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Optimization of substrate heating during sputtering processes is essential to obtain desired microstructures of deposited thin films, as it provides the required energy flux during the nucleation and growth. In this work, Ge 2 Sb 2 Te 5 thin films were prepared by a pulsed-DC magnetron sputtering process at optimized plasma conditions (pulsed frequency and pulse reversal time). The effect of substrate heating, in temperature range of 250–450 °C, was systematically investigated on the process throughput and various properties i.e. microstructure, morphology, atomic composition, carrier concentration, mobility and Seebeck coefficient of deposited films. The substrate heating was found to be required to obtain films in cubic crystalline phase. Through the optimization of substrate temperature, process throughput and surface properties, electrical properties as well as thermoelectric power factors were enhanced. The maximum power factor value of thin films was achieved as 0.77 mW m –1  K –2 for the substrate temperature as 400 °C. [ABSTRACT FROM AUTHOR]

Ti doped ZnO (TZO) thin films are stabilized by means of sputtering on quartz substrates and their structural, optical and electronic structure studies are carried out. The effect of different substrate temperature during growth and post deposition annealing effect is emphasized in TZO films. Structural characterization reveals that the TZO films have a wurzite phase with (0001) preferred orientation and lattice strain tends to relax at higher growth temperature and lower growth rate. Crystallite size, lattice strain and the band gap demonstrate dependency on deposition parameters. Moreover, these are strongly influenced by post deposition annealing treatment. The changes induced in the electronic structure of TZO films due to varying deposition parameters and post annealing treatment are understood through X-ray absorption spectroscopy and X-ray absorption near-edge structure measurements. The secondary ion mass spectrometry predicts that concentration of Ti in TZO film is laterally homogeneous but is vertically modulated upon post annealing while the Zn and O have followed stable concentration profile. [ABSTRACT FROM AUTHOR]

Zero field cooled spontaneous exchange bias (SEB) is observed in self-assembled nanocomposite thin films of La 0.7 Sr 0.3 MnO 3 (LSMO):NiO grown on single crystal line SrTiO 3 (001) substrate by pulsed laser deposition. SEB is displayed by the asymmetry in the hysteresis loop of the composite film along with the field cooled conventional exchange bias (CEB) effect. The training effect shows that exchange bias relaxation is disorder mediated. It is revealed from DC magnetization measurements that such nanocomposite film divulges spin glass like behaviour, arising due to competing ferromagnetic and antiferromagnetic interactions at the assorted interfaces of ferromagnetic LSMO and antiferromagnetic NiO. X-ray magnetic circular dichroism (XMCD) measurements discern that SEB is mainly originating due to ferromagnetic coupling of unstable interfacial antiferromagnetic spin due to NiO with the ferromagnetic LSMO at the disordered interface. These results of self-assembled thin films provide a useful input to realize and understand microscopic origin of SEB for device application. • Self-assembled nanocomposite thin films of La 0.7 Sr 0.3 MnO 3 (LSMO):NiO grown on SrTiO 3 (001). • Zero field cooled spontaneous exchange bias (SEB), field cooled conventional exchange bias (CEB). • The training effect shows that exchange bias relaxation is disorder mediated. • Magnetization measurements reveals the presence of interfacial disordered glass like behaviour. [ABSTRACT FROM AUTHOR]