Magnetic and transport properties of La₀.₈Sr₀.₂MnO₃/La₀.₈Ca₀.₂MnO₃ bilayer

The effects of lattice strain on the magnetic and the transport properties of La₀.₈Sr₀.₂MnO₃ films grown on an (001) LaAlO₃ substrate and on a La₀.₈Ca₀.₂MnO₃ layer were studied. It was observed that the metal-insulator and the ferromagnetic transitions occur at higher temperatures for the film depos...

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Published in:Физика низких температур
Date:2003
Main Authors: Prokhorov, V.G., Kaminsky, G.G., Komashko, V.A., Lee, J.S., Park, Y.P.
Format: Article
Language:English
Published: Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України 2003
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Online Access:https://nasplib.isofts.kiev.ua/handle/123456789/128902
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Cite this:Magnetic and transport properties of La₀.₈Sr₀.₂MnO₃/La₀.₈Ca₀.₂MnO₃ bilayer / V.G. Prokhorov, G.G. Kaminsky, V.A. Komashko, Y.P. Lee J.S. Park // Физика низких температур. — 2003. — Т. 29, № 8. — С. 885-888. — Бібліогр.: 12 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
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author Prokhorov, V.G.
Kaminsky, G.G.
Komashko, V.A.
Lee, J.S.
Park, Y.P.
author_facet Prokhorov, V.G.
Kaminsky, G.G.
Komashko, V.A.
Lee, J.S.
Park, Y.P.
citation_txt Magnetic and transport properties of La₀.₈Sr₀.₂MnO₃/La₀.₈Ca₀.₂MnO₃ bilayer / V.G. Prokhorov, G.G. Kaminsky, V.A. Komashko, Y.P. Lee J.S. Park // Физика низких температур. — 2003. — Т. 29, № 8. — С. 885-888. — Бібліогр.: 12 назв. — англ.
collection DSpace DC
container_title Физика низких температур
description The effects of lattice strain on the magnetic and the transport properties of La₀.₈Sr₀.₂MnO₃ films grown on an (001) LaAlO₃ substrate and on a La₀.₈Ca₀.₂MnO₃ layer were studied. It was observed that the metal-insulator and the ferromagnetic transitions occur at higher temperatures for the film deposited on La₀.₈Ca₀.₂MnO₃ layer than on LaAlO₃. The dependence of Curie temperature on the bulk and the Jahn-Teller strains were also determined.
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fulltext Fizika Nizkikh Temperatur, 2003, v. 29, No. 8, p. 885–888 Magnetic and transport properties of La Sr MnO0.8 0.2 3/La Ca MnO0.8 0.2 3 bilayer V.G. Prokhorov, G.G. Kaminsky, and V.A. Komashko Institute of Metal Physics of the National Academy of Sciences of Ukraine, 36 Vernadsky bul’var, Kiev, 03142, Ukraine E-mail: pvg@imp.kiev.ua Y.P. Lee and J.S. Park Quantum Photonic Science Research Center and Department of Physics, Hanyang University, Seoul, 133–791 Korea Received January 21, 2003 The effects of lattice strain on the magnetic and the transport properties of La Sr MnO0.8 0.2 3 films grown on an (001) LaAlO3 substrate and on a La Ca MnO0.8 0.2 3 layer were studied. It was ob- served that the metal-insulator and the ferromagnetic transitions occur at higher temperatures for the film deposited on La Ca MnO0.8 0.2 3 layer than on LaAlO3 . The dependence of Curie temperature on the bulk and the Jahn—Teller strains were also determined. PACS: 71.30.+h, 75.70.–i Doped colossal-magnetoresistance (CMR) manga- nite perovskites exhibit a strong correlation between their lattice structure and magneto-transport proper- ties [1]. This phenomenon becomes apparent in thin films. The lattice strain (and stress) accumulated dur- ing epitaxial growth of a film plays an important role in the formation of the spin- and the charge-ordered states, the metal-insulator transition temperature, and the value of magnetoresistance [2–4]. The effect of the kind of single-crystal substrate on the magnetic and the electronic properties of man- ganite films has been investigated well [5,6]. On the other hand, to develop hybrid devices based on multi- layered CMR films detailed information on the mu- tual influence between constituent layers is required. It is expected that the magnetic and the transport properties of a multilayer structure can substantial- ly differ from those of the individual films of the constituent layers. In this work we report experi- mental results for La Sr MnO0.8 0.2 3 (LSM) and La Ca MnO0.8 0.2 3 (LCM) films and for a La Sr MnO0.8 0.2 3/La Ca MnO0.8 0.2 3 bilayer (BL). All films were prepared by rf magnetron sputtering using a so-called «soft» (or powder) target [7]. The total pressure in the chamber was 5 10 2� � Torr with a 3:1 Ar–O2 gas mixture. The substrate was a LaAlO3 (001) single crystal (LAO) with an out-of-plane lat- tice parameter c � 0.379 nm for pseudocubic symmetry. The substrate temperature during deposi- tion was 750�C. Both LSM and LCM films were de- posited with a thickness d � 60 nm, and the BL was deposited with the same thickness for each layer and with LSM on top. The �–2� x-ray diffraction (XRD) patterns were obtained using a Rigaku diffractometer and CuK� radiation. The lattice parameters evaluated directly from the XRD data were plotted against cos sin2 � �/ . A more precise determination of the lat- tice parameter was obtained extrapolating a straight line to cos sin2 0� �/ � . The resistance measurements were carried out using the four-probe method in the temperature range of 4.2–300 K and a magnetic fields up to 5 T. The magnetization in a field up to 100 Oe and the susceptibility at 500 Hz were obtained with a Quantum Design SQUID magnetometer in the tem- perature range of 4.2–300 K. Figure 1,a presents the �–2� XRD scans for LSM (curve 1), LCM (curve 2) and BL (curve 3) films. The high intensities of the (00l) peaks show that the deposition results in highly c-oriented films. Figu- re 1,b shows that the location of the (002) Bragg peak for the BL is almost coincident with that for the LCM film. In contrast, the peak for the LSM film is dis- © V.G. Prokhorov, G.G. Kaminsky, V.A. Komashko, Y.P. Lee, and J.S. Park, 2003 tinctly shifted to a smaller angle. Therefore the analy- sis of XRD data reveals that the out-of-plane lattice parameter for the LSM film is strongly dependent on the substrate: c� 0.398 nm on the LAO substrate and c � 0.391 nm on the La Ca MnO0.8 0.2 3 film with lat- tice parameter c � 0.3905 nm. Figure 2,a displays the temperature dependence of the resistance R for LSM (curve 1), LCM (curve 2) and BL (curve 3) films without (filled circles) and with (open circles) an applied magnetic field of 5 T. The magnetic field was directed at right angle to both the film surface and the transport current. The experi- mental curves show that the metal–insulator (MI) transition temperatures for both LSM and LCM films are very close, about 230 K. The BL film undergoes a MI transition at 280 K, which is higher than for the individual films. The MI transition temperatures for all samples are indicated by arrows. The inset in Fig. 2,a shows that the R(T) behavior of the BL film differs from that predicted by the simple two paral- lel-resistor model (solid line), where the first resistor corresponds to the LSM film (curve 1) and the second one to the LCM film (curve 2). Since the lattice pa- rameter c changes significantly only for the LSM film deposited on the LCM layer, it is reasonable to inter that the increase in the MI transition temperature for BL is due to the improved magnetic and electronic properties of the LSM film only. Figure 2,b presents the temperature-dependent mag- netoresistance, MR(%) [ ( ) ( )] ( )� �R R H /R H0 100 , obtained for LSM (curve 1), LCM (curve 2) and BL (curve 3) film in an applied magnetic field of 5 T. Here, R( )0 and R H( ) are the resistances without and with a magnetic field. It is seen that a slight enhance- ment in the MR for BL, with respect to the individual LSM and LCM films, is observed only at high tempe- ratures. In the low-temperature range the MR of BL remains smaller than that of the LSM film and mimics the MR(T) behavior for the LCM film. Figure 3,a shows both field-cooled (FC) and ze- ro-field-cooled (ZFC) temperature-dependent magne- tization curves for LSM (curve 1), LCM (curve 2) and BL (curve 3) films. The arrows show the corre- sponding Curie temperatures. The LCM film mani- 886 Fizika Nizkikh Temperatur, 2003, v. 29, No. 8 V.G. Prokhorov, G.G. Kaminsky, V.A. Komashko, Y.P. Lee, and J.S. Park 3 2 2 31 1 0 45 46 47 48 2 � , deg In te n si ty , 1 0 cp s 4 In te n si ty , c p s (002) LA O b 2 � , deg 20 40 60 80 10 10 F FSF S (0 01 ) (0 0 2 ) (0 0 3 ) S 1 2 3 a 10 10 2 3 4 5 Fig. 1. �–2� XRD patterns of LSM (1), LCM (2) and BL (3) films (a). The (002) XRD peaks (b). 1.0 0.5 200 300 5 4 3 2 1 BL B L ca lc T, K R , 1 02 W R e si st a n ce , 1 0 � 3 LCM LSM 1 1 2 2 3 3 BL a 10 10 10 1 2 3 1 2 3 b M a g n e to re si st a n ce , % 100 200 300 T, K 0 0 Fig. 2. Temperature dependence of the resistance for LSM (1), LCM (2) and BL (3) films without (filled circles) and with (open circles) an applied magnetic field of 5 T. The lines are visual aids. Inset: The experimental (circles) and computed (solid line) dependences R T( ) for the BL film. The arrows show the MI transition temperatures for different samples (a). Temperature dependence of the mag- netoresistance for LSM (1), LCM (2) and BL (3) films. The lines are visual aids (b). fests a sharp transition to the ferromagnetic state at TC � 230 K, in agreement with the published results for as-grown films [3]. In contrast, the LSM film displays a broad and smooth magnetic transition near TC � 260 K. Moreover, the absolute value of the satu- rated FC magnetization is half of that for the LCM film of similar thickness. The same behavior of M T( ) and a lower value of TC with respect to the bulk value have been observed previously for a La Sr MnO0.67 0.33 3 film deposited on a LAO substrate [8,9]. It was explained by the 3-dimensional strain states in the film, governed by the epitaxial mode of film growth. The temperature-dependent magnetiza- tion for BL is significantly different from that pre- dicted by simply adding the M T( ) values for both individual LSM and LCM films. The dashed line in Fig. 3,a shows the predicted curve: M TBL( ) � � �M T M TLCM LSM( ) ( ), where M TLCM( ) and M TLSM( ) are the magnetizations for the LCM and the LSM films, respectively. Since the thicknesses of the individual films are similar to those of the corre- sponding layers in BL, the added curve fits the experi- mental data fourty well at low temperatures (in the saturation magnetization range). However, the ferro- magnetic transition of the BL film occurs at a higher temperature (TC � 280 K) than predicted. This result confirms that a significant change occurs in the mag- netic properties of the LSM film deposited on LCM with respect to that on LAO. This conclusion is supported by the temperature dependences of susceptibility for LSM (curve 1), LCM (curve 2) and BL (curve 3) films in Fig. 3,b. Since the low-temperature susceptibility peak for BL (curve 3) mimics that of the individual LCM film, it can be concluded that the second peak belongs to the LSM layer in the BL. It is evident that the magnetic transition of the LSM film deposited on LCM becomes sharper and the saturated magnetization is achieved at a higher temperature than for a bare LSM film (see curve 1). Let us consider the possible mechanisms of en- hanced magnetic and transport properties of the LSM film on LCM with respect to that on LAO. The afore- mentioned analysis of x-ray data showed that the out-of-plane lattice parameter c is larger for LSM/LAO. It is well known that LSM thin films grown on LAO substrates exhibit an out-of-plane uniaxial tensile strain and, correspondingly, an in-plane biaxial com- pression [9,10]. Assuming that the film is strained from the ideal bulk structure and that the structure is a single perovskite, the in-plane lattice parameter of film can be estimated from the unit cell volume in the bulk. The bulk La Sr MnO0.8 0.2 3 compound has a rhombohedral pseudocubic symmetry (R c3 ) with hexagonal lattice parameters of ah � 0.5517 nm and ch � 1.3359 nm [11]. They are equivalent to cubic lat- tice parameters of a� b � c � 0.3871 nm and to unit cell volume V � 0.058 nm3. Therefore, the in-plane lattice parameter for our LSM/LAO is V/c� a � � 0.3828 nm, which is almost identical to the value obtained for an epitaxial La Sr MnO0.67 0.33 3 thin film [1]. For our LSM/LCM the in-plane lattice parame- ter is larger and equals a� 0.3852 nm. This difference between film and bulk lattice parameters leads to the formation of the above-mentioned in-plane biaxial Magnetic and transport properties of La Sr MnO08 0.2 3/La Ca MnO0.8 0.2 3 bilayer Fizika Nizkikh Temperatur, 2003, v. 29, No. 8 887 4 4 3 3 2 2 1 1 0 0 50 100 150 a LC M LS M FC ZFC B L 1 1 2 1 2 2 3 3 3 M a g n e tiz a tio n , 1 0 e m u 4 200 250 300 T, K b S u sc e p tib ili ty , 1 0 e m u 6 5 Fig. 3. Temperature dependence of the FC and the ZFC magnetization for LSM (1), LCM (2) and BL (3) films. The lines are visual aids. The arrows indicate the magnetic transition temperatures for different samples. The dashed line was obtained by simple addition of the FC M T( ) cur- ves (1) and (2) (a). Temperature dependence of the sus- ceptibility for LSM (1), LCM (2) and BL (3) films. The lines are visual aids (b). compressive strain, 100 � �( )a a /afilm bulk bulk , and the out-of-plane uniaxial tensile strain, 001 � �(cfilm � c /cbulk bulk) . The calculations performed show that 100 � –1.37% and 001 � 2.8 % for the LSM/LAO and –0.49% and 1%, respectively, for the LSM/LCM. For weaker strains and cubic symmetry the Curie point can be expressed as, according to Millis model [12], T TC C B JT( ) ( ) � � � � � � � � �0 1 1 2 2� , where B � �( )2 100 001 is the bulk strain, JT � � �2 3 001 100/ ( ) is the Jahn—Teller strain, � � � ( )( )1/T dT /dC C B , and � � ( )( )1 2 2/T d T /dC C JT . For the last two quantities we are took the values from Ref. 12, i.e. � � 10 and � � 1000. Using this equation and the values obtained for 100 and 001 in our LSM film and layer we calculated the change in Curie temperature T /T C C/ /LSM LCM LSM LAO calc calc � 1.07, which is an excellent agreement with our experimen- tal result T /TC C/ /LSM LCM LSM LAO � 1.077. This con- firms the strong correlation between crystal lattice distortion and the electronic and magnetic states in CMR materials. In summary, the magnetic and the transport pro- perties of La Sr MnO0.8 0.2 3 films grown on an (001) LaAlO3 substrate and on a La Ca MnO0.8 0.2 3 layer were studied. It was shown that the metal-insulator and the ferromagnetic transitions occur at higher tem- peratures for the film deposited on La Ca MnO0.8 0.2 3 layer than on LaAlO3 . The enhanced magne- toresistance and ferromagnetic ordering in the La Sr MnO0.8 0.2 3/La Ca MnO0.8 0.2 3 bilayer can be explained by lattice strain relaxation in the La Sr MnO0.8 0.2 3 film. This work was funded by the KOSEF through the Quantum Photonic Science Research Center. 1. F. Tsui, M.C. Smoak, T.K. Nath, and C. B. Eom, Appl. Phys. Lett. 76, 2421 (2000). 2. R.A. Rao, D. Lavric, T.K. Nath, C.B. Eom, L. Wu, and F. Tsui, Appl. Phys. Lett. 73, 3294 (1998). 3. S. Jacob, T. Roch, F.S. Razavi, G.M. Gross, and H.-U. Habermeier, J. Appl. Phys. 91, 2232 (2002). 4. A. Biswas, M. Rajeswari, R.C. Srivastava, T. Venka- tesan, R.L. Green, Q. Lu, A.L. de Lozanne, and A.J. Millis, Phys. Rev. B63, 184424 (2001). 5. O.I. Lebedev, G. Van Tendeloo, S. Amelinckx, H.L. Ju, and K.M. Krishnan, Philos. Mag. 80, 673 (2000). 6. J.R. Sun, C.F. Yeung, K. Zhou, L.Z. Zhou, C.H. Leung, H.K. Wong, and B.G. Shen, Appl. Phys. Lett. 76, 1164 (2000). 7. V.G. Prokhorov, G.G. Kaminsky, V.A. Komashko, J.S. Park, and Y.P. Lee, J. Appl. Phys. 90, 1055 (2001). 8. T.K. Nath, R.A. Rao, D. Lavric, C.B. Eom, L. Wu, and F. Tsui, Appl. Phys. Lett. 74, 1615 (1999). 9. A.M. Haghiri-Gosnet, J. Wolfman, B. Mercey, Ch. Si- mon, P. Lecoeur, M. Korzenski, M. Hervieu, R. Des- feux, and G. Baldinozzi, J. Appl. Phys. 88, 4257 (2000). 10. Y.H. Li, K.A. Thomas, P.S.I.P.N. de Silva, L.F. Cohen, A. Goyal, M. Rajeswari, N.D. Mathur, M.G. Blamire, J.E. Evetts, T. Venkatesan, and J.L. MacManus-Driscoll, J. Mater. Res. 13, 2161 (1998). 11. J.F. Mitchell, D.N. Argyriou, C.D. Potter, D.G. Hinks, J.D. Jorgensen, and S.D. Bader, Phys. Rev. B54, 6172 (1996). 12. A.J. Millis, T. Darling, and A. Migliori, J. Appl. Phys. 83, 1588 (1998). 888 Fizika Nizkikh Temperatur, 2003, v. 29, No. 8 V.G. Prokhorov, G.G. Kaminsky, V.A. Komashko, Y.P. Lee, and J.S. Park
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institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
issn 0132-6414
language English
last_indexed 2025-12-07T18:28:12Z
publishDate 2003
publisher Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
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spelling Prokhorov, V.G.
Kaminsky, G.G.
Komashko, V.A.
Lee, J.S.
Park, Y.P.
2018-01-14T12:18:24Z
2018-01-14T12:18:24Z
2003
Magnetic and transport properties of La₀.₈Sr₀.₂MnO₃/La₀.₈Ca₀.₂MnO₃ bilayer / V.G. Prokhorov, G.G. Kaminsky, V.A. Komashko, Y.P. Lee J.S. Park // Физика низких температур. — 2003. — Т. 29, № 8. — С. 885-888. — Бібліогр.: 12 назв. — англ.
0132-6414
PACS: 71.30.+h, 75.70.-i
https://nasplib.isofts.kiev.ua/handle/123456789/128902
The effects of lattice strain on the magnetic and the transport properties of La₀.₈Sr₀.₂MnO₃ films grown on an (001) LaAlO₃ substrate and on a La₀.₈Ca₀.₂MnO₃ layer were studied. It was observed that the metal-insulator and the ferromagnetic transitions occur at higher temperatures for the film deposited on La₀.₈Ca₀.₂MnO₃ layer than on LaAlO₃. The dependence of Curie temperature on the bulk and the Jahn-Teller strains were also determined.
This work was funded by the KOSEF through the Quantum Photonic Science Research Center.
en
Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
Физика низких температур
Низкотемпеpатуpный магнетизм
Magnetic and transport properties of La₀.₈Sr₀.₂MnO₃/La₀.₈Ca₀.₂MnO₃ bilayer
Article
published earlier
spellingShingle Magnetic and transport properties of La₀.₈Sr₀.₂MnO₃/La₀.₈Ca₀.₂MnO₃ bilayer
Prokhorov, V.G.
Kaminsky, G.G.
Komashko, V.A.
Lee, J.S.
Park, Y.P.
Низкотемпеpатуpный магнетизм
title Magnetic and transport properties of La₀.₈Sr₀.₂MnO₃/La₀.₈Ca₀.₂MnO₃ bilayer
title_full Magnetic and transport properties of La₀.₈Sr₀.₂MnO₃/La₀.₈Ca₀.₂MnO₃ bilayer
title_fullStr Magnetic and transport properties of La₀.₈Sr₀.₂MnO₃/La₀.₈Ca₀.₂MnO₃ bilayer
title_full_unstemmed Magnetic and transport properties of La₀.₈Sr₀.₂MnO₃/La₀.₈Ca₀.₂MnO₃ bilayer
title_short Magnetic and transport properties of La₀.₈Sr₀.₂MnO₃/La₀.₈Ca₀.₂MnO₃ bilayer
title_sort magnetic and transport properties of la₀.₈sr₀.₂mno₃/la₀.₈ca₀.₂mno₃ bilayer
topic Низкотемпеpатуpный магнетизм
topic_facet Низкотемпеpатуpный магнетизм
url https://nasplib.isofts.kiev.ua/handle/123456789/128902
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