**11. References**

344 Advances in Crystallization Processes

**100 200 300 400 500 600 700**

**o C)**

**Heating Temperature (**

Sol-gel-derived HfO2, ZrO2 and Y doped ZrO2(ZrO2-Y2O3) thin films on Si(001) wafers fired in air between 350 and 700 °C were characterized physically, chemically and electrically with the aim of achieving alternative gate insulator materials for advanced CMOS devices. Crystallinity of the sol-gel-derived HfO2, ZrO2 films was found to be dependent on the firing temperature and sol solution. The relative permittivity of the films converged to that of bulk HfO2 and ZrO2 according to the specific sol solutions and firing temperatures. Residual H2O and OH groups in the thin films were evaluated in reference to electrical characteristics such as the leakage current of MOS capacitors. The surface of the ZrO2-Y2O3 thin films on Si(001) wafers showed less roughness than the HfO2 and ZrO2 thin films, resulting in lower leakage current in MOS capacitors. The leakage current of crystallized ZrO2-Y2O3 thin films was shown to be lower than that of the amorphous state films because of the smooth crystalline surface of the latter in comparison with the ZrO2 thin films. In conclusion, crystalline sol-gelderived ZrO2-Y2O3 thin films are postulated to be promising as alternative gate insulator

Fig. 30. TPD curves of H2O (*m*/*z* = 18) that evolved from sol-gel-derived ZrO2-Y2O3 thin

films on Si(001) wafers, which were fired at (a) 350 and (b) 700 °C for 30 min

**700 <sup>o</sup> C**

**350 <sup>o</sup> C**

**0**

materials of advanced CMOS devices.

**2**

**4**

**6**

**Intensity (A)**

(Shimizu & Nishide, 2011)

**9. Conclusion** 

**8**

**10**

**12**

×**10-10**


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**14** 

*1Malaysia 2Iran* 

**Crystalization in Spinel Ferrite Nanoparticles** 

The enhanced interest of the researchers in nanoobjects is due to the discovery of unusual physical and chemical properties of these objects, which is related to manifestation of so-called 'quantum size effects'. These arise in the case where the size of the system is commensurable with the de-Brogli wavelengths of the electrons, phonons or excitons propagating in them.A key reason for the change in the physical and chemical properties of small particles as their size decreases is the increased fraction of the surface atoms, which occur under conditions (coordination number, symmetry of the local environment, etc.) differing from those of the bulk atoms. From the energy standpoint, a decrease in the particle size results in an increase in the fraction of the surface energy in its chemical potential [1]. Currently, unique physical properties of nanoparticles are under intensive research [2]. A special place belongs to the magnetic properties in which the difference between a massive (bulk) material and a nanomaterial is especially pronounced.The magnetic properties of nanoparticles are determined by many factors, the key of these including the chemical composition, the type and the degree of defectiveness of the crystal lattice, the particle size and shape, the morphology (for structurally inhomogeneous particles), the interaction of the particle with the surrounding matrix and the neighbouring particles. By changing the nanoparticle size, shape, composition and structure, one can control to an extent the magnetic characteristics of the material based on them. However, these factors cannot always be controlled during the synthesis of nanoparticles nearly equal in size and chemical composition; therefore, the properties of nanomaterials of the same type can be markedly different [1].Apart from these factors, the magnetic properties of particles depend on the external conditions: temperature, pressure and, in some cases, the local environment, i.e., the medium in which the particle occurs, in particular, the crystalline or amorphous bulk matrix (for a particle), the local crystal

Among the magnetic materials that have found broad practical application in technology, ferrites deserve attention. Ferrite nanoparticles are the most explored magnetic nanoparticles up to date. They are widely used in high-frequency applications, because an AC field does not induce undesirable eddy currents in an insulating material [3,4].To increase the recorded information density, it seems reasonable to obtain nanocrystalline

environment (for a single atom) or the substrate (for a film).

**2. Ferrites and their structural symmetries** 

**1. Introduction** 

Mahmoud Goodarz Naseri1,2 and Elias B. Saion1

*1Universiti Putra Malaysia, 2Malayer University,* 

