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1

Growth and Investigation of p-La_{2/3}Ca_{1/3}MnO_3/n-Si Heterostructures

100%

Anisimovas F., Butkutė R., Devenson J., Maneikis A., Stankevič V., Pyragas V., Vengalis B.

Acta Physica Polonica A

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2008

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vol. 113

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issue 3

997-1000

EN

We report the fabrication and investigation of p-n diode structures based on thin hole-doped La_{2/3}Ca_{1/3}MnO_3 films grown on n-type silicon substrates. La_{2/3}Ca_{1/3}MnO_3 films with typical thickness of about 400 nm were prepared using pulsed laser deposition. Reflection high-energy electron diffraction measurements revealed polycrystalline quality of La_{2/3}Ca_{1/3}MnO_3 thin films on Si substrates. The surface roughness of La_{2/3}Ca_{1/3}MnO_3 films investigated by atomic force microscopy was found to be in the range of 25÷30 nm. Studies of electrical properties showed that La_{2/3}Ca_{1/3}MnO_3/Si heterostructures exhibit nonlinear asymmetric I-V characteristics both at room temperature and at 78 K. Furthemore, it was shown that these I-V dependences are sensitive to magnetic field, especially at lower voltages.

2

Reversible Resistive Switching in Electrically Nonhomogeneous La_{0.67}Ca_{0.33}MnO_3 Thin Films by Short Electrical Pulses

100%

Lučun A., Kiprijanovič O., Ašmontas S., Anisimovas F., Maneikis A., Sužied.lis A., Vengalis B.

Acta Physica Polonica A

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2008

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vol. 113

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issue 3

1059-1062

EN

Resistance changes in thin electrically nonhomogeneous La_{0.67}Ca_{0.33}MnO_3 films were investigated using electrical pulses of nanosecond duration in the 80-300 K temperature range. Two types of reversible switching to higher resistive states with different starting temperature induced by series of the positive pulses were observed. Possible mechanisms of the resistance switching by short electrical pulses in the vicinity of T_m and at 80-90 K are discussed.

3

Investigation Details of Vortex Density in Laser-Written Π-Shaped Channel of YBCO Bridge by Means of I-V Dependences

84%

Steponaviciene L., Sulcas J., Jukna A., Jung G., Plausinaitiene V., Abrutis A., Maneikis A., Gong M., Sobolewski R.

Acta Physica Polonica A

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2011

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vol. 119

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issue 2

180-182

EN

A current-self-induced magnetic field H_{j}, such that H_{c1} < H_{j} < H_{c2} at T < T_{c}, penetrates a thin-film, type-II superconductor forming the Abrikosov magnetic vortex-antivortex pairs in the film's areas of weakest superconductivity. Our atomic force microscopy and scanning tunneling microscopy images confirm that in 50 μm wide, 100 μm long and 0.3 μm thick YBa_2Cu_3O_{7 - x} superconducting devices magnetic flux penetrates first into a 5 μm wide, Π-shaped and partially deoxygenated (x ≈ 0.2) channel for easy vortex motion. When the Lorentz force overcomes pinning force in the channel, the flux starts to move and its drift dissipates energy inducing dc voltage. This work reports on the density of coherently moving vortices along the channel vs. temperature in range from 0.93T_{c} to 0.97T_{c}. Our simulations show that the vortex density vs. temperature dependence extracted from I-V measurements of our devices follows the temperature dependence of magnetic field penetration depth and the coherence length of the superconductor.

4

Electroresistance of Electrically Nonhomogeneous La_{0.67}Ca_{0.33}MnO_3/MgO Thin Films

84%

Kiprijanovič O., Lučun A., Ašmontas S., Anisimovas F., Butkutė R., Maneikis A., Sužiedėlis A., Vengalis B.

Acta Physica Polonica A

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2007

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vol. 111

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issue 1

141-146

EN

Current and electrical field-induced electroresistive effects were investigated for La_{0.67}Ca_{0.33}MnO_3/MgO thin films demonstrating nanosized electrical inhomogeneities. Two different models based on enhanced conductivity of intergrain boundaries by injecting spin-polarized carriers from ferromagnetic grains and electrical field-enhanced hopping of carriers in high resistance intergrain media were carried out to explain nonlinear electrical properties of the films.

5

Magnetoresistance of Polycrystalline La_{0.7}Ca_{0.3}MnO_3 Films in a Microwave Magnetic Field

84%

Lučun A., Butkutė R., Maneikis A., Kiprijanovič O., Anisimovas F., Gradauskas J., Sužiedėlis A., Vengalis B., Kancleris Ž., Ašmontas S.

Acta Physica Polonica A

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2007

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vol. 111

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issue 1

147-152

EN

We present new experimental evidence indicating the importance of magnetic field component of microwave field (f=9.4 GHz) for magnetoresistive properties of polycrystalline La_{0.7}Ca_{0.3}MnO_3 films. The microwave measurements revealed a different character of the temperature-dependent electrical resistance of polycrystalline La_{0.7}Ca_{0.3}MnO_3 films placed in the centre (maximal amplitude of H_{10} wave vector) and at a narrow wall of the wave-guide (reduced H_{10} amplitude). Theoretical estimations of the influence of substrate onto distribution of microwave electric and magnetic fields in the waveguide were performed using the finite-difference time-domain method.

6

Study of Terahertz Emission from Surfaces of Cu(InGa)Se_2 Layers

84%

Koroliov A., Arlauskas A., Balakauskas S., Šoliūnas M., Maneikis A., Krotkus A., Šetkus A., Tamošiūnas V.

Acta Physica Polonica A

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2013

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vol. 124

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issue 5

846-848

EN

In this contribution, we report on investigations of THz emission from Cu(In,Ga)Se_2 layers, deposited from a single copper-deficient sputtering target. Emission from Cu(In,Ga)Se_2 layer surface and from multilayer structure with transparent ZnO layers were studied. It was determined that additional undoped ZnO layer reduces the amplitude of THz emission, while additional n-type ZnO layers increase the emission amplitude again. This effect can be attributed to stronger electric field in the heterostructure between p-type Cu(In,Ga)Se_2 and n-type ZnO layers.

7

Growth and Investigation of Heterostructures Based on Multiferroic BiFeO_3

84%

Vengalis B., Devenson J., Oginskis A., Butkutė R., Maneikis A., Steikūnienė A., Dapkus L., Banys J., Kinka M.

Acta Physica Polonica A

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2008

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vol. 113

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issue 3

1095-1098

EN

We report heteroepitaxial growth of multiferroic BiFeO_3 thin films by RF magnetron sputtering on lattice-matched SrTiO_3 substrates, as well as preparation and electrical properties of the heterostructures formed by growing BiFeO_3 thin films on highly conductive LaNiO_3 films and n-Si substrates. Nonlinear and rectifying current-voltage (I-U) characteristics were revealed for the heterojunctions in a wide temperature range (T=78-300 K).

Refine search results

Growth and Investigation of p-La_{2/3}Ca_{1/3}MnO_3/n-Si Heterostructures

Reversible Resistive Switching in Electrically Nonhomogeneous La_{0.67}Ca_{0.33}MnO_3 Thin Films by Short Electrical Pulses

Investigation Details of Vortex Density in Laser-Written Π-Shaped Channel of YBCO Bridge by Means of I-V Dependences

Electroresistance of Electrically Nonhomogeneous La_{0.67}Ca_{0.33}MnO_3/MgO Thin Films

Magnetoresistance of Polycrystalline La_{0.7}Ca_{0.3}MnO_3 Films in a Microwave Magnetic Field

Study of Terahertz Emission from Surfaces of Cu(InGa)Se_2 Layers

Growth and Investigation of Heterostructures Based on Multiferroic BiFeO_3