Transition from spin glass to paramagnetism in the magnetic properties of PrAu2Si2

It is unexpected that a spin-glass transition, which generally occurs only in system with some form of disorder, was observed in the ThCr2Si2-type compound PrAu2Si2 at a temperature of 3 K. This puzzling phenomenon was later explained based on a novel dynamic frustration model that does not involve static disorder. We present the results of re-verification of the reported spin-glass behaviors by measuring the physical properties of three polycrystalline PrAu2Si2 samples annealed under different conditions. Indeed, in the sample annealed at 827 ◦C for one week, a spin-glass transition does occur at a temperature of T f~2.8 K as that reported previously in the literature. However, it is newly found that the spin-glass effect is actually more pronounced in the as-cast sample, and almost completely disappears in the well-annealed (at 850 ◦C for 4 weeks) sample. The annealing effect observed in PrAu2Si2, that is, spin glass to paramagnetism transition is discussed by comparing with earlier results reported on the same system and other isomorphic compounds.

Annealing Effect on One Step Electrodeposited CuSbSe2 Thin Films

The purpose of this work is to study the influence of the annealing temperature on the structural, morphological, compositional and optical properties of CuSbSe2 thin films electrodeposited in a single step. CuSbSe2 thin films were grown on fluorine-doped tin oxide (FTO)/glass substrates using the aqueous electrodeposition technique, then annealed in a tube furnace under nitrogen at temperatures spanning from 250 to 500 °C. The resulting films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis, Raman spectroscopy and UV-Vis spectrophotometer. The annealing temperature plays a fundamental role on the films structural properties; in the range 250–350 °C the formation of pure CuSbSe2 phase from electrodeposited binary selenides occurs. From 400 to 500 °C, CuSbSe2 undergoes a preferential phase orientation change, as well as the increasing formation of copper-rich phases such as Cu3SbSe3 and Cu3SbSe4 due to the partial decomposition of CuSbSe2 and to the antimony losses.

Annealing effect of absorber layer on SnS/CdS heterojunction band alignments

The effect of annealing on physical properties of a SnS thin film and also on SnS/CdS heterojunction band alignment was studied. Vacuum annealing has greatly improved the crystalline quality of SnS and average grain size of 1.6 µm was achieved. Sulfur-rich secondary phases observed on the surface of as-grown SnS thin film were eliminated after vacuum annealing, resulting in a decrease of the resistivity and an increase of the carrier concentration of the film. A maximum hole mobility of 17 cm2V-1s-1 was obtained for SnS thin films annealed at 400 ֯C. A transition of SnS/CdS heterojunction from “spike” type to “cliff” type was observed when the vacuum annealed SnS thin film was post-air-annealed at 200 and 250 ֯C. The band alignment of SnS/CdS heterojunction could be adjustable between “spike” type to “cliff” type via vacuum annealing followed by post-air-annealing.