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Integrating multiple functions in a single compound is still attractive and necessary to meet the demand of device miniaturization. In this work, we systemically modulate multifunctional properties in the 0.74BiFeO3–0.26(Ba0:85Ca0:15)TiO3–x wt. % MnO2 solid solution with the addition of MnO2. A highly rectangular and saturated polarization–hysteresis (P–E) loop is obtained with a large remanent polarization Pr of 49.5 μC/cm² as x = 0:8. Furthermore, the piezoelectric coefficient d33 also obviously improved with an optimized d33 = 137 pC/N by the introduction of MnO2 due to the grain size effect, the improvement of insulation, and relaxation regulation. With the addition of MnO2, the remanent magnetization Mr increases monotonically because of the enhanced exchange interactions between Fe2+and Fe3+. The results may provide an effective way to explore promising multifunctional materials in BiFeO3-based ceramics. [ABSTRACT FROM AUTHOR]

High coercivity CoFe2O4 (CFO) thin films with large-area are very desirable for applications. Here, we report La0.7Sr0.3MnO3 (LSMO) layer decoration effects on coercivity in CFO thin films by solution processing. With LSMO layer decoration, the coercivity increases initially and then decreases with increasing LSMO layer thickness. Strain induced by the mismatched thermal expansion coefficient and magnetostrictive coefficient as well as the interfacial magnetic exchange coupling between CFO and LSMO are investigated. The room temperature out-of-plane and in-plane coercivity reached 7.6 and 4.9 kOe, respectively, are obtained, which are the highest values in solution derived CFO thin films. The improved coercivity is beneficial for applications and provides a facile route to enhance coercivity of CFO thin films through surface modification by soft magnetic layers. [ABSTRACT FROM AUTHOR]

Upper critical field of polycrystalline δ-Mo1-xZrxN ( 0x0.3) thin films by sol-gel was investigated. It showed that the upper critical field was continuously improved with Zr doping content, and the improvement of10 T in upper critical field was mainly attributed to the combined effects of obvious enhancements in normal-state resistivity with slight changes in Tc, obvious decrease in crystallite/grain size and enhanced microstrains. Flux jump was observed in low-level doped thin films due to enhanced critical current density by Zr doping. Finally, the vortex phase diagram of δ-Mo1-xZrxN thin films was presented, which will provide guidance for investigation about the vortex mechanisms of δ-Mo1-xZrxN thin films. [ABSTRACT FROM AUTHOR]

Nanosized (Sr2FeMoO6)1-x/(CeO2)x composites were prepared by Sr2FeMoO6 (SFMO) obtained by sol-gel and nanosized CeO2 powders. The magnetoresistance (MR) of composites is explored as a function of the molybdate/insulator composition and magnetic field. The enhancement of the low-field magnetoresistance is observed with increasing CeO2. The MR ratio at 10 K with H=5 kOe is 7.9% and 10.2% for the x=0.05 and 0.3 samples, which are 1.1 times and 1.7 times as large as that for pure SFMO, respectively. The enhanced MR was attributed to the spin-dependent tunneling at the interface of grain boundaries. [ABSTRACT FROM AUTHOR]

High room temperature coercivity CoFe2O4 (CFO) thin films are desirable in view of many applications, which is seldom achieved over 3 kOe in solution deposited CFO thin films. Herein, grain growth kinetic is investigated in the solution derived CFO thin films with coercivity larger than 4 kOe, showing a relaxation mechanism. The coercivity and magnetization increase initially and then decrease with increasing dwell time. The high coercivity is originated mainly from the critical grain size and the growth strain induced by the small crystallites and poorly developed grains. The results will provide a route to fabricate larger-area CFO thin films with high coercivity on silicon wafers by low-cost solution processing. [ABSTRACT FROM AUTHOR]

A high magnetic field assisted pulsed laser deposition (HMF-PLD) system has been developed to in situ grow thin films in a high magnetic field up to 10 T. In this system, a specially designed PLD cylindrical vacuum chamber is horizontally located in the bore configuration of a superconducting magnet with a bore diameter of 200 mm. To adjust the focused pulsed laser into the target in such a narrow PLD vacuum chamber, an ingeniously built-in laser leading-in chamber is employed, including a laser mirror with a reflection angle of 65∠ and a damage threshold up to 3.4 J/cm². A laser alignment system consisting of a built-in video-unit leading-in chamber and a low-energy alignment laser is applied to monitor and align the pulsed laser propagation in the PLD vacuum chamber. We have grown La0.7Sr0.3MnO3 (LSMO) thin films on (LaAlO3)0.3(Sr2AlTaO6)0.7 (001) [LSAT (001)] substrates by HMF-PLD. The results show that the nanostructures of the LSMO films can be tuned from an epitaxially continuous film structure without field to a vertically aligned nanorod structure with an applied high magnetic field above 5 T, and the dimension size of the nanorods can be tuned by the strength of the magnetic field. The associated magnetic anisotropy is found to be highly dependent on the nanorod structures. We show how the HMF-PLD provides an effective route toward tuning the nanostructures and the physical properties of functional thin films, giving it an important role in development of nanodevices and their application. [ABSTRACT FROM AUTHOR]

We investigated the superconducting transition temperature Tc of FeSe0.5Te0.5 single crystals, which can be enhanced up to 14% by attaching onto a commercial Scotch tape. The Scotch tape exhibits a large cooling shrinkage at low temperatures, which is considerably more pronounced than that of the metallic FeSe0.5Te0.5 single crystal, thus providing a compressive strain of 2.4 x 10-3 at 15 K. For such strain, we calculated that the lattice parameter of c/a can be increased to ~0.31%, which corresponds to the enhancement of the superconductivity. The present finding provides a rapid and simple method to examine the microstructure sensitive physical properties of the layered-structure materials by using the Scotch tape as strain generator. [ABSTRACT FROM AUTHOR]

In the superconductor of FeSe0.5Te0.5, the superconductivity is highly sensitive to variations of microstructure. Therefore, a fine manipulation of the microstructures will be crucial not only for a better understanding of the superconductivity but also for potential applications. Here, we demonstrate an approach to control the superconductivity in-situ by using a magnetostrictive substrate ZnCr2Se4 as the strain generator. By mounting an FeSe0.5Te0.5 single crystal onto a magnetostrictive substrate, we show that the magnetoresistance of FeSe0.5Te0.5 is directly coupled to the magnetostriction of ZnCr2Se4. The strain is fine-tuned in-situ by an external magnetic field, leading to the superconductivity of FeSe0.5Te0.5 correspondingly favored by compressive strain while suppressed by tensile strain. [ABSTRACT FROM AUTHOR]

In the superconductor of FeSe0.5Te0.5, the superconductivity is highly sensitive to variations of microstructure. Therefore, a fine manipulation of the microstructures will be crucial not only for a better understanding of the superconductivity but also for potential applications. Here, we demonstrate an approach to control the superconductivity in-situ by using a magnetostrictive substrate ZnCr2Se4 as the strain generator. By mounting an FeSe0.5Te0.5 single crystal onto a magnetostrictive substrate, we show that the magnetoresistance of FeSe0.5Te0.5 is directly coupled to the magnetostriction of ZnCr2Se4. The strain is fine-tuned in-situ by an external magnetic field, leading to the superconductivity of FeSe0.5Te0.5 correspondingly favored by compressive strain while suppressed by tensile strain. [ABSTRACT FROM AUTHOR]