Kenjiro Kambe

Effect of substrate temperature on crystallization of amorphous antimony film.

A study is made of the crystallization of amorphous antimony film deposited on a glass substrate. The substrate is maintained at a desired temperature between 20°C and 90°C. The crystal growth in the films of thickness 210-550 A is directly observed through an optical microscope. At any substrate temperature Ts the rate of crystal growth v is found to change with the thickness d in accordance with the expression v=v∞(1-dc/d), where dc is the critical thickness for crystallization of the amorphous antimony film and v∞ the rate of crystal growth for bulk antimony. The critical thickness dc decreases with the rise of Ts. The activation energy of atoms for crystallization Q is found to be 0.32 eV for bulk antimony.

Crystallization of amorphous antimony films deposited onto glass substrates in ultrahigh vacuum

Abstract The crystallization of amorphous antimony (a-Sb) films deposited onto glass substrates in an ultrahigh vacuum of 10−6−10−7 Pa is investigated through in situ observation with an optical microscope camera. In comparison with the results for deposition in a conventional vacuum of 10−4−10−5 Pa, a marked reduction is observed in the critical thickness dc for crystallization. For thicknesses less than the previous dc value of about 250 A, the dependence of the crystallization rate on the thickness is found to weaken drastically and the activation energy of the atoms for crystallization to increase. The antimony crystallites which nucleate in such thin a-Sb films do not take a simple spherical form.

Crystallization of amorphous antimony films on silver films

Abstract The crystallization process in amorphous antimony films 70–330 A thick evaporated onto silver films 10–150 A thick which have previously been evaporated onto glass is directly observed through an optical microscope. The conditions under which the crystallization process in the amorphous antimony films is observed are found to be severely limited by the preparation conditions of the silver films. The crystallization can only be observed on silver films thinner than 30–40 A which have previously been exposed to oxygen or nitrogen gas. The crystallization thickness of amorphous antimony films on these substrates is estimated to be 123-75 A as the substrate temperature varies from 20 to 80 °C and the activation energy for crystallization to be 0.23-0.30 eV as the film thickness varies from infinity to 200 A.

EPR Study of Ni2+-Vacancy Dipoles in LiCl Crystals

The paramagnetic resonance spectra of Ni 2+ in LiCl have been studied at 9 GHz. Two kinds of Ni 2+ centers associated with positive ion vacancy in their nearest or next nearest neighbour position are observed. Their spin Hamiltonian parameters are determined to be g x =2.27±0.04, g y =2.26±0.02, g z =2.31±0.01, | D |=0.564±0.002 cm -1 , | E |=0.080±0.002 cm -1 , and g // =2.360±0.005, g ⊥ =2.30±0.05, | D |=3.1±0.3 cm -1 and | E |≃0.0 cm -1 . The Ni 2+ -vacancy dipoles aggregated to form clusters and the isolated dipoles decayed in number. The decay constant of third order rate process is about 1.2×10 5 h -1 (mole fraction) -2 at room temperature. The EPR line width depends upon the crystal orientation. Interaction between near neighbour dipoles contributed to this anisotropic line width.

Electron Paramagnetic Resonance Studies of Mn2+ in Calcium-Doped NaCl

The decay process of Mn2+-vacancy dipoles in NaCl crystals have been studied at room temperature by the EPR method. The co-doped Ca2+ ions were effective in quickening the decay of these dipoles. It was shown that the decay rate was controlled only by the concentration of Ca2+, when the concentration of Ca2+ was larger than that of Mn2+.

Crystallization of Amorphous Sb1-xBix ( x ≤0.2) Films

A study is made of the crystallization in amorphous films of Sb1-xBix (x≤0.2) evaporated on a glass substrate. The crystal growth in films of thickness 70–500 A is directly observed through an optical microscope. The substrate is maintained between 20°C and 60°C. With the increase in x the crystallization thickness and the growth rate extrapolated to the infinite thickness decrease. The activation energy for crystallization seems not to depend on x but has a tendency to increase with the decrease in film thickness.

Ferromagnetic Resonance in Thin Films of the CrTe_ Sb_x System

A study is made of the magnetic properties of polycrystalline films of CrTe 1- x Sb x (0≦ x ≦0.4) through ferromagnetic resonance in the temperature range from liquid nitrogen temperature to room temperature. The observation of spin wave resonance is disturbed because of the broadening of the resonance lines unless x <0.3 or the temperature is far below the Curie temperature T c . The exchange coupling constant A in CrTe film is evaluated to be 0.37×10 -6 erg/cm at 77 K. The value of A decreases gradually as T c is approached or x increases. The dependence of A on temperature is generally consistent with that for Co metal given by Tannenwald and Weber or Cu-Ni alloys by Nose from spin wave resonance. The g -factor is nearly constant at low temperatures but increases rather abruptly as T c is approached. This behavior of g is explained on the basis of two layer-sublattices with a canted spin structure.

Ferromagnetic Resonance in Thin Films of the System MnSb–CrSb

A study is made on magnetic properties of thin films of Mn 1- x Cr x Sb(0≦ x ≦0.6) through ferromagnetic resonance. The films are deposited on plates of cover glass or rock salt to be 400 A to 3000 A in thickness. The spin wave resonance is observable at room temperature only when x ≤0.5. All the values of exchange coupling constant A , g -factor g and stress field 3λσ/ M decrease with the increase of x . Dependence of g and A on x are reasonably explicable on the basis of a canted spin structure where the spin axis lying within a ferromagnetic (001) layer is canted with that in the adjacent layers.