ZnO, ,, Cr. PACS: Rs, Pp, Tt. (diluted magnetic semiconductor, DMS), , ZnCr 2 O 4. Liu [10]

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1 Cr ZnO * (,, ) ( ; ) ZnCl 2, CrCl 3 6H 2O, 4T Cr ZnO, X,. : Cr ZnO ZnO,, 4T Cr ZnO, (M s) emu/g,,, 16 K. :,,, Cr ZnO PACS: Rs, Pp, Tt 1 (diluted magnetic semiconductor, DMS),,, [1 3]. ZnO, 3.37 ev, 60 mev, ( GaN, ZnS ),,. 2000, Dietl [4] Sato [5], (transition metal, TM) ZnO DMS., ZnO [6 8]. Cr ZnO,. Schneider [9] Cr ZnO, Cr 6 at% 1000 C 5 K, ZnCr 2 O 4. Liu [10] Cr ZnO, Cr +3, 3 at%. Elanchezhiyan [11] Zn 1 x Cr x O(x = 0.05, 0.15, 0.30), Cr,, Cr (x = 0.15, 0.30) ZnCr 2 O 4. Hu [12] Cr Zn 1 x Cr x O (x < 0.073), Raman Cr 2 O 3, x Cr 2 O 3, (V Zn ), Cr 2.7 at%. Zhuge [13] Zn 1 x Cr x O, Satoh [14]. Chu [15] Cr ZnO, * ( : 09dz ), ( : 09YZ27), ( : S30107) ( : IRT0739). liying62@shu.edu.cn c 2012 Chinese Physical Society

2 , Cr 3 d O 2 p. Wang [16] Cr 2% ZnO, [17].. ZnO, ZnCl 2, NH 4 Cl, CrCl 3 6H 2 O, NH 3 H 2 O,., 2 mol/l 0.02 mol/l ZnCl 2 CrCl 3 6H 2 O,. Cr 1%. 6 ml ZnCl 2, 8ml, 6ml CrCl 3 6H 2 O, 1 h. 25 ml., 453 K, 4T, s 1, 30 s, 4 h.,., 343 K 8h., ; Cr 3+ ( ZnCl 2 ), ZnO,. 2.2 D/max-RC X (X-ray diffraction, XRD), Cu K α, 40 kv, 100 ma, λ nm. JSM-6700F (field emission scanning electron microscope, FESEM) EDS. LakeShore7407 (vibrating sample magnetometer, VSM). 3 1 ZnO Cr ZnO ( ZnO, S-4T S-0T) XRD. 1(a), S-0T S-4T ZnO(JCPDS, No ),, Cr, S-0T S-4T ZnO,,, Cr ZnO. 1(b) 2 θ XRD, ZnO, S-0T S-4T (100), (002), (101), S-4T S-0T. Cr 3+. Cr 3+ (0.63 Å) Zn 2+ (0.74 Å), Cr 3+ ZnO, Cr 3+. XRD, 1 XRD (a) (b)

3 Ô n Æ Acta Phys. Sin. Vol. 61, No. 7 (2012) ²óÀ^ e Cr3+ S,þ õ, L ²óÀ^ k ur? Cr3+ \ ZnO. ã 2 3kÃóÀ^ ^ ey9ü Cr, ZnO N SEM ãú EDS ãì. lã 2(a) Ú (b) ±wñ, S-0T òw 5K/m, Ì d Ñ G â, ²þ» nm, Ý nm, Ü kìày u ); S-4T K y²w 5K/m, dü ks Y)G, ²þ» nm, Ý 1 2 µm, B u \, Ãìà y u), "à²þ» nm. ' ã wñ, óà^ äkr? â ã2 ^, N âu ½ ). ù U du \^ 3 a, b, c UþØÓ B ) ÝØ [18], l 3 kóà^ B ) ÝwÍ \, 3Ù þ ) ÝÉ ½³, ª B Uì ½ ). óà^ e Cr, ZnO N ü K Ï Ùg äk^5, É^ ^u) =. â ã 2(c) Ú (d) S-0T Ú S-4T Cr S ¹ þ O 0.49%Ú 0.83%, ` ² ó À ^ J p Cr S, Y ², ù Ú XRD ( J. kãóà^ ^ ey9ü Cr, ZnO SEM ã ((a) S-0T; (b) S-4T) Ú EDS ãì; ((c) S-0T; (d) S-4T) «Cr, ZnO N ^5U(J. dã, óà^ e S-4T 3 (298 K) L y Ñ é Ð c ^ 5, Ù Ú ^ z r Ý (Ms ) emu/g; Ã^ e S-0T 3 evklyñc^5, ^^5. ã3 ^ ã ã 3 æ^ Ä ^ro3 eÿá ã 4 k à ó À ^ e Y 9 Ü Cr, ZnO N ^ 9 (M -T ), d d à ^ e S-0T Øp Ý (Tc ) 288 K, ó À^ e S-4T Tc 304 K. S-4T ' S-0T Øp Ýp 16 K, `²óÀ^ Ú\ Jp Cr, ZnO N Øp Ý, k u¼ c^5, ù K cï Ù AN

4 [19 21]., Cr 3+ ZnO, Cr O [15],. 0.5 T,.,,., Singhal [22], : M(H) = 2M s π tan 1 [ H Hc H c tan ( πs 2 ) ] + χh, (1) 4 (1), M s H c, S, S = M r /M s, χ. (1) S-0T 280 K (FM) (PM), 5, M s emu/g, S-4T M s emu/g., M s 2,. 4 5 S-0T 280 K 5 S-0T 280 K.., 1.3 T, emu/g, ;, 4T Cr ZnO. Cr 3+ Cr ZnO, 16 K.. [1] Wolf S A, Awschalom D D, Buhrman R A, Daughton J M, Molnár S von, Roukes M L, Chtchelkanova A Y, Treger D M 2001 Science [2] Matsumoto Y, Murakami M, Shono T, Hasegawa T, Fukumura T, Kawasaki M, Ahmet P, Chikyow T, Koshihara S, Koinuma H 2001 Science [3] Chiba D, Yamanouchi M, Matsukura F, Ohno H 2003 Science [4] Dietl T, Ohno H, Matsukura F, Cibert J, Ferrand D 2000 Science [5] Sato K, Katayama-Yoshida H 2001 Jpn. J. Appl. Phys. 40 L334 [6] Liu X C, Shi E W, Song L X, Zhang H W, Chen Z Z 2006 Acta Phys. Sin (in Chinese) [,,,, ] [7] Yang J J, Fang Q Q, Wang B M, Wang C P, Zhou J, Li Y, Liu Y M, Lü Q R 2007 Acta Phys. Sin (in Chinese) [,,,,,,, ] [8] Yu Z, Li X, Long X, Cheng X W, Wang J Y, Liu Y, Cao M S, Wang F C 2008 Acta Phys. Sin (in Chinese) [,,,,,,, ] [9] Schneider L, Zaitsev S V, Jin W, Kompch A, Winterer M, Acet M, Bacher G 2009 Nanotechnology [10] J, Liu X Y, Yang Y T, Wei M B 2009 J. Alloy. Compd [11] Elanchezhiyan J, Bhuvana K P, Gopalakrishnan N, Shin B C, Lee W J, Balasubramanian T 2009 J. Alloy. Compd

5 [12] Hu Y M, Hsu C W, Wang C Y, Lee S S, Wang S J, Han T C, Chou W Y 2009 Scripta Mater [13] Zhuge L J, Wu X M, Wu Z F, Chen X M, Meng Y D 2009 Scripta Mater [14] Satoh I, Kobayashi T 2003 Appl. Surf. Sci [15] Chu D W, Zeng Y P, Jiang D L 2007 Solid State Commun [16] Wang B Q, Iqbal J, Shan X D, Huang G W, Fu H G, Yu R H, Yu D P 2009 Mater. Chem. Phys [17] Miao H Y, Li H Q, Tan G Q, An B J, Wei Y X 2008 J. Inorg. Mater (in Chinese) [,,,, ] [18] Chu D W, Zeng Y P, Jiang D L 2007 J. Phys. Chem. C [19] Li Y B, Li Y, Zhu M Y, Yang T, Huang J, Jin H M, Hu Y M 2010 Solid State Commun [20] Huang J, Zhu M Y, Li Y, Yang T, Li Y B, Jin H M, Hu Y M 2010 J. Nanosci. Nanotechno [21] Yang T, Li Y, Zhu M Y, Li Y B, Huang J, Jin H M, Hu Y M 2010 Mater. Sci. Eng. B [22] Singhal R K, Dhawan M S, Gaur S K, Dolia S N, Kumar S, Shripathi T, Deshpande U P, Xing Y T, Saitovitch E, Garg K B 2009 J. Alloy. Compd Synthesis of Cr-doped ZnO diluted magnetic semiconductor by hydrothermal method under pulsed magnetic field Zhu Ming-Yuan Liu Cong Bo Wei-Qiang Shu Jia-Wu Hu Ye-Min Jin Hong-Ming Wang Shi-Wei Li Ying ( Laboratory for Microstructures/School of Materials Science and Engineering, Shanghai University, Shanghai , China ) ( Received 4 June 2011; revised manuscript received 24 August 2011 ) Abstract In this study, zinc chloride, chromic chloride, ammonium hydroxide and ammonium chloride are used as the source materials to prepare the crystalline Cr-doped ZnO diluted magnetic semiconductor by the hydrothermal method under a 4-T pulsed magnetic field. The structures and the morphologies of the samples are characterized by X-ray diffraction and scanning electron microscope. The magnetic analysis of the specimens is performed by vibrating sample magnetometer. The effects of pulsed magnetic field on the microstructure and the magnetic properties of the Cr-doped ZnO are discussed. The result indicates that all the samples still have hexagonal wurtzite structures. The pulsed magnetic field is conducive to promote the crystal growth orientation. The sample fabricated under pulsed magnetic field exhibits good room temperature ferromagnetism. The saturation magnetization is emu/g. However, the sample synthesized without magnetic field shows paramagnetism at room temperature. The Curie temperature (T c) of the Cr-doped ZnO is increased by 16 K through the pulsed magnetic field processing. Keywords: pulsed magnetic field, hydrothermal, Cr-doped ZnO, diluted magnetic semiconductor PACS: Rs, Pp, Tt * Project supported by the Shanghai Science and Technology Commission (Grant No. 09dz ), the Shanghai Education Commissions (Grant No. 09YZ27), the Shanghai Leading Academic Discipline Project (Grant No. S30107), the Changjiang Scholars and Innovative Research Team in University (Grant No. IRT0739). liying62@shu.edu.cn