共查询到20条相似文献,搜索用时 0 毫秒
1.
Jitendra Kumar P.K. Siwach Ramadhar Singh O.N. Srivastava 《Solid State Communications》2006,138(8):422-425
We report a large enhancement (∼90%) in magnetoresistance in La0.82Sr0.18MnO3 (LSMO) layers by incorporating a π-conjugated semiconducting polymer layer in between them. The epitaxial LSMO layers were deposited by DC magnetron sputtering on SrTiO3 single crystal substrates and have FM transition temperature (TC)∼310 K. A semiconducting polymer poly(3-octylthiophene) (P3OT) layer was deposited over the epitaxial LSMO layer by solution dip coating technique and with subsequent deposition of another epitaxial LSMO layer, forming a LSMO-P3OT-LSMO heterostructure. The effect of P3OT incorporation on magnetotransport properties of this heterostructure has been examined in the temperature range 77-350 K. Large MR enhancement observed near room temperature in the FM regime is explained in terms of efficient magnetic field dependent carrier injection at LSMO/P3OT interface. 相似文献
2.
Niebieskikwiat D Hueso LE Borchers JA Mathur ND Salamon MB 《Physical review letters》2007,99(24):247207
We use polarized neutron reflectometry and dc magnetometry to obtain a comprehensive picture of the magnetic structure of a series of La(2/3)Sr(1/3)MnO3/Pr(2/3)Ca(1/3)MnO3 (LSMO/PCMO) superlattices, with varying thickness of the antiferromagnetic (AFM) PCMO layers (0相似文献
3.
In this work we present a magnetic study of La0.67Sr0.33MnO3 (LSMO) and La0.67Ca0.33MnO3 (LCMO) nanotubes with nominal external diameters (?) of 100, 200, 600 and 800 nm. The 800 nm diameter nanotubes have walls of around 50 nm thickness in all the cases. The walls are constituted by an assembly of nanoparticles with a non-Gaussian size distribution presenting a maximum at 24 ± 6 nm (LSMO) and 25 ± 8 nm (LCMO). We carried out isothermal remanent magnetization (IRM) and dc demagnetization (DCD) experiments. We determined that the crystallites are single magnetic domains with a magnetic dead layer on the surface which avoids exchange interactions among grains. We conclude that the dominating interactions are of dipolar type of the same magnitude for all the samples. 相似文献
4.
The perovskite bilayers La0.67Ca0.33MnO3 (LCMO) (100 nm) / La0.67Sr0.33MnO3(LSMO) (100 nm) and LSMO (100 nm) / LCMO (100 nm) are fabricated by a facing-target sputtering technique. Their transport and magnetic properties are investigated. It is found that the transport properties between them are different obviously due to distinguishable structures, and the different lattice strains in both films result in the difference of metal-to-insulator transition. Only single-step magnetization loop appears in our bilayers from 5K to 320K, and the coercive force of LSMO/LCMO varies irregularly with a minimum ~ 2387A/m which is lower than that of LCMO and LSMO single layer films. The behaviour is explained by some magnetic coupling. 相似文献
5.
The La0.8Sr0.2MnO3 (LSMO)/ TiO2 heterostructures with different thicknesses of the LSMO films were successfully synthesized using the RF magnetron sputtering technique. Excellent rectifying characteristics are presented in all heterostructures in a wide temperature range. The differences of the diffusive potentials for three heterojunctions are very little at 300 K. The samples exhibit a high resistance that plays an important role on their rectifying properties. The diffusive potential decreases with increasing temperature. The result is attributed to both the reduction of the thickness of the deletion layer due to the thermal diffusion and the modulation of the interfacial electronic structure of the heterostructures. The metal-insulator (M-I) transition is observed clearly from the single LSMO layers and the LSMO/ TiO2 p-n heterojunctions. 相似文献
6.
The origination of ill-defined layer in organic spin valves was investigated by using atomic force microscopy (AFM) and Rutherford backscattering (RBS) analysis. It was found that conductive bulges of LSMO film and self-grown pinholes in Alq3 film other than Co inclusions could lead to the formation of ill-defined layer. The morphology of LSMO substrate had a strong influence on that of Alq3 film, LSMO/Alq3 and Alq3/Co interfaces. Moreover, Alq3 film with the thickness of 1-4 nm could be barriers which was explained by small active area and added insulated layer in organic magnetic tunnel junctions. 相似文献
7.
Ferromagnetic La0.7Sr0.3MnO3 (LSMO) and antiferromagnetic La0.33Ca0.67MnO3 (LCMO) layers were grown on SrTiO3 (STO) substrates by the pulsed laser deposition technique. LSMO films had rougher surfaces and larger grain sizes than LCMO films. Fully strained bilayers, in which each layer was as thin as 10 nm, were prepared by changing their stacking sequences, i.e. LSMO/LCMO/STO and LCMO/LSMO/STO. The former had higher TC (350 K) than the latter (300 K), and exchange bias effects were only observed in the former bilayers. This revealed that microstructures could play an important role in the transport and magnetic properties of manganese oxide thin films. 相似文献
8.
Dong-Wook Kim 《Solid State Communications》2006,137(10):545-548
A pulsed laser deposition technique was used to grow ferromagnetic La0.7Sr0.3MnO3 (LSMO) films on antiferromagnetic La0.33Ca0.67MnO3 (LCMO) and Pr0.7Ca0.3MnO3 (PCMO) films in bilayer forms. The LSMO film on the PCMO layer had a more elongated out-of-plane lattice than that on the LCMO layer. The former had a lower ferromagnetic transition temperature (320 K) than the latter (350 K). The enhanced low-temperature magnetoresistance of the LSMO/PCMO bilayer suggests that the spin frustration is stronger at this bilayer than in the LSMO/LCMO bilayer. These differences indicate that strain state and defect concentration play important roles in governing interfacial spin interactions. 相似文献
9.
T. Tsuchiya T. Yoshitake Y. Shimakawa Y. Kubo Y. Yamaguchi T. Manabe T. Kumagai S. Mizuta 《Applied Physics A: Materials Science & Processing》2004,79(4-6):1537-1539
La0.8Sr0.2MnO3 (LSMO) films were prepared on LaAlO3 substrates by excimer laser metal organic deposition (ELMOD) at 500 °C. The temperature dependence of resistance of the LSMO films was investigated by changing the laser fluence, irradiation time, and film thickness. It was found that the resistance of the LSMO films 80 nm in thickness that were irradiated by an ArF laser at a fluence of 100 mJ/cm2 for 60 min showed a metallic temperature dependence, and the maximum temperature coefficient of resistance of the films (defined as 1/R×dR/dT) was 3.4% at 265 K. PACS 81.15.-z; 81.15.Fg; 81.15.Np; 73.61.-r; 71.30.+h 相似文献
10.
Daniel Hsu Yu-Han Tsai Zhongwen Xing Jauyn Grace Lin 《The European Physical Journal B - Condensed Matter and Complex Systems》2013,86(6):1-4
For Ag/Nd0.7Ca0.3MnO3/YBa2Cu3O7 (Ag/NCMO/YBCO) heterostructures, we investigate effects of an SrTiO3 (STO) buffer layer inserted into the Ag/NCMO interface upon the room-temperature resistive switching. In comparison with the non-buffered (Ag/NCMO/YBCO) structure, the insertion of the STO buffer layer can greatly enhance the electric-field-induced-resistance (EPIR) effect. The STO-buffered (Ag/STO/NCMO/ YBCO) device can be switched on-and-off between the higher to lower resistance states at an EPIR ratio of 253% with pulsed voltage ±1.5 V and 405% with pulsed voltage ±3.0 V. The enhanced EPIR ratio is attributed to a combined effect of the migration of oxygen vacancies near the interface and ferroelectric polarization of the STO buffer. 相似文献
11.
Qian Wan KuiJuan Jin JieSu Wang HongBao Yao JunXing Gu HaiZhong Guo XiuLai Xu GuoZhen Yang 《中国科学:物理学 力学 天文学(英文版)》2017,60(4):047511
The ultrafast laser-excited magnetization dynamics of ferromagnetic (FM) La0.67Sr0.33MnO3 (LSMO) thin films with BiFeO3 (BFO) coating layers grown by laser molecular beam epitaxy are investigated using the optical pump-probe technique. Uniform magnetization precessions are observed in the films under an applied external magnetic field by measuring the time-resolved magneto-optical Kerr effect. The magnetization precession frequencies of the LSMO thin films with the BFO coating layers are lower than those of uncoated LSMO films, which is attributed to the suppression of the anisotropy field induced by the exchange interaction at the interface between the antiferromagnetic order of BFO and the FM order of LSMO. 相似文献
12.
C.?M.?Kanamadi J.?S.?Kim H.?K.?Yang B.?K.?Moon B.?C.?Choi J.?H.?Jeong 《Applied Physics A: Materials Science & Processing》2009,96(3):575-580
Composite structures consisting of (001)-oriented SrTiO3 (STO)/La0.7Sr0.3MnO3 (LSMO) films of 30 nm thickness, grown on an (001) Pb(Mg1/3Nb2/3)TiO3– 28 mol.% PbTiO3 piezoelectric relaxor-ferroelectric single-crystalline wafer were investigated by means of Wide-Angle X-ray Diffraction (WAXRD)
in situ under influence of a d.c. electric field with strength E up to ±18 kV/cm. The WAXRD measurements of the films and substrate reflection profiles resulted in a determination of the
strain s in the films and the substrate separately. The strained state of the STO/LSMO films is effectively controlled by a huge converse
piezoelectric effect of the PMN-PT substrate. The coefficients of coupling between electric-field-induced out-of-plane strain
in the films and in the substrate for the composite system STO/LSMO/PMN-PT are obtained. 相似文献
13.
《Current Applied Physics》2007,7(1):47-50
La0.7Sr0.3MnO3 (LSMO) manganite thin films were grown by pulsed plasma deposition on silicon (Si) and gallium arsenide (GaAs) substrates covered by an amorphous oxide. Manganite films are characterized by polycrystalline structure. Ferromagnetic transition is above room temperature and for 50 nm thick film the Curie temperature was as high as 325 K and 305 K for LSMO/SiOx/Si and LSMO/AlOx/GaAs, respectively. 相似文献
14.
Timur Nurgaliev Vladimír Štrbík Snezhanka Miteva Blagoi Blagoev Emil Mateev Lyubomir Neshkov Štefan Beňačka Štefan Chromik 《Central European Journal of Physics》2007,5(4):637-649
Superconductor/ferromagnetic (SC/FM) Y1Ba2Cu3O7−δ
/La0.7Sr0.3MnO3 (YBCO/LSMO) double layers were prepared on LaAlO3 substrates by magnetron sputtering and their electrical and microwave parameters were investigated at 77 K. In the theoretical
plan, simple formulas for estimation of the sensitivity of the SC surface impedance to the concentration changes of normal
charge carriers were proposed and the surface resistance R
S
peculiarities of both SC and FM surfaces were described. Thinner YBCO/LSMO structure was characterized by lower SC parameters
and higher surface resistance R
S
at ∼ 4 GHz. The difference of R
S
of sample SC surfaces was interpreted as due to a difference between the normal charge carrier densities in these samples.
R
S
of the FM surface was higher than that of the SC surface due to the microwave losses of the magnetic subsystem. A peak of
the microwave losses, observed in the thicker double layer, was assumed to be caused by uniform FMR in the LSMO film.
Presented at 5-th International Conference Solid State Surfaces and Interfaces, November 19–24, 2006, Smolenice Castle, Slovakia. 相似文献
15.
M. Belmeguenai S. Mercone C. Adamo T. Chauveau L. Méchin P. Monod P. Moch D. G. Schlom 《Journal of nanoparticle research》2011,13(11):5669-5675
Nearly 50-nm thick La0.7Sr0.3MnO3 (LSMO) films were grown on Si substrates using molecular beam epitaxy on (001) Si substrates over-layered by a 20 nm thick
SrTiO3 (STO) or by a 20 nm thick CaTiO3 (CTO) film. In addition, a reference LSMO film was directly deposited on a (001) STO substrate by pulsed laser deposition.
For all the samples, X-ray diffraction revealed an excellent epitaxy of the LSMO film and small mosaicity around (001), with
in-plane [100] and [010] cubic axes. The LSMO/CTO films are in-plane compressed while the LSMO/STO ones are in-plane extended.
The temperature dependence of their static magnetic properties was studied using a SQUID, showing a Curie temperature overpassing
315 K for all the samples. Hysteresis loops performed at room temperature (294 K) with the help of a vibrating sample magnetometer
(VSM) are also discussed. At 294 K Micro-strip ferromagnetic resonance (MS-FMR) was used to investigate the dynamic magnetic
properties. It allows concluding to a strong anisotropy perpendicular to the films and to a weak fourfold in-plane anisotropy
with easy axes along the [110] and [1[`1]0 1\bar{1}0 ] directions. Their values strongly depend on the studied sample and are presumably related to the strains suffered by the
films. 相似文献
16.
Phan Van Cuong Joonghoe Dho Hyo Yeol Park Do-Hyung Kim 《Applied Physics A: Materials Science & Processing》2009,95(2):567-571
This paper reports on the sonochemical-assisted synthesis of La0.7Sr0.3MnO3 (LSMO) nanoparticles (NPs) which have a single-crystalline perovskite structure. The average particle size of LSMO NPs was
controlled from about 40 to 120 nm by changing the annealing temperatures from 750 to 1050°C. The particle size, electrical
resistivity, and ferromagnetic transition temperature of LSMO NPs were strongly dependent on the annealing temperature. A
substantial decrease in resistivity and an enhancement in the insulator–metal transition temperature were found on increasing
the annealing temperature. Furthermore, the enhancement in magnetization and paramagnetic–ferromagnetic (PM–FM) transition
temperatures was observed as the annealing temperature increases. 相似文献
17.
The magnetocaloric effect (MCE) has been measured by direct method in La0.8Ag0.15MnO3 and La0.85Ag0.15MnO3 before and after coating of Fe–Co layer on the surfaces of manganites. An evaporated film thickness has been 500 nm. The measurements have shown the MCE to be increased by 7%–8% under 26 kOe after Fe–Co coating on the flat surfaces. 相似文献
18.
C. Zandalazini P. Esquinazi G. Bridoux J. Barzola-QuiquiaH. Ohldag E. Arenholz 《Journal of magnetism and magnetic materials》2011,323(22):2892-2898
We studied the magnetic behavior of bilayers of multiferroic and nominally antiferromagnetic o-YMnO3 (375 nm thick) and ferromagnetic La0.7Sr0.3MnO3 and La0.67Ca0.33MnO3 (8…225 nm), in particular the vertical magnetization shift ME and exchange-bias field HE for different thickness and magnetic dilutions of the ferromagnetic layer at different temperatures and cooling fields. We have found very large ME shifts equivalent to up to 100% of the saturation value of the o-YMO layer alone. The overall behavior, including XMCD magnetization shift measured at the Mn-L edge of the LSMO layer only, indicates that the properties of the ferromagnetic layer contribute substantially to the ME shift and that this does not correlate straightforwardly with the measured exchange-bias field HE. 相似文献
19.
Jinguo Huang Qiang Li 《Journal of Quantitative Spectroscopy & Radiative Transfer》2011,112(16):2592-2599
Combination of thermochromism of perovskite-type materials and gratings can result in some interesting variations of the spectral properties of structured surfaces. This paper aims at investigating thermal absorptive/radiative characteristics of structured thermochromic material La0.825Sr0.175MnO3 (LSMO) with metallic and/or dielectric gratings. Numerical computation is conducted to obtain the distribution of the spectral absorptance of such structured surfaces with different structural parameters. The directional and temperature dependence of absorptance are also analyzed. The results reveal that compared with bulk LSMO material, the structured surface of LSMO achieves an improved thermochromic performance and much thinner layer of a structured LSMO film by combining the film with one-dimensional Al and SiO2 gratings. Therefore, the other advantage of such structured surface is that the reduction of material consumption and weight is achieved due to the smaller LSMO layer thickness, which may be vital for thermal management of space vehicles. 相似文献
20.
Sujittra Daengsakul Charusporn Mongkolkachit Chunpen Thomas Sineenat Siri Ian Thomas Vittaya Amornkitbamrung Santi Maensiri 《Applied Physics A: Materials Science & Processing》2009,96(3):691-699
This study reports the new and simple synthesis of magnetic La0.7Sr0.3MnO3 (LSMO) nanoparticles by thermal decomposition method using acetate salts of La, Sr and Mn as starting materials. To obtain
the LSMO nanoparticles, thermal decomposition of the precursor is carried out at the temperatures of 600, 700, 800, 900, and
1000°C for 6 hours. The synthesized LSMO nanoparticles were characterized by XRD, FT-IR, TEM and SEM. Structural characterization
shows that the prepared particles consisted of two phases of LaMnO3 (LMO) and LSMO with crystallite sizes ranging from 18 to 55 nm. All the prepared samples have a perovskite structure which
changes from cubic to rhombohedral with the increase in the thermal decomposition temperature. Basic magnetic characteristics
such as saturation magnetization (M
S) and coercive field (H
C) are evaluated by sample vibrating magnetometry at room temperature (20°C). The samples show soft ferromagnetic behavior
with M
S values of ∼9–55 emu/g and H
C values of ∼8–37 Oe, depending on the crystallite size and thermal decomposition temperature. The relationship between the
crystallite size and the magnetic properties is presented and discussed. The cytotoxicity of synthesized LSMO nanoparticles
was also evaluated with NIH 3T3 cells and the result showed that the synthesized nanoparticles were not toxic to the cells
as determined from cell viability in response to the liquid extraction of LSMO nanoparticles. 相似文献