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1 Journal of the Korean Magnetics Society, Volume 19, Number 5, October 2009 DOI: /JKMS Cd 1 x Mn x» Ÿw p y zá yá w w, û 29, ( , , y ) Bridgman Cd 1 x Mn x g Mn y»ÿw p w. X- z x l x < 0.82 w zinc-blende y w. Mn ƒ w x ƒw. Faraday z Ÿ ƒ ƒw š, Mn xƒ ƒw ƒw. Cd 0.62 w Ÿ p db. :, Bridgman, CdMn, q z, Ÿ p I. yw Mn, Fe Co y Eu Gd m ey k (semimagnetic semiconductor: SMSC y diluted magnetic semiconductor: DMS) w, 1979 Galazka w Cd 1 xmn x»- Ÿw š z II 1 xmn x VI w x, ƒ ¾ y w š [1-3]. SMSC ey ƒ š y y» w,» w 3d s-x y p-x ƒ v- v y y sp-d y y ƒ y š» wz k [4-6]. w z g- Zeeman ƒ f j Faraday z z ƒ ùkù [4]. Faraday z Ÿw rÿ Ÿ m jš, w w sww» ƒw Ÿ rÿ z w x [7-9] z w» Ÿ isolator, Ÿ e»ÿw ƒ š š [10, 11]. w, SMCS Faraday z jš, (nonmagnetic) II-VI yw z w, d v (band) v y y y w [12]. x ¾ Faraday y š As 2 S 2, *l: (052) , younghh@ulsan.ac.kr ZnSe, Bi 12 SiO 20 (BSO), FR-5 glass, Y 3 Fe 5 O 12 (Yttrium Iron Garnet, YIG) [13]. p, Cd 1 xmn x ƒ Ÿ ZnSe Faraday z z ƒ f,»ÿw y w» w w ƒ w š [14-16]. Cd Mn ey k Cd 1 xmn x Mn ƒ 0.0 x 0.82 zincblende ƒ, Mn ƒ w w, ƒw.» y, x <0.2 (paramagnetic), 0.2 x 0.65 v (spin glass), š x > 0.65 (antiferromagnetic) w [1]. Faraday y w» w» š v Cd 1 xmn x Bridgman g,, Ÿw,» p w š,»ÿw p w Ÿ isolator ƒ w y wš w. II. x Cd 1 xmn x Cd(5 N), Mn(4 N), (6 N) 5%-HNO 3 5%-HCl yv w z 1 x : x :1 mole yww k gqw x ~10 torr w œ w g 6 p w w 2», Bridgman [17] g. x X- z (X-ray diffraction) EPMA(electron probe microanalysis) x l w. y Ÿ UV-visible spectrometer 200~1200 nm d w,» p SQUID(Superconducting 186

2 Cd 1 x Mn x» Ÿw p y zá yá 187 Quantum Interference Device, Quantum design) w w.»ÿw p 9 mm, Ì 3mm w 0.05 µm ù» w k, m, š q w z Faraday z x ww. III. š θ-2θ XRD d l Cd 1 xmn x zincblende y w š[17], y Mn ƒ ƒw ƒ w. ƒ w Mn œ w (1.326 Å) Cd(1.405 Å)» ƒ ƒw w ƒ. Fig. 1 Cd 1 xmn x x y Ÿ rp š. α = O.D./d š,» O.D. optical density, d Ì. Ì d O.D. photon energy(hν) w 2 (α hν) (hν) w, w [18]. ƒ ƒw Fig. 2. The Verdet dispersion curves at 300 K for CdMn with Mn concentrations up to x = The various kinds of points are experimental data, and the solid lines are the best fits using the singleoscillator model. ƒw. ƒ w» q. wr ƒ -s y q z w ƒ ƒw w [19]. Fig. 2 Mn q y Verdet Fig. 1. Typical absorption spectra corresponding to samples with high and low Mn contents measured in the temperature range from 12 K to 300 K to 10 K intervals.

3 188 š. Faraday z ƒ θ F = VBl x.» V Verdet, ¼ (cm)» (G) w z ùküš w B»», l Ì. z ƒ y» w ww Ÿ w rÿ z w (+) w. x =0.0 Verdet ƒ, x > 0 ƒ. (nonmagnetic) Cd Mn ƒ» y w [5]. w Verdet q w ƒw ƒ. w Mn 2+ d v (conduction band)ù ƒ (valence band) v w v y y w». Fig. 2 (single-oscillator model) w (1) l (fitting)w ùkü [20]. ( ) = D E 0 ( 1 y 2 ) 3/2 V E y 2 F 0l» D D = M β α š M M = χb 2hc g Mn µ B ùkü, y =(E/E 0 ), χ» š, B»». l w E 0 D Mn x = 0.0, 0.11, 0.21, 0.4, 0.52, 0.65 w ƒƒ E 0 = 1.506, 1.738, 1.872, 2.059, 2.326, ev, D = 0.052, 15.69, 21.52, 35.45, 44.06, degá 3 ev/cm ƒwš. xƒ ƒw E 0 ƒ (absorption edge) q w, D ƒ (1) (1) w»wz 19«5y, Fig. 3. The Faraday rotations as a function of magnetic field of Cd 1 x Mn x with various Mn concentrations near the fundamental band gap at 300 K.» (magnetic susceptibility) Cd 1 xmn x Mn ƒ ƒw» f» [12]. Fig. 3 Cd 1 xmn x q š jš,»» Ì Faraday z š. Cd z y w w (+) š, Cd 1 xmn x ( ) ùkû, Mn ƒ ƒw z x =0.38¾ ƒ w ƒ, z wš.»» z ƒ z ƒ x w, w»» ƒ Verdet ùkü. Fig. 3 l w Verdet x = Fig. 4. Schematic diagram of optical isolator using a Cd 1 x Mn x single crystal in 0.4 T magnetic field.

4 Cd 1 x Mn x» Ÿw p y zá yá , 0.11, 0.21, 0.38, 0.52, 0.65 w 0.03(850 nm), 0.175(775 nm), 0.204(715 nm), 0.344(650 nm), (600 nm), 0.150(585 nm) deg/cm G.» 650 nm Ÿ w x = 0.38 Verdet ƒ j ƒ Ÿ ZnO(0.018, 404 nm), ZnSe(0.004, 463 nm), CdS(0.018, 536 nm), Hoya glass(0.0042, nm), GaAs(0.005, 777 nm) { f Ÿ isolator y ƒ w q w [13]. Fig. 4 Cd 0.62 w Ÿ isolator ùkü. Ÿ isolator w ƒ š, w w w Ÿ ( ), ww w Ÿ š ( w ) p ƒ w, Ÿ w n j Ÿ t ¼ Ÿ, Ÿ s» Ÿ t ƒ w w w. Ÿ p p (insertion loss) (isolation) ùkü. w Ÿ»(P 1 ) Ÿ»(P 2 ) w decibel(db) ùkü., = 10log[P 2 /P 1 ]. w Ÿ»(P4) Ÿ»(P3) w., (db) = 10log[P 4 /P 3 ]. 0.5 db ƒ w w Cd db. w, Cd db Ÿ l ƒ w p, š Ÿm 60 db [21], Ÿ Ÿ l w 40 db š w [22, 23]. wr, w Ÿ isolator» w 45 o - Faraday ƒ v w, Cd 1 xmn x ¼»» y j o 45 z ƒ w w. IV. Cd 1 xmn x Ÿ isolator y w» w Faraday z d w. 1. Bridgman k Cd 1 xmn x Mn ƒ 0 x 0.82 X- z x l zinc-blende y w š, w dw. 2. Ÿ d l x w ƒw š, ƒ w w. 3. Cd 1 xmn x Faraday z, Cd Verdet, x >0 ùkû. 4. Cd 1 xmn x Faraday z Ÿ ƒ w š, Mn ƒ ƒw ƒw ƒ x >0.4 w. 5. Cd 1 xmn x» y Faraday z x w» d w ZnSe w y w. 6. Ÿ isolator» w 45 o -Faraday ƒ v w, w Cd 1 xmn x ¼» y j o 45 z ƒ w w. w w ƒ (Grant # ) 2009 ( w» ) w w w ( ). š x [1] R. R. Galazka, S. Nagata, and P. H. Keesom, Phys. Rev. B, 22, 3344 (1980). [2] J. K. Furdyna, J. Appl. Phys., 53, 7637 (1982). [3] J. A. Gaj, R. R. Galazka, and M. Nawrocki, Solid State Commun., 25, 193 (1978). [4] B. B. Krichevtsov, R. V. Pisarev, A. A. Rzhevskil, and V. N. Gridnev, JEPT Lett., 67, 602 (1998). [5] L. Bryja, M. Ciorga, J. Misiewicz, A. Zaleski, P. Becla, and W. C. Chou, J. Cryst. Growth, 197, 694 (1997). [6] W. E. Hagston, T. Stirner, and J. Miao, J. Appl. Phys., 82, 5635 (1997). [7] S. Nudelman and S. S. Mitra, Optical Properties of Solid (Plenum press, New York, 1998). [8] A. Tsuzuki, H. Uchida, H. Takagi, P. B. Lim, and M. Inoue, J. Magnetics, 11, 143 (2006). [9] J. K. Cho, J. Magnetics, 12, 156 (2007). [10] E. Oh, A. K. Ramdas, and J. K. Furdyna, J. Lumin., 52, 183 (1992). [11] A. E. Turner, R. L. Gunshor, and S. Datta, Appl. Optics, 22, 3152 (1983). [12] S. V. Melnichuk, A. I. Savchuk, and D. N. Trifonenko, Phys. Solid State, 38, 731 (1996). [13] J. J. Dubowski, K. Lebecki, and M. Buchanan, IEEE Transac-

5 190 w»wz 19«5y, tion on Instrument on Measurements, 42, 332 (1994). [14] A. Ebina, T. Koda, and S. Shionoya, J. Phys. Chem. Solids, 26, 1497 (1965). [15] J. J. Dubowski, K. Lebecki, and M. Buchanan, IEEE Transactions on Instrument on Measurements, 42, 332 (1994). [16] E. Muller and W. Gebhardt, IEEE Transactions on Magnetics, 29, 82 (1993). [17] Y. H. Hwang, H. K. Kim, S. Cho, Y. H. Um, and H. Y. Park, J. Crystal Growth, 249, 391 (2003). [18] T. Koyanagi and K. Matsubara, J. Appl. Phys., 61, 3020 (1987). [19] V. Heine and J. A. Van Vechten, Phys. Rev. B, 13, 1622 (1976). [20] D. U. Bartholomew, J. K. Furdyna, and A. K. Ramdas, Phys. Rev. B, 34, 6943 (1986). [21] G. Lutes. Apply. Opt., 27, 1326 (1988). [22] T. Tamki and N. Kawamura, J. Appl. Phys., 70, 4581 (1991). [23] M. shirasaki and K. Asama, Apply. Opt., 21, 4296 (1982). A Study on the Magneto-optical Properties and Application of Diluted Magnetic Semiconductor Cd 1 xmn x Younghun Hwang, Youngho Um, and Sunglae Cho Department of Physics, University of Ulsan, Ulsan , Republic of Korea (Received 23 July 2009, Received in final form 28 September 2009, Accepted 30 September 2009) We investigated the magneto-optical properties and application of diluted magnetic semiconductors Cd 1 x Mn x crystals with various Mn contents grown using a vertical Bridgman method. This material crystallizes in the zinc-blende structure for values of x < The band-gap energy was depended on Mn mole fraction x linearly and increased with decreasing temperature. The Faraday rotation was increased as the photon energy increased near to that of the fundamental band gap and its increased with increasing Mn mole fraction. Optical isolator using the Cd 0.62 crystal shows that the isolation and insertion loss are 45 db and 0.35 db at 650 nm, respectively. Keywords : diluted magnetic semiconductor, vertical bridgman method, CdMn, faraday rotation, optical isolator