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The colossal magnetoresistive insulator to metal switching of almost nine orders of magnitude under the significantly reduced magnetic field is achieved by illumination for the low bandwidth manganite thin films. Similarly, by changing the measuring bias voltage through the sample the required magnetic field for insulator-metal transition can be further fine-tuned. By applying a magnetic field of suitable strength, the samples can also be tuned to be extra sensitive to the illumination having colossal effect on the resistivity at low temperatures. This kind of utilizing of multiple external stimulants, which together change the properties of the material, could have significant impact on the new generation of phase-change memories working under affordable conditions. [ABSTRACT FROM AUTHOR]

Photo-induced magnetization has been studied in small-bandwidth manganite PrCaMnO ( x = 0.1) (PCMO) bulk and thin films. It is observed that the persistent change in magnetization under optical excitation is much stronger in epitaxial thin films of PCMO compared to the bulk. This change is manifested in a change of both coercive field and Curie temperature of the thin films. Stronger photo-induced effect in the thin films might have their origin in the substrate-induced strain effect on the magnetic properties. [ABSTRACT FROM AUTHOR]

The accommodation field, B*, is generally defined to be the field at which the cross over from single vortex pinning to collective pinning occurs. It is determined from magnetization curves as the point where the Jc plateau ends and it used as a convenient way of comparing the pinning properties of superconducting films. Similarly, the characteristic field, Bc, can be obtained from magneto-optical (MO) images from when the flux fronts meet in the middle of the film. The matching field, Bc at which there is one vortex line per pinning site, is sometimes thought to be the same as B*, but in BaZrO3-doped YBa2Cu3O7 films the calculated BΦ, is much higher than the observed B*. BΦ, can be determined from angular dependent transport measurements. All of the field values correspond to some special case in the flux pinning in the film and relate to Jc. In this work we have determined Bc, B * and BΦ, for different kinds of YBCO films using MO, magnetization and transport measurements to reveal the deeper meaning of the special fields. [ABSTRACT FROM AUTHOR]

Superconducting YBa2Cu3O6+x (YBCO) films are grown by pulsed laser deposition (PLD) in the orientation where its c-axis is lying in the plane of the film using (110) oriented SrTiO3 (STO) substrates with PrBCO template layer. By optimization of deposition temperature and rate the easily formed (103) orientation was avoided to get smooth and completely (110) oriented YBCO films. To improve the superconducting properties, we have also optimized the BaZrO3 (BZO)-doping in the (110) YBCO films. This gives the possibility to apply the current along the YBCO CuO2 planes where the critical current is much higher in thin film multilayers or to investigate the anisotropy and the effect of BZO pinning structure in different film orientations. [ABSTRACT FROM AUTHOR]

We report the effect of 4 wt% BZO-doping in GdBCO thin films on (100) STO substrates with novel nanograined target materials deposited by pulsed laser deposition (PLD) method. X-ray diffraction, atomic force microscopy and magnetization measurements, which were made in particularly wide temperature and magnetic field range, were used to determine the structural and superconducting properties. The results were compared with ones of YBCO. The deposition temperature, Ts, is not very critical for GdBCO and it is found to be much lower in undoped and BZO-doped GdBCO than in YBCO. The BZO-doping of GdBCO enhanced the field dependence of critical current density, jc, at low temperatures. Furthermore, BZO-doping enhances the accommodation field, B*, below 60 K being clearly higher at 10 K in doped GdBCO than in YBCO. The pinning mechanism in GdBCO was concluded to be similar to that of YBCO. Our results clearly show that undoped and BZO-doped nanophase GdBCO is a very promising target material for applications as well as for coated conductors. [ABSTRACT FROM AUTHOR]

Striving to improve the critical current density Jc of superconducting YBa2Cu3O6+x (YBCO) thin films via enhanced vortex pinning, the interplay between film growth mechanisms and the formation of nanosized defects, both natural and artificial, is systematically studied in undoped and BaZrO3 (BZO)-doped YBCO thin films. The films were grown via pulsed laser deposition (PLD), varying the crystal grain size of the targets in addition to the dopant content. The microstructure of the PLD target has been observed to have a great impact on that of the deposited thin films, including the formation of vortex pinning centers, which has direct implications on the superconducting performance, especially on the isotropy of flux pinning properties. Based on experimentally measured angular dependencies of Jc, coupled with a molecular dynamics (MD) simulation of flux pinning in the YBCO films, we present a quantitative model of how the splay and fragmentation of BZO nanorods artifically introduced into the YBCO film matrix explain the majority of the observed critical current anisotropy. [ABSTRACT FROM AUTHOR]

A method of producing high-quality thin films of perovskite manganites utilizing citrate-based aqueous chemical solution deposition is presented. The method is applied to the production of thin films of gadolinium calcium manganite, Gd 1 − x Ca x MnO 3 (GCMO). The film quality is verified by x-ray diffraction analysis, electron microscopy, and magnetic measurements. Finally, planar memristors are fabricated using GCMO films, demonstrating the material's ability to exhibit resistive switching. This underscores its potential for future memristor technologies. • Gd 1 − x Ca x MnO 3 thin films can be manufactured in a scalable and cost-effective process. • Environmentally friendly water based chemical solution method is used. • The films produced are of sufficiently high quality for memristor applications. [ABSTRACT FROM AUTHOR]

We report photo-induced colossal magnetoresistive insulator-metal transition (IMT) in Pr 0.6 Ca 0.4 MnO 3 thin films under much reduced applied magnetic field. The colossal effect was studied as a function of film thickness and thus with variable structural properties. Thorough structural, magnetic and magnetotransport characterization under light shows that the highest effect on the transition field can be obtained in the thinnest film (38 nm). However, due to the substrate induced strain of this film the required magnetic field for IMT is quite high. The best crystalline properties of the 110 nm film lead to the lowest IMT field under light and 10 9 % change in resistance at 10 K. With increasing thickness, the film properties start to move more toward the bulk material and, hence, IMT is no more observed under the applied field of 9 T. Our results indicate that for obtaining large photo-induced CMR, the best epitaxial quality of thin films is essential. [ABSTRACT FROM AUTHOR]