Chu Diic Trinh, Vu Dure Hirng, Nguyin Hun Du-c Se in trong: Tuyen tap Hoi nghi Vat ly Chdt ran todn qudc Idn thit IV, Niii Coc 5-7/11/2003 6.3 Ket qua dao tao: 6.3 J - DdThi Huang Giang 6.3.2 - (dang thuc hien) Thqc sy: 01 Vil Nguyen Thitc 6.3.3 - Tien sy: 01 (dang thuc hien) Cii nhdn: 06 va Nguyen Thitc Khoa Vdt ly, DHKHTN, DHQGHN Nguyen Thanh Hdi Khoa Vdt ly, DHKHTN, DHQGHN Nguyen Thi Minh Hong Khoa Vdt ly, DHKHTN, DHQGHN Nguyen Thanh Trung Khoa Vdt ly, DHKHTN, DHQGHN Dqng Thi Minh Hong Khoa Vat ly, DHKHTN, DHQGHN va Ditc Hung Khoa Cong nghe, DHQGH 6.3.4 Sinh vien nghien cihi khoa hoc: Da hiring dan 05 sinh vien nghien cuu khoa hoc, do: - 01 sinh vien dqt gidi nhi cap Bo GD&DT nam 2002 - 01 sinh vien dqt gidi ba cap TrU&ng Dqi hgc Khoa hgc Tu nhien nam 2003 TINH HINH THANH QUYET TOAN KINH PHI: Tong kinh phi duac cap: 60 trieu dong - Nam 2001: 45 trieu dong Dd nhdn vd quyet todn day du - Nam 2002: 15 trieu dong Dd nhdn vd quyet todn day du Ha Ngi, ngdy 30 thdng 11 nam 2003 CHU TRI DE TAI XAC NHAN CUA BAN CHU NHIEM KHOA K TS Nguyen The Binh PGS.TS Nguyin HUu Dice XAC NHAN CUA TRUING IL SUMMARY OF THE REPORT TITLE OF THE PROJECT: ''Control preparation technologies and study mechanisms of magnetostriction, magnetoresistance and perpendicular anisotropy in TerfecoHan - based films'* CODE OF THE PROJECT: QG 02-06 DIRECTOR OF THE PROJECT: Assoc Prof Dr Nguyen Huu Due PARTICIPANTS IN THE PROJECT: PhD Student Do Thi Huong Giang Departement of Physics, HUS, VNU BSc Vu Nguyen Thuc Departement of Physics, HUS, VNU PhD Student Nguyen Thi Minh Hong Departement of Physics, HUS, VNU BSc Nguyen Thanh Trung Departement of Physics, HUS, VNU Prof Dr Nguyen Chau Departement of Physics, HUS, VNU Departement of Physics, HUS, VNU Dr.LeVanVu Faculty of Technology, VNU MSc Chu Due Trinh Faculty of Technology, VNU BSc Vu Due Hung OBJECTIVES AND CONTENTS: 5.1 Objectives: - To study physical mechanisms, improve magnetostrictive and magfietoresistive properties and magneto-optical recording potential of materials - To investigate novel magnetic properties - To prepare materials with high application potentials - To train young scientist resources 5.2 Contents: - Study mechanism of giant magnetostriction with perpendicular - in TerfecoHan-based films anisotropy Study magnetoresistive properties of multilayer thin films based on TerfecoHan - Improve the strength TerfecoHan-based of anisotropy and coercivity force in films OBTAINED RERULTS: 6.1 Scientific results : Magnetic films based on TerfecoHan compound consisting of single layer films, multilayer TerfecoHanlYFe TerfecoHan and TerfecoHanlYFeCo and three-layer (sandwich) FelTerfecoHanlFe films have been films successfully prepared by using RF-magnetron sputtering machine in Center of Materials Science, Department of Physics, Hanoi College of Science, Single layer TerfecoHan films VNU exhibit a perpendicular anisotropy The magnetisation process in these thin films can be described by the rotation of magnetic moments Magnetostriction from reaches out-of-plane a giant into value the film of about plane 10'\ direction However, the saturation magnetic field is still high fuj^^ > 0,6 T [1] Studies carried out in the three-layer (sandwich) FelTerfecoHanlFe films have shown that for films in which the Fe-layer thickness (tfj ranges from nm to 20 nm, magnetic moments in the Fe-layers orient in the film plane whereas those in the TerfecoIIan-layers orient out of the film plane Such magnetic structure generates 90 ^-domain walls at interfaces This leads to the decreasing of saturation magnetic and promotes remarkably the rotation process of magnetic moments at low fields After annealing at temperature T^ < 250 X' (in order to release stress induced magnetostrictive susceptibility in the preparation), the Xxii ^ 2,5xlO'^T^ has been obtained in these Bdo cdo not nghi Vdt ly Chdt rdn Todn quoc Idn thit IV, Nui coc 5-7/11/2003 mOt each tu nhien Idp tiif mem sau chef tao bang each di^u khi^n nong d^ Y da tao vat lieu tiit giao co cac tmh chat lit mim va tiif giao tuySt vM: luc khang tuf nho pjir = 1,7 mT, tir giao cao A = 660x10^ va cam tir giao Inm xr = 15,3x10"^ T ' Cac vat lieu nghien ciiu rat kha quan cho trien khai irng dung LCII CAM O N Cdng trinh da duac tai tra boi de tai khoa hgc dac biet DHQG Ha noi QG 02.06 va de tai nghien ciiu khoa hgc ca ban 420.301 TAI LI$U THAM KHAO [1] J Betz, K Mackay and D Givord, J of Magn Magn Mater., 207 (1999) 180 [2] A Ludwig and E Quandt, Appl Phys 87 (2000) 4691 [3] N.H Due, in: Handbook of Physics and Chemistry of the Rare Earths, eds K.A.Gschneidner, Ir and L Eyring, Elsevier Science, North-Holland, Amsterdam, 2001,vol 32, p [4] N.H Due, se in trong: Tuyen tap Hgi nghi Vdt ly Chdt ran Idn thu A'', Nui CY)'c, 11/2003 [5] C L Chien, J Appl Phys., 69 (1991) 5267 [6] P Farber, H Kronmuller, J Appl Phys., 88 (2000) 2781 [7] N H Due, Magn Magn Mater., 242-245 (2002) 1411 [8] E Tremolet de Lacheisserise, D Gignoux, M Schlenker Magnetism Kluwer Academic Publisher, 2002, vol 2, p 227 * E-mail: man^dlh7mvahoo.cotn: Tel: (04) 8585281: Fax: (04) 8584438 BOd HUO nOl ngni Vdl lyi^natran loan quoc Idn thUIV, Nui coc 5-7/11/2003 M A G N E T O S T R I C T I V E M A T E R I A L S IN T H E T Y P E OF SPRING - M A G N E T S Terfecohan/YFeCo Do Thi Huong Giang*, Nguyen Huu Due, Vu Nguyen Thuc Faculty of Physics, College of Natural Science, Vietnam National Universty, Hanoi 334 Nguyen Trai, Thanh Xuan, Hanoi The sputtered {Terfecohan(12nm)/Yx(Feo7Coo3)j~x(10nm)} (0 < x < 0,2) multilayers were prepared and investigated hy means of tlie x-ray diffraction (XRD), magnetisation and magnetostriction measurements The results show thai in as-deposited multilayers the TbFeCo layers always remain in the amorphous state, whereas the microstructure of YFeCo layers varies strongly as a function of the Y-concentration: crystalline state is observed for FeCo layers, nanocjystalline structure is naturally fonned in Yo /(Fcn-Con i)o9 and, finally, amorphous phase is stabilised in Yo,2(Feo7Coo3)o8 individual layers This opens a novel approach to prepare the nanocrystalline state of YFeCo layers in (a- TerfecoHan/YFeCoj multilayers hy controlling the Y concentration In the {a-TerfecoHan/n-YFeCo}^n sample, a soft magnetic and magnetostrictive character with the coercivity /JoHr = 3.1 mT and the magnetostrictive susceptibility Xx = dX/d(i.ioH) = 3.5x10'^ T^ were already obtained The magnetic softness has been strongly improved hy heat treatments: ^iMc - 1-7 ^>^T and Xx = 15.3xW' T' This huge low-field magnetostrictive susceptibility is associated to the nanostructure of the YFeCo layers 'E-mail: ^iatmlthimyahoo.com: Tel: (04) 858528J: Fax: (04) R5844^8 ELSEVIER SCIENCE Natural nanostructure and magnetisation reversal process in TbFeCoA'x(FeCo)i.x spring-magnet type multilayers N.H Due'* D.T Huong Giang" and N Chau^ "Cryogenic Laboratory Center for Materials Science Faculty of Physics Vietnam Notional University Hanoi S.U Nguyen Trai Thanh Xuan Hanoi, lirtnnm Elsevier use only: Received date here; revised date here; accepted date here Abstract Studies of the natural nanostructure and magnetization reversal process are pcrrormcd for the sputtered 7b(Feo55Coo45)i 5^V,(Feo7Coo3)i.x multilayers (0 < x < 0.2) with a TbFeCo layer thickness /ibFcfo - 12 nm and VFeCn layer thickness /YFCCO = '0 ""i- The structural investigations show that nanocrystals are naturally formed and coexist within amorphous matrix in yoi(FeCo)og layers In this state, low magnetic coercivity and large parallel magnetostrictive susceptibility are observed The results are discussed in terms of the crystalline discontinuity of the soft VFcCo layers ''f 2001 Elsevier Science All rights reserved Keywords: Spring-exchange multilayers; Nanocrystalline structure; Magnetisation reversal; Giant magnetostriction; PACS: 75.60.Jk; 75.70.Cn; 81.07.Be; Introduction The exchange-spring concept [1] opened an alternative route towards new high-performance hard magnetic materials By associating a coercive hard magnetic phase with a large magnetization soft phase, it was expected that new high-energy product materials could be prepared Exchange-spring behavior was found in a various systems However, as far as our knowledge, no materials has been found with properties clearly superior to those of usual hard "magnetic materials Meanwhile, this concept has successfully been applied to the so-called giant magnetostrictive spring-exchange multilayers, uhcre high magnetostrictive layers and soft magnetic layers alternate [2] Indeed, Quandt and Ludwig [?>] obtained a magnetostriction as large as 90>^IO^' and a huge parallel fnagnctostrictive susceptibility (xv ^ (iAI(Sf{) of ^ 10 ' T ' '" an applied field of about a few tens militesla for magnetostrictive/soft magnetic TbFeCo^FeCo multilayers In this case, magnetization reversal is thought to be nucleated within the soft layer in low npplicd-ficld and propagates from the soft layers into the magnetostricti\e layers [4] In the TbFeCoTcCo multiln\crs, the soft FcC'olayer is continuous (fig la), thus the nuclcation of reversal occurs at some defect points on the sample surface and interfaces In this context, one expects that the reversal can be nucleated easier in discontinuous soft phase / e in layers in which the FeCo nanograins are embedded within a non-magnetic matrix (Tig lb) Practically, an excellent magnetic softness ha^ recently hecn reported for Tb(Feo 55C00 45)15''Vn 2^ l^Cn RCOO :)o R f denotes as Terfecohan/Yn:fFen9Cor.2)np multilayers, in which the nanostructure of YFcCo layers \\a^ rormcd from TT amorphous phase by heat treatments [5-'i] As far as our knowledge, the transformation of the amorphous state in the RCoFe (R ^ rare earths and'or light transition metals) layer is ^I0^ T ' This value is almost times higher than that of as-deposited.x = sample and is comparable to that of 350'^C-anncaIcd x = one The magnetostrictive softness, in particular, is strongly improved after annealing at 400°C: Zv/ reaches a maximal value of 14.5^10^ T ' at the magnetic field of I mT This X}j/ V alue i s a Imost t imes h igher t han t hat o btained i n Terfenol-D [13] and times higher than that obtained in multilayers by Quandt et al [2,3] Low-field magnetostriction A^ and />, data are presented in fig for the X = 0.2 films annealed at 450'C {i.e for the thermally induced nanostructured film) It turns out that the maximal Xx ^•aIue equals 15 ^ ' T ' This is in good accordance with the coerci\ity data that the excellent magnetic as ucll as magnetostrictnc softness can be obtained either in naturally or in thermally formed nanostr\Jctured multilayers Submitted to Elsevier Science '•• Concluding remarks For conclusion, it is worthwhile to mention that, in general, large X value is not obtained in conjunction with 'arge xvi- This is because magnetostriction is intimately associated to magnetocrystalline anisotropy and it is well known that the coercivity tends to be high in large anisotropy systems The obtained spectacular result illustrates the significance of the approach, which we have developed in view of optimizing both magnetostriction and magnetostrictive susceptibility in the spring-exchange magnet type multilayers with structural discontinuous soft layers Acknowledgements This work was granted by the Vietnam National University, Hanoi within the project QG.02.06 The authors acknowledge discussions with D Givord References -20 -18 -10 5 M,H (mT) 10 18 20 Fig Low-field magneto.striction (a) and parallel magnetostrictive susceptibility (b) data of Ihe as-deposited and 400*'C-annealed X = 0.1 multilayer [1] R Coehoom, D.B dc Mooij, J.P.W.B Duchleau and K H.J Buschow, J Phys (Paris) CoIIoq 49 (1988) C8-669; R Coehoom, D.B de Mooij and D de Waard, J Magn Magn Mat 88(1989) 101 [2] E Quandt, A Ludwig I Bet7 K Mackay D Oivnrd.J App Phys, 81 (1997)5420 |3] A Ludwig and E Quandt, J Appl Phys 87 (2000)4691 [4] N.H Due, D.T Huong Giang, V N Thuc N Chau and D Givord, in preparation [5] N.H Due, J Magn Magn Mater 242-245 (2002) 1411 [6] N H Due and P.E Brommer, in: Handbook of Magnetic I7J [8] [9] [10] [II) [12] Materials, ed K.H.J Buschow, (Elservier Science, NorthHolland, Amsterdam 2002) Vol 14, p 89 P Hansen, in: Handbook of Magnetic Materiah, cd K H J Buschow, Elsevier Science, Norlh-Holland Amsterdam,1991, vol p 289 U Herr, H Geisler, H Ippach and K Samwer, Phys, Rev B59(1999) 13719 N.H Due, K Mackay, J Betz and D Givord J Appl Phys, 79(1996)973 TM Danh N H Due H.N Thanh and J Teillet J Appl Phys., 87 (2000) 7208 N.H Due, D T Huong Giang V N Thuc NT Minh Hong, N Chau Physica B 327 (2003) 328 N I ! Duc.TM Dnnh, N A Tuan and J Teillet, Appl Pb> 0.6 0.4 0.2 0.0 r ^ : 0.00 0.05 0.10 0.15 0.20 BIT) Hinh 5: Dumg cong the dp dien liong ynng tu tmrng < B ^- 0.2 T Doi vdi mang ttr giao a-TerfecoHan co day tf = ^im da cho the ap dien kha \6n, U = 1420 mV tai B = 200 mT Ne^u sir dung vat lieu ttr giao Terfenol-D dang kho'i tf = 500 ^im thi tin hieu tang len 100 iSn: U = 3100 mV tai B = 10 mT (xem bang 2) Ket qua rat kha quan va cho phep xac dmh citctng cua cac tu tnrcmg tha'p: B = 0.1 mT irng vofi U = 29 mV TTTTjudc Idn thii IV, Niii Cdc 5-7/11/2003 B Bang 2: The dp dien cua hai cdu hinh sensa sii dung hai loqi vdt lieu tit gido mdng mong a-TerfecoHan vd mdu khdi Terfenol-D B(mT) U(mV) a-TerfecoHan Terfenol-D 200 1420 - 100 600 - 10 26 3100 355 0.1 29 IV K ^ T L U ^ N Mang mong ttr giao a-TerfecoHan da duoc sir dung de che" tao sensrt tir tnrcmg dua tren hieu ii'ng to hop tiif giao - ap dien Ciing vdfi qua trinh tren, chiing toi da thi^t ke va lap rap mach khuye'ch dai cong cu the ap dien cua senso Mot thiet bj hoan chinh bao gom mot senso ttr trucmg dua tren hieu ung ttr giao - ap dien va may rat gon nhe co nhay kha cao Do nhay cua senso hoan toan c6 the dieu khien duoc bang each thay ddi day Ic'yp ttr giao Trong tnrong hop sir dung cac mSu Terfenol-D dang khoi co day 500 |.im, nhay co the dat duoc 10' T Cong trinh da duac thifc hien nhd tai tra cm de tai khoa hoc dac hiel DHQG Ha ngi ma soKC 02.13.4 va de tai QG.02.06 TAI LifiU THAM KHAO [1] N H Due, T M Danh, II N Thanh, J Teilet and A Lienard .1 of Phys: Codcns, MaUer., 12(2000)8238 [2] N II Due, of Magn & Magn Mailer., 242 (2002), 1411 (3] A V Virkar, L Huang and R A Cutler, J Am Ceram Soc 70 (1987) 164 S E N S O R M E A S U R I N G M A G N E T I C F I E L D BASED ON PIEZO - MAGNETOSTRICTIVE EFFECT A piezo - magnetostrictive sensor is successfully manufactured with use of magnetostrictive film (prepared hy Oyogenic Laboratory) and a piezo material APC - 855 (supplied by American Piezoceramics Inc., PA, USA) In addition, a tool - amplifier is established The obtained piezo - magnetostrictive sensor shows a linear coefficient as large as 11 V/T in the magnetic field range up to 0.3 T By using giant wagnetostrictive films with good magnetic softness, sensor can he used to delect weak magnetic field (about several mT) or manufacture mine detector These results are promising for developing applications PHlfU DANG Kt K£T QUA NGHIEN CUU Ten de tai "Dieu khien cong nghe che'tqo va nghien citii cdc ca che ti( gido, tit tra, di huang ta vudng goc cdc mang mong Tetfecohan " Ma so: QG 02 - 06 Co quan chu tri de tai: Dqi hgc Khoa hpc Ti/nhien Dja chi: 334 Nguyin Trai, Thanh Xuan, Ha Ngi Tel: 5583001 Caquan quan ly de tai: Dqi hgc Quoc gia Ha Ngi Dia chi: 144 Xuan Thuy, Cdu Giay, Ha Ngi Tel: 7680978 Tong kinh phi thirc chi: 60 trieu dong Trong do: - Tir ngAn sach nha nm'yc: 60 trieu ddng - Kinh phi cua friroiig: trieu ddng - Vay tin dung: trieu ddng - Von tir co: trieu dong iq ?«: - Thu hoi: hieu ddng Thofi gian nghien turu: 18 thang Ihbi gian bdt ddu: 612002 Thdi gian ket thuc: 1212003 Ten cac can bo phoi hgp nghien curu NCS DS Thi Huang Giang Khoa Vdt ly, DHKHTN, DHQGHN CN Vu Nguyen Thiic Khoa Vat ly, DHKHTN, DHQGHN NCS Nguyin Thi Minh Hong Khoa Vat ly, DHKHTN, DHQGHN CN Nguyen Thanh Trung Khoa Vat ly, DHKITTN, DHQGHN GS.TSKH Nguyin Chdu Khoa Vat ly, DHKITTN, DHQGHN Khoa Vat ly, DHKHTN, DHQGHN TS.LeVdnVu ThS Chic Ditc Trinh Khoa Cdng nghe, DHQGHN CN.Vu Dice Hung Khoa Cdng nghe, DHQGHN S6 dang ky d^ tai S6' chirng nhan dang ky Ng^y: Ket qua nghien cuii: Bao mat: a Pho bie'n rong rai: b Pho bien han che: D c Bao mat: D Tom tat ket qua nghien cuu: / Da che tqo cdng cdc mang mong tic dua tren hcrji chat TerfercoHan: cdc mang dcm h'rp TetfecoHan, da lajy TeifccoHanlYfe, TeifecoHan/YFeCo vd Icfj) FelTeifecoHanlFe tren thiet bi phiin xq catot tqi Trung taw Khoa hoc \ 'at lieu, Khoa Vdt ly, Dqi hgc Khoa hgc Tu nhien, Dqi hgc Quoc gia Hd Ngi Cdc mang mdng TetfecoHan don lirp cd di huang tic vudng gdc Qud trinh tic hod cdc mdng motig Id qud trinh quay mdmen tic tic phuang vudng gdc vc'ri mat phang mdng sang phuang mat phang nuing Tie gido khong Id dqt dicqc vao cd 10^^ nhung bdo hod a tic trudiig cao {fifl > 0.6 T) 30 Fe (tpj ta nm din 20 nm, momen tic cua cdc lap Fe nam mat phdng mang nhung momen tu: cua cdc lop TerfecoHan lech khoi mat phang mang Cdu tnic tir nhu vay cho phep gid thiet su ton tai cua mot cdu true domen dgng 90''d cdc interfaces Do cung la nguyen nhdn lam gidm ti( tru&ng bdo hod va thiic day qud trinh quay xdy tqi tu: tru&ng thdp han vd tit gido phdt trien nhanh d tit tru&ng thdp Cdc mdu ba lap u a nhiet T^ 250 V, di hu&ng tit vuong goc Igi phdt trien mgnh tren cdc mdng mdng ba l&p Ngodi luc khdng tit vudng gdc cdn dgt duac t&i gid tri (fijic - 500 mT) Cdc thong sdndy thod mdn dieu kien img dung cho ghi tit vuong goc Ve mat vdt ly, ca che luc khdng tit vuong gdc cao dd dugc gidi thich bang su hinh cdu true nano l&p Fe & tren be mat (Ket qud ndy ddduac khdng dinh bdng cdc nghien cini dnh hien vi dien tu truyen qua) Cdc ddc trung tit - dien trd tren cdc mdng da l&p TerfecoHan/YFe vd TerfecoHanlYFeCo dd dugc khdo sdt Du&ng cong tit tri R(H) cd dgng gidng nhu du&ng cong tit gido /If/Yj, nhien, he sd tit - dien tra chi dgt cue dgi MR = 0,2% Ket qud ndy cho phep nhdn xet rang, cdu hinh tir vuong gdc cdc mdng mdng da l&p cd the dugc xem xet nhu Id cdu hinh cua dien trd l&ti Du&i tdc dung cua tH tru&ng ngodi, cdu triic tit doi thdnh song song v&i dien trd be Dd Id khd ndng tiem dn ciia mot cdu hinh tit - dien tra m&i Tuy nhien, cdc vat lieu dang xet, cdc dien tu4fcd linh dgng thdp, nen he sdtit - dien trd quan sdt dugc co gid tri be Cdc nghien citu cdc vdt lieu cd nong dd ddt hiem thdp han Id rdt cdn thiet de khdng dinh gid thiet dd Cdc nghien citu cdu trite vi md, tinh chdt tit, tit gido vd cache tir mem (rong cdc mdng mdng da l&p TerfecoHan/YFe vd TerfecoHan/YFeCo Id mot ket qud vum ngodi khuon kho dd ddng ki cua de tdi nhung cd y nghia rdt ddc biet Trong cdc nghien citu ndy, chiing toi dd tgo dugc trgng thdi nano tu nhien cdc l&p til mem ciia mdng mdng da l&[? TerfecoHan/YFe vd TerfecoHan/YFeCo 31 Do Id trgng thdi nano nhdn dugc khong cdn u nhiet md chi cdn dieu khien • thdnh phdn Y Day ciing la mot cdc tiep can m&i, mang dam y tuang Viet Nam Cdc vat lieu che tgo dugc cd tinh chdt tit vd tit gido sieu mem (/JOHC = A3 mT) vd cdm tit gido l&n Xxn = 29x10'^ T\ l&n gdp gdn 30 Idn so v&i gid tri ciia cdc vdt lieu Terfenol-D quen thugc Cdc ket qud dd dugc mo td dua tren cdu triic tinh the gidn doan cdc l&p Y(Fe,Co) Vat lieu tit gido che tgo dugc dd dugc su dung de che tgo sensa tit tru&ng dua tren hieu Ang tit gido - dp dien Cung v&i mot bo khuyech dgi dien tich tit che tgo, sensa tit gido dp dien co the sit dung de tit tru&ng Kien nghi ve quy mo va doi tuang ap dung nghien curu: Trien khai ket qud nghien citu cabdn sang nghien cuu itng dung v&i cdc dan vi Khoa Vdt ly - Tru&ng Dgi hgc Khoa hgc Tu nhien, Khoa Cong nghe - Dgi hgc Qudc gia Hd Ngi vd mot sd ca sa nghien cihi khdc Chu nhiem de tai Thu truang co quan chu th de tai Ho ten Nguyin Huu Diic Hoc ham PGS, TS hoc vi Ki ten Dong dau ,dM^ 70 Chii tich Hoi dong Thii truomg co quan danh gia chinh thuc quan ly de tai ... Magnetic films based on TerfecoHan compound consisting of single layer films, multilayer TerfecoHanlYFe TerfecoHan and TerfecoHanlYFeCo and three-layer (sandwich) FelTerfecoHanlFe films have... mdng mong TerfecoHan CAC Kl^T QUA DAT DirOC: 6.1 Ket qua nghien curu: Da che' tao cong cdc mang mong tit dua tren hop chat TerfercoHan: cdc mang dan l&p TerfecoHan, da l&p TerfecoHanlYFe, TerfecoHanlYFeCo... ciia cac mdng ba lap FelTerfecohanlFe sau ii d nhiet T^ = 450 TT 2.2.C, Mdng da lap TerfecoHonlY^Fcj.^ vd TerfecoHanlYJFeCo)^,^ Cac mang da Idp {Terfecohan/ Y^Fei.Jn va {TerfecoHan/ Y,(FeCo),.J^