5 research outputs found
Magnetocaloric effect in La 0.7 Nd x Ba (0.3-x) MnO 3 (x = 0, 0.05, 0.1) perovskite manganites
We have synthesized La 0.7 Nd x Ba (0.3-x) MnO 3 (x = 0, 0.05, 0.1) perovskite manganites by using sol-gel method and investigated structure, magnetic and magnetocaloric properties. Structural analysis revealed that La 0.7 Ba 0.3 MnO 3 and La 0.7 Nd 0.05 Ba 0.25 MnO 3 have cubic and La 0.7 Nd 0.1 Ba 0.2 MnO 3 rhombohedral structure. The Curie temperature of the samples decreased with increasing Nd content and equals to 303, 293 and 257 K for x = 0, 0.05, 0.1, respectively. We present experimentally by using magnetization isotherms and heat-capacity measurements that room temperature magnetic refrigeration is successfully achieved for La 0.7 Nd 0.05 Ba 0.25 MnO 3 structure by tuning the Mn 3+ to Mn 4+ ratio. Additionally, zero-field and field-dependent heat-capacity measurements were compared to investigate the accuracy of the value of the adiabatic temperature-change. © 201
All-fiber nanosecond laser system generating supercontinuum spectrum for photoacoustic imaging
[No abstract available
The effect of thickness on surface structure of rf sputtered TiO<inf>2</inf> thin films by XPS, SEM/EDS, AFM and SAM
In the current study, silicon was utilized as the substrate material
and, then, the TiO2 depositions with 100 nm, 300 nm, 500 nm and 700 nm
were done onto substrates as thin films at room temperature by a radio
frequency (rf) magnetron sputtering method. The binding energy, the
surface roughness, elemental analysis and the specific acoustic
impedance have been determined via X-ray photoelectron spectroscopy
(XPS), atomic force microscopy (AFM), scanning electron
microscopy/energy dispersive spectroscopy (SEM/EDS) and scanning
acoustic microscopy (SAM), respectively. AFM analysis represented that
the root mean square roughness values changed in the range of 0.72
nm-1.22 nm, gradually by the increase in thickness. Two-dimensional
acoustic images were recorded by SAM with 80 MHz transducer. The mean
and standard deviation values of acoustic impedance were found as 3.151
+/- 0.080 MRayl for 100 nm, 3.366 +/- 0.080 MRayl for 300 nm, 3.379 +/-
0.067 MRayl for 500 nm and, 3.394 +/- 0.065 MRayl for 700 nm. SAM
results pointed out that the hardness of films increased with increasing
thickness. Moreover, the surface defects at the micrometer level were
demonstrated. The success of imaging films indicated the potential of
SAM in monitoring as well as the inspection of flat two-dimensional
surfaces