Total visitors:2,464 since 25-05-04

Indian Journal of Pure and Applied Physics

 

 

 ISSN: 0019-5596

CODEN: IJOPAU 42 (5) 309-382

Volume 42

Number 5

May 2004

 

 

CONTENTS

 

Atomic and Molecular Physics

 

FTIR, FT-Raman spectral analysis and normal coordinate calculations of 2-hydroxy-3 methoxybenzaldehyde thiosemicarbozone

313

V Krishnakumar* & V Balachandran

 

EDXRF: A non-destructive technique for multi-elemental analysis of coins                                                             

    319

P K Nayak, T R Rautray & V Vijayan*

 

 

ESR and thermoluminescence studies of bismuth doped calcium sulphide phosphors                                           

 323

Manoj Tiwari*, Vijay Singh, T K Gundu Rao & S J Dhoble

 

 

Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics and Fluid Dynamics

 

 

Realization of holographic optics based interferometer for study of phase objects                                                         

326

A K Aggarwal*, Sushil K Kaura, D P Chhachhia & A K Sharma

 

 

Optical refractive index from ultrasonic velocity in binary liquid mixtures                                                                

334

S Durai* & P Ramadoss

 

 

Ultrasonic behaviour of binary liquid mixtures of 1-bromopropane with cyclohexane and benzene                

338

S S Yadava* & Aniruddh Yadav

 

 

Current-mode universal filter using current feedback amplifiers                                                                                      

375

N A Shah*, M F Rather & S Z Iqbal

 

 

Condensed Matter: Structure, Mechanical and Thermal Properties

 

 

Temperature and frequency dependence of width in sodium potassium niobate mixed system                      341

341

Manish Uniyal, S C Bhatt, R Bhandari, M S Ramachandra Rao, R P Pant & B S Semwal*

 

 

Pressure – volume temperature (P-V-T) relationship for NaCl crystal                                             

347

D C Joshi, A P Gupta* & S Singh

 

 

Transition temperature for 4He liquid adsorbed in disordered media  

351

W T Sakwa, K M Khanna*, M Mueni, S Rotich & P K Torongey

 

Four – level approximation in disordered medium

355

W T Sakwa, K M Khanna*, M Mueni, S Rotich & P K Torongey

 

Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties

 

 

Interfacial reaction and surface morphology of Pd/Re contact schemes to p-type GaN                                                

361

V Rajagopal Reddy, C K Ramesh & P Narasimha Reddy*

 

 

Magnetic behaviour of nano-particles of Ni0.3Co0.5Fe2O4 prepared using two different routes                                     366

366

Subhash Chander*, Bipin K Srivastava & Anjali Krishnamurthy

 

 

Creep activation energy of flow process in Sb0.2 Bi1.8Te3 single crystals                                                              

371

P H Soni*, C F Desai & S R Bhavsar

 

 

 

*The corresponding author has been indicated by (*) marks in case of papers

with more than one author

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 42, May 2004, pp 313-318

 

FTIR, FT-Raman spectral analysis and normal coordinate calculations of
2-hydroxy-3-methoxybenzaldehyde thiosemicarbozone

V Krishnakumar & V Balachandran*

 

The normal coordinate analysis of 2-hydroxy-3-methoxybenzaldehyde thiosemicarbozone has been carried out by using a modified Urey-Bradley Force Field. The calculated frequencies were obtained by considering the interaction between non-neighboring stretching and bending vibrations and by introducing an appropriate set of internal coordinates in the course of calculations.  All the functional modes of vibrations are assigned and discussed in detail.

 

[Key words: Normal coordinate analysis, Vibrational spectra, Hydroxy methoxybenzaldehyde thiosemicarbozone, Potential energy]

IPC Code: G 01J 3/44

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 42, May 2004, pp 319-322

 

EDXRF: A non-destructive technique for multi-elemental analysis of coins

P K Nayak, T R Rautray & V Vijayan*

 

Eleven silver and twenty-five copper coins of British rule (1857-1947 A.D.) have been studied and their elemental compositions have been estimated using non-destructive and simultaneous multi-elemental EDXRF technique in order to verify the effectiveness of this technique for analysis of coins on routine basis. The computer code AXIL was employed to obtain the elemental concentrations from the EDXRF spectra. The obtained results are presented.

 

[Keywords: Non-destructive analysis, coins, energy dispersive X-ray fluorescence (EDXRF), chemical composition, archaeological materials]

IPC Code: G 01 N 21/00

 

 

 

Indian Journal of Pure & Applied Physics

 Vol. 42, May 2004, pp 323-325

 

ESR and thermoluminescence studies of bismuth doped calcium sulphide phosphors

Manoj Tiwari , Vijay Singh, T K Gundu Rao# & S J Dhoble$

 

Thermally stimulated luminescence (TSL) and electron spin resonance (ESR) studies were carried out on bismuth doped CaS phosphor synthesized by using solid-state reaction technique. The defect centers formed in CaS:Bi   were studied using the technique of electron spin resonance. The thermoluminescence glow curve shows two peaks at about 400 and 505K. Irradiated CaS:Bi exhibits  ESR lines due to defect centers. Thermal annealing behaviour of the phosphor indicates that one of the defect centres correlates with the TSL peaks at 400 and 505K. The center is characterized by an isotropic g-value of 2.0034 and is assigned to a F+ center.

 

[Keywords: Electron spin resonance, Thermoluminescence, CaS phosphor, Defect centre]

IPC Code: F 21 K 2/04

 

 

 

Indian Journal of Pure & Applied Physics

 Vol. 42, May 2004, pp 326-333

 

Realization of holographic optics based interferometer for study of phase objects

*A K Aggarwal, Sushil K Kaura, D P Chhachhia  &  A K Sharma

 

The paper describes different configurations for realization of a simple, compact and robust holographic optics based interferometer, which makes use of minimal bulk optical components. The optical arrangements in the proposed interferometer set-ups involve a very simple alignment procedure and conventional holographic recording material is used in the formation of holographic optical elements. Recording schemes for the formation of holographic optical elements and the related techniques for the realisation of three different interferometer set-ups along-with the experimental results have been presented. The proposed interferometer set-ups are quite suitable for performing optical test studies on phase (transparent) objects in real time.

 

[Key words: Optical interferometry, Holographic optical elements, Phase visualization, Optical testing techniques]

IPC Code: G 01 B 9/026

 

 

 

Indian Journal of Pure & Applied Physics

 Vol. 42, May 2004, pp 334-337

 

Optical refractive index from ultrasonic velocity in binary liquid mixtures

S Durai & P Ramadoss

 

A new empirical relation connecting the optical refractive index and the ultrasonic velocity has been tried in the case of solutions (Durai S & Ramadoss P, Acta Acustica, 89 (2003) 173). In this paper the same is extended to four binary liquid mixture systems, making use of the experimental data available. The results are satisfactory.  Jacobson’s free length (Lf ) and mean free path (l) play significant roles. Further Debye temperature a property of solid like behaviour of liquids is calculated for the systems and the results are analyzed.

 

[Keywords: Optical refractive index, Binary liquid, Ultrasonic velocity, Debye temperature]

IPC Code: G 01 S 15/00

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 42, May 2004, pp 338-340

 

Ultrasonic behaviour of binary liquid mixtures of
1-bromopropane with cyclohexane and benzene

S S Yadava & Aniruddh Yadav

 

Ultrasound velocity and densities of the binary mixture of 1-bromo-propane with cyclohexane and benzene over the whole composition range at 308.15 K have been measured. The adiabatic compressibilities and deviation from ideal adiabatic compressibilities have been evaluated. The value of ultrasound velocity decreases and comes to a minimum and then increases as the mole fraction of 1-bromopropane increases in the binary mixture with cyclohexane and benzene. The variation of adiabatic compressibilities with mole fraction is sigmoid for both the mixture. The excess adiabatic compressibility of binary mixture with cyclohexane is positive at all concentrations, while it is negative at lower mole fractions of 1-bromopropane of the binary mixture with benzene and positive at higher mole fractions. The results are discussed in terms of molecular interactions.

 

[Keywords: Ultrasonics, Binary liquid mixtures, 1-bromopropane]

IPC Code: B01J 19/10

 

 

 

 

Indian Journal of Pure & Applied Physics

 Vol. 42, May 2004, pp 375-377

 

Current-mode universal filter using current feedback amplifiers

N A Shah, M F Rather & S Z Iqbal

 

A new current-mode (CM) universal filter based on and employing three each of non-inverting current feedback amplifiers (CFAs), capacitors, and resistors is presented. Without changing the circuit topology the output currents simultaneously supports lowpass (LP), highpass (HP), and bandpass (BP) responses. The notch (BR) and allpass (AP) filtering functions can be achieved by connecting the appropriate nodes without requiring the use of additional components. The proposed circuit enjoys low passive sensitivities and orthogonal tuning of the parameters natural frequency,w0 and quality factor, Q. Personal computer-simulation programme with integrated circuit emphasis (PSPICE) simulated results agree well with calculated values.

 

[Keywords: Current-mode filters, Universal filters]

IPC Code: H 03 H 7/075

 

 

 

Indian Journal of Pure & Applied Physics

 Vol. 42, May 2004, pp 341-346

 

Temperature and frequency dependence of width in
sodium potassium niobate mixed system

Manish Uniyal, S C Bhatt, R Bhandari, M S Ramchandra Rao#, R P Pant* & B S Semwal

 

Considering a quadratic anharmonic model Hamiltonian and using double time temperature dependent Green's function method and Dyson’s equation treatment, expressions for the width in the frequency response for mixed perovskite type ferroelectrics have been obtained. Using the experimentally observed dielectric constant and loss tangent for Na1-xKxNbO3 [where x = 0, 0.4, 0.5], the temperature dependence of soft mode width in these samples at 10 and 100 kHz has been calculated. Anomaly has been observed in the behaviour of soft mode width, near the transition temperatures in these compounds.

 

[Keywords: Ferroelectricity, Piezoelectricity, Soft mode frequency]

IPC Code: H 01 L 41/00

 

 

 

 

Indian Journal of Pure & Applied Physics

 Vol. 42, May 2004, pp 347-350

 

Pressure-volume-temperature (P-V-T) relationship
for NaCl crystal

D C Joshi, A P Gupta & S Singh

 

A method for determining the compression data (V/V0) at simultaneously elevated temperature and pressure up to a pressure of 35 kbar and a temperature of 773K has been developed. This method is based on the Chopelas Boehler approximation for variation of the Anderson-Gruneisen parameter dT with the change in compression. The calculated values are found to be in good agreement with the experimental data.

 

[Keywords: NaCl crystal, Pressure-volume-temperature, Chopelas Boehler approximation]

IPC Code: G06

 

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 42, May 2004, pp 351-354

 

Transition temperature for 4He liquid adsorbed in disordered media

W T Sakwa, K M Khanna, M Mueni, S Rotich & P K Torongey

 

For pure 4He liquid the superfluid fraction starts having a finite value at and below the l-transition temperature 2.176K, whereas for 4He in a disordered media the superfluid fraction starts having a finite value at 2.168K, a temperature that is lower compared to the temperature at which superfluidity appears in pure 4He. Relations for transition temperatures for both cases that are in agreement with experimental values have been obtained. Adsorption, which normally leads to a decrease in the degrees of freedom, consequently results in a release of heat, which destroys superfluidity. Hence for the liquid 4He flowing into a disordered medium, the transition temperature is expected to be lower.

 

[Keywords: Transition temperature, Superfluid, Disordered media]

IPC Code: G 01 D

 

 

 

 

Indian Journal of Pure & Applied Physics

 Vol. 42, May 2004, pp 355-360

 

Four-level approximation in disordered medium

W T Sakwa, K M Khanna, M Mueni, S Rotich  & P K Torongey

 

The adsorption of superfluid 4He into a disordered medium, the disappearance of superfluidity due to adsorption, and the subsequent appearance of superfluidity when more 4He flows into the disordered medium have been described by the four-level approximation. The adsorption of superfluid 4He into a disordered medium depletes the ZMS as the particles shift to higher excited levels resulting in ‘four-level approximation’. Superfluidity reappears on further adsorption but at a lower temperature implying that the Tc value of a four-level system should be lower than the Tc value for a three-level system, which is in agreement with the experimental observations.

 

[Keyword: Superfluidity, Disordered medium, Four-level approximation]

IPC Code: H01B 12/00

 

 

 

 

Indian Journal of Pure & Applied Physics

 Vol. 42, May 2004, pp 361-365

 

Interfacial reaction and surface morphology of Pd/Re contact schemes to p-type GaN

V Rajagopal Reddy & C K Ramesh Hassan and P Narasimha Reddy D

 

The interfacial reactions between the Pd (20 nm) / Re (25 nm) contacts and p-GaN (1.13×1017cm-3) have been investigated using glancing angle XRD and Auger depth profiling. The samples are annealed at temperatures of 550 ºC and 650 ºC for 1 min in a nitrogen ambient. The I-V measurements show that the as-deposited sample is ohmic with a contact resistance of 1.4×10-3 W cm2. However, the annealing of the sample at 550 ºC results in much better ohmic behaviour with a specific contact resistance of 8.7×10-4 W cm2. Further, increase in annealing temperature (650 ºC) causes the degradation of the ohmic property. Based on AES and XRD results, the formation of Ga-Pd reaction phases results in the generation of Ga vacancies at the GaN surface region, which plays a role in reducing contact resistivity. The AFM results show that the surface morphology of the as-deposited contact is fairly smooth (with a rms roughness of 1.7 nm) and when annealed at 550 °C, contact has become somewhat degraded with a root-mean-square roughness of 6.5 nm.

 

[Keywords:  interfacial reaction, Pd/Re contacts, surface morphology, glancing angle XRD, Auger depth profiling]

IPC Code: H 01 C 10/00

 

 

 

Indian Journal of Pure & Applied Physics

 Vol. 42, May 2004, pp 366-370

 

Magnetic behaviour of nano-particles of Ni0.5Co0.5Fe2O4 prepared
using two different routes

Subhash Chander, Bipin K Srivastava & Anjali Krishnamurthy

 

Literature reports on bulk sample of the ferrite Ni0.5Co0.5Fe2O4 confirm a complete inverse spinel structure. On site occupancy and magnetic anisotropy on nano-particle samples of the titled ferrite prepared using two different routes – a wet chemical co-precipitation process and sol-gel method have been studied.  Estimated   average particle sizes of the two samples (referred to as NCWET and NCSOL) are ~75Å and ~190Å respectively. Small angle neutron scattering measurements made on the fluid sample comprising the sample prepared by wet chemical process gives median size ~77Å with standard deviation σ = 0.60.  Mössbauer studies at 300K show that the two ferrite samples maintain inverse spinel structure even in nano-crystalline state. Magnetization and Mössbauer measurements show that part of the sample in both the cases is in superparamagnetic state. Magnetic anisotropy is larger in the nano-particle state and surface spin disorder also contributes to this.

 

[Keywords: Magnetic anisotropy, Nano-particles, Spinel ferrites]

IPC Code: H 01 F 41/30

 

 

 

Indian Journal of Pure & Applied Physics

 Vol. 42, May 2004, pp 371-374

 

Creep activation energy of flow process in Sb0.2 Bi1.8Te3 single crystals

P H Soni, C F Desai & S R Bhavsar

 

Temperature dependence of the Vickers microhardness of Sb0.2 Bi1.8Te3 single crystals has been studied. Loading time dependence of microhardness at different temperatures has been used for creep study in the temperature range 303-373 K. The activation energy for indentation creep of the crystals has been evaluated.

 

[Keywords: Vickers microhardness; Cleavage surface; Creep; Activation energy]

IPC Code: G 01 N 3/18