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Indian Journal of Engineering & Materials Sciences

 

 

  

ISSN : 0971-4588

 

CODEN : IEMSEW

VOLUME 11

NUMBER 4

AUGUST 2004

  

 Special Issue on

Recent Advances in Nanotechnology of Magnetic Fluids

 

 CONTENTS

Ferrofluids, sol-gel method and materials for optical applications

D Jamon, D Zins, H Roux, F Royer, V Cabuil, C Bovier & J J Rousseau

237

[IPC Code: Int. Cl.7 H01F 1/44 ]

 

 

 

New commercial trends of nanostructured ferrofluids

241

K Raj, B Moskowitz & S Tsuda

 

[IPC Code: Int. Cl.7 H01F 41/30]

 

 

 

Models for microrheology of complex magnetic fluids

253

Yu L Raikher & V V Rusakov

 

 [IPC Code: Int. Cl. H01F 1/44]

 

 

 

Characterization of transformer oil based magnetic fluid

262

Kinnari Parekh & R V Upadhyay

 

[IPC Code: Int. Cl.7 H01L 27/00]

 

 

 

Synthesis and characterization of ferrofluid-conducting polymer composite

267

R P Pant, S K Dhawan, D K Suri , Manju Arora , S K Gupta , M Koneracka, P Kopcansky & M Timko

 

[IPC Code: Int. Cl.7 H01F 1/44]

 

 

 

Structural transitions in thermotropic ferronematics

271

P Kopčanský, I Potočová, M Koneracká, M Timko, J Jadzyn, G Czechowski & A G M Jansen

 

[IPC Code: Int. Cl.7 C09K 19/00]

 

 

 

Complex characterization of physiology solution based magnetic fluid

276

M Timko, M Koneracká, P Kopčanský, Z Tomori, L Vékas, A Józefczak, A Skumiel, A Radenovic, G Dietler, E Bystrenová & M Lita

 

[IPC Code: Int. Cl.7 H01F 1/44]

 

 

 

Simulations of thermo-magnetic convection in an annulus between two concentric cylinders

283

T Tynjälä & J Ritvanen

 

[IPC Code: Int. Cl.7 H01F 1/44]

 

Effect of preparation on magnetic properties of Mn-Zn ferrite

289

G Vaidyanathan, R Arulmurugan, S D Likhite, M R Anantharaman,  Milind Vaidya, S Sendhilnathan & N D Senthilram

 

[IPC Code: Int. Cl.7 H01F 10/20]

 

Investigation of new magnetocontrolled polymer materials

295

L V Nikitin

 

[IPC Code: Int. Cl.7 G01R]

 

 

 

Rheology of transformer oil based ferrofluids

301

Rajesh Patel, Kinnari Parekh, R V Upadhyay & R V Mehta

[IPC Code: Int. Cl.7 H01F 1/44]

 

 

 

Variable temperature electron paramagnetic resonance investigations of an ionic ferrofluid

305

S K Gupta, R P Pant & Manju Arora

 

[IPC Code: Int. Cl.7 H01F 1/44]

 

 

 

Magnetic action on convection and heat transfer in ferrofluid

309

A A Bozhko & G F Putin

 

[IPC Code: Int. Cl.7 H05B 3/00]

 

 

 

Electron microscopy and diffraction analysis of nano-structured prussian blue thin films

315

A K Srivastava, Ram Kishore, Swati & S A Agnihotry

 

[IPC Code: Int. Cl.7 H01F 10/32]

 

 

 

Nanocrystalline magnetic alloy thin films

319

S C K Misra, Prafull Mathur, R P Pant & Anil K Gupta

 

[IPC Code: Int. Cl.7 H01F 10/12]

 

 

 

First century of colloid magneto-optics

323

P C Scholten

 

[IPC Code: Int. Cl.7 B01J]

 

 

 

Ferroconvection induced by point heat source

331

R Sekar, G Vaidyanathan & R Vasanthakumari

 

[IPC Code: Int. Cl.7 H01F 1/44]

 

 

 

Investigation on magnetic fluids as lubricant

338

Jan Burcan, Ewa Burcan-Piotrowicz & Anna Sławińska

 

[IPC Code: Int. Cl.7 F16N 15/00]

 

 

 

Verwey type transition in nano-particle spinel ferrite Fe2.2Co0.8O4

343

Subhash Chander, Anjali Krishnamurthy, Bipin K Srivastava, Ajay Gupta & Arun Kumar Nigam

 

[IPC Code: Int. Cl.7 H01F 10/20]

 

 

 

Fabrication of an a.c. susceptometer to study the magnetic susceptibility in some ferro/-ferrimagnetic materials/fluids

 

349

Kalpesh H Jani, R V Upadhyay & R V Mehta

 

[IPC Code: Int. Cl.7 H01F 1/44]

 

 

Preparation and characterization of vacuum deposited magnetic polyaniline thin films

353

Prafull Mathur, S C K Misra, Ram Kishore, U C Upreti & J L Pandey

 

[IPC Code: Int. Cl.7 H01F 10/26]

 

 

Advancement in the field of magnetic fluids for drug discovery, medicine and biotechnology

358

Z M Saiyed, S D Telang & C N Ramchand

 

[IPC Code: Int. Cl.7 H01F 1/44]

 

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 237-240

 

Ferrofluids, sol-gel method and materials for optical applications

D Jamon, D Zins, H Roux, F Royer, V Cabuil, C Bovier & J J Rousseau

 

This paper describes how ferrofluids can be used to develop new composite materials for optical applications. Ferrofluids are interesting materials for optics. Isotropic in a zero magnetic field, these hybrid media exhibit optical anisotropies under an applied magnetic field. For optical applications, the drawback of ferrofluids is their liquid state. It is shown that by using sol-gel method new solid material can be achieved. Moreover, permanent linear birefringence has been obtained for sol-gel samples synthesized under an applied field. This anisotropy can be adjusted. Doped sol-gel structures keep the same magneto-induced circular anisotropy of the ferrofluid but no permanent effect is achieved.

IPC Code: Int. Cl.7 H01F 1/44

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 241-252

 

 New commercial trends of nanostructured ferrofluids

K Raj, B Moskowitz & S Tsuda

 

In the realm of nanotech materials, ferrofluids are unique in that their constituents are both liquid and solid. True microsystems based on hydrodynamic principles of ferrofluids may still be some years away. However, ferrofluids are already contributing to nanotechnology, first as components of microproducts and second by their utilization in processes engaged in fabrication of nanostructured materials. This paper focuses on applications of ferrofluids, which are related to the drive towards the new technology.

 

IPC Code: Int. Cl.7 H 01F 41/30

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 253-261

 

Models for microrheology of complex magnetic fluids

Yu L Raikher & V V  Rusakov

 

A review of some aspects of orientational magnetodynamics of viscoelastic magnetic fluids and ferrogels is given. As an archetypal theoretical model we use an assembly of non-interacting dipolar Brownian nanoparticles embedded in and coupled to a matrix that possesses either a dynamic (Maxwellian) or a weak equilibrium (Hookean) elasticity or both. With regard to their magnetic properties, the particles are assumed to be rigid dipoles. In the mechanical aspect the particles are taken to be two-dimensional, i.e., are modeled by disks, either inertial or inertia-less. Two types of dissipative interaction between a particle and its environment—a simple Stokes viscous friction and a friction with a simple exponential memory (like in a Maxwellian fluid)—are analyzed. Using the linear response approach we find the equilibrium correlation functions and the dynamic magnetic susceptibilities of the media. For the case of inertia-less particles the kinetic equation of rotary diffusion is derived and certain peculiarities in its properties are discussed.

IPC Code: Int. Cl.7 H 01F 1/44

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 262-266

 

Characterization of transformer oil based magnetic fluid

 Kinnari Parekh & R V Upadhyay

 

In the present paper two different magnetic fluids synthesized earlier with transformer oil as carrier liquid are characterized. The magnetic properties of these fluids are studied using viscometry, magnetometer and Quincke’s technique. The properties of the magnetic fluid are compared with those of the pure transformer oil and the results are discussed.

 

IPC Code: Int. Cl.7 H 01L 27/00

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 267-270

 

Synthesis and characterization of ferrofluid-conducting polymer composite

R P Pant, S K Dhawan , D K Suri, Manju Arora , S K Gupta , M Koneracka,

P Kopcansky & M Timko

 

Composites of ferrofluid-conducting polymer system have been prepared by co-precipitation and doping process. The prepared samples have been mainly characterized by FTIR, TEM, SEM, X-ray and EPR techniques. Relaxation behavior at room and liquid nitrogen temperatures, shape and size distribution of the composite gradients, sample crystallinity and the functional group attachment have been investigated. A probable schematic representation of composite formation has been described. It is observed that ferrofluid composite with saturation magnetization , Ms = 90 gauss, has electrical conductivity of the order of s = 1.0 ´ 10-3 W-1cm-1 which remains stable in gradient magnetic field.

IPC Code: Int. Cl.7 H01F 1/44

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 271-275

 

Structural transitions in thermotropic ferronematics

 P Kopčanský, I Potočová, M Koneracká, M Timko, J Jadzyn, G Czechowski & A G M Jansen

 

The structural instabilities in ferronematics based on different types of liquid crystals, exposed to electric or magnetic fields oriented perpendicular (Fredericksz transition) and parallel to the initial director, were studied within the Burylov and Raikher’s theory. Using the capacitance measurements the critical electric (magnetic) fields EFN (BFN), corresponding to the Fredericksz transition, and fields Emax, (Bmax,), at which the initial perpendicularity between director  and magnetic moment  breaks-down in field parallel to the initial director, were found. These values were then used for the estimation of the surface density of the anchoring energy W of liquid crystal molecules on the magnetic particle surface.

 

IPC Code: Int. Cl.7 C09K 19/00

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 276-282

 

Complex characterization of physiology solution based magnetic fluid

M Timko, M Koneracká, P Kopčanský, Z Tomori, L Vékas, A Józefczak, A Skumiel,
A Radenovicd, G Dietlerd, E Bystrenováa,d & M Lita
e

 

Atomic force microscopy (AFM), transmission electron microscopy (TEM) and magnetization measurements by vibrating sample magnetometer (VSM) were used for estimation and comparison of size of magnetite particles in physiology solution based magnetic fluid (MF). The mean particle diameter values were 7.6 nm, 9.3 nm and 10.6 obtained by AFM, VSM and TEM, respectively. For the analysis of AFM pictures the more precise method was developed where the particle size was calculated as the geometrical mean of sizes in all three dimensions. The structural stability of prepared MF was affirmed by the ultrasonic measurements.

 

IPC Code: Int. Cl.7 H01F 1/44

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 283-288

 

Simulations of thermo-magnetic convection in an annulus between two concentric cylinders

T Tynjälä & J Ritvanen

 

In this paper the thermo-magnetic convection of a magnetic fluid held between two vertical concentric cylinders is studied. Three-dimensional computer simulations of thermo-magnetic convection have been conducted under an azimuthal magnetic field, when the inner cylinder is kept at a higher temperature than the peripheral one. Simulations have been carried out both in the absence and in the presence of gravity. In the absence of gravity, the problem will be analogous to the classical Rayleigh-Bernard instability in a radial gravitation field. The objective of this study is to investigate the combined effects of magnetic and buoyancy driven convection. In the absence of gravity the simulations revealed the expected flow pattern consisting of counter rotating convection cells with diameter equal to the thickness of the fluid layer. When the gravity is introduced, the case may become unsteady consisting of cells drifting upward. For small gravitational Rayleigh numbers introduction of magnetic field gradient may stabilize the flow. The onset of instability depends on the magnetic and the gravitational Rayleigh numbers and their ratio, radius and aspect ratios of the cylinders as well as on the fluid properties.

 

IPC Code: Int. Cl.7 H 01F 1/44

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 289-294

 

Effect of preparation on magnetic properties of Mn-Zn ferrite

 G Vaidyanathan, R Arulmurugan, S D Likhite, M R Anantharaman,
Milind Vaidya, S Sendhilnathan & N D Senthilram

 

Mixed ferrites belonging to the type Mn0.9Zn0.1Fe2O4 have been prepared by the double sintering method and by the chemical co-precipitation for comparing their magnetic properties. Sintered and precipitated ferrites exhibit different characteristics, especially in their magnetic properties like magnetization (Ms), coercive field (Hc) and Curie temperature (Tc). The sintered particles were size reduced in order to compare with the nanosized co-precipitated particles. The effect of grinding has also been studied. Particles have been collected at regular intervals of grinding and their properties have been studied. The increase in the coercive field has been recorded by a hysteresis curve tracer confirming size reduction. X-ray diffraction studies confirmed the structure and consequent size reduction.

IPC Code: Int. Cl.7 H01F 10/20

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 295-300

 

Investigation of new magneto-controlled polymer materials

 L V Nikitin

 

New polymer magneto-controlled materials with a effect of a magnetic field influence on the shape, the elastic and viscous properties are discussed. It is shown that the application of a magnetic field leads to a large elongation of these materials (several hundred percents) and a considerable rise in the Young’s modulus and the viscosity of these materials. Samples prepared in the absence of magnetic field and in magnetic field applied during magneto-elastic curing are investigated.

 

IPC Code: Int. Cl.7 G 01R

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 301-304

 

Rheology of transformer oil based ferrofluids

 Rajesh Patel, Kinnari Parekh R V Upadhyay & R V Mehta

 

In the present study we report results of rheological properties of temperature sensitive transformer oil based ferrofluids as a function of external magnetic field and temperature. The field induced viscosity is analyzed using Shliomis model. The variation of magnetic moment and domain magnetization with temperature has been deduced from this measurement which agrees with the reported values deduced from magnetization technique.

 

IPC Code: Int. Cl.7 H01F 1/44

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 305-308

 

Variable temperature electron paramagnetic resonance investigations of an ionic ferrofluid

S K Gupta, R P Pant & Manju Arora

 

An aqueous based ionic ferrofluid has been studied by EPR spectroscopy technique from room temperature to liquid nitrogen temperature to detect the magnetic phase transitions and their variation at low temperatures. The line-width of EPR signal has been found to increase with decreasing temperature and this has been assigned to magnetic phase transition from ferromagnetic to a spin glass or cluster glass state mainly due to freezing of the carrier fluid. Line-width variation with temperature also suggests that bulk rotation mechanism is the dominant mode of relaxation. Any evidence of the presence of super-paramagnetism has not been observed.

 

IPC Code: Int. Cl.7 H01F 1/44

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 309-314

 

Magnetic action on convection and heat transfer in ferrofluid

 A A Bozhko & G F Putin

 

The interplay of buoyancy and thermo-magnetic convection mechanisms are investigated in a horizontal ferrofluid layer heated from one wide side and cooled from another in the presence of external uniform transversal magnetic field. The influence of gravitational settling of magnetic particles and their aggregates on heat transfer and convection instability is also considered. The ferro-colloids with different concentrations of magnetic phase are employed for the control of driving magnetic forces. It is shown that in concentrated colloid the driving forces prevail over suppress ones, but in weak concentrated colloid the gradients of density due to gravity sedimentation of particles overwhelm convection stirring. It is important that thermo-magnetic convection mechanism allows strengthening of heat transfer in ferrofluid three times.

 

IPC Code: Int. Cl.7 H05B 3/00

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 315-318

 

Electron microscopy and diffraction analysis of nano-structured prussian blue thin films

A K Srivastava, Ram Kishore, Swati & S A Agnihotry

 

Prussian blue (PB) thin films have been deposited galvanostatically on transparent conducting coated glass plates with a current density of 20 mA/cm2 using equivolume mixture of 10 mM FeCl3 and 10 mM K3Fe(CN)6 in 0.01 N HCl. During deposition the process conditions have been suitably varied to obtain electron beam transparent thin films. A transmission electron microscope has been extensively used to understand the microstructural features at nano-scale, evolved during deposition and the respective selected area electron diffraction patterns have also been studied to reveal amorphous and crystalline behaviour of nano-grains in the microstructure. A detailed characterization of these films illustrated that the films in general constituted of amorphous nano-grains (20-100 nm) with some regions consisting of crystalline phase in the microstructure. The fine details associated with structure and microstructure of PB thin films have been discussed and correlated with their electro-chromic properties

 

IPC Code: Int. Cl.7 H01F 10/32

 

 

  

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 319-322

 

Nanocrystalline magnetic alloy thin films

S C K Misra, Prafull Mathur, R P Pant & Anil K Gupta

 

In this communication the preparation and characterization of nanocrystalline magnetic thin films of Mn doped Zn-Te alloys, prepared on various types of substrates by vacuum deposition techniques have been described. This technology is completely dry and suitable for making nanocrystalline device quality magnetic films on a complicated structure and is preferred for its simplicity. These magnetic thin films can be used as excellent recording media for information storage and handling

 

IPC Code: Int. Cl.7  H01F 10/12

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 323-330

 

First century of colloid magneto-optics

P C Scholten

 

Starting with the first report of a magneto-optical effect in a colloid by Grove in 1845 and the unsuccessful search by Faraday, the various discoveries by Kerr, Majorana, Cotton and Mouton and others up to about 1940 are described. A survey of the development of the theoretical interpretation has as highlights Schmauss' idea of particle orientation, Cotton and Mouton realizing that thermal motion provided the opposing mechanism, and Langevin's statistical-mechanical treatment. This part ends with the expressions for the dichroism by Naik and Desai in 1964.

 

IPC Code: Int. Cl.7 B01J

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 331-337

 

 Ferroconvection induced by point heat source

R Sekar, G Vaidyanathan &  R Vasanthakumari

 

A mathematical model is proposed to study the onset of the free convection in ferrofluid at low Rayleigh number from an instantaneous point heat source. In this work, the leading term of series expansion of the dependent variable in terms of Rayleigh number is considered and is valid in small Rayleigh number regime only. The rate of heat generation is assumed to be not very high, so that Stoke’s flow approximation could be used. The flow field is explained by the streamlines at different times. In the absence of field, the results are compared for the thermal convection due to the instantaneous point heat source.

IPC Code: Int. Cl.7 H 01F 1/44

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 338-342

 

 Investigation on magnetic fluids as lubricant

Jan Burcan, Ewa Burcan-Piotrowicz & Anna Sławińska

 

Experimental data were obtained for the lubricated bearings of precision and fine mechanisms, operating in the conditions of boundary friction or, at best, of mixed friction. The use of magnetically active lubricant in the thrust bearing with the spinning point contact, where the spherical surface rotation in relation to the axially-symmetrical seat (spherical bowl or plane), makes the fluid film lubrication possible. It is possible because the addition of new potential field, that means magnetic field, changes the energetic state of equilibrium occurring in spinning friction of slides.

 

IPC Code: Int. Cl.7 F16N 15/00

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 343-348

 

Verwey type transition in nano-particle spinel ferrite Fe2.2Co0.8O4

 Subhash Chander, Anjali Krishnamurthy, Bipin K Srivastava, Ajay Gupta & Arun Kumar Nigam

 

Results are presented on magnetization and Mössbauer measurements on two multi-disperse nano-particle samples of Co substituted spinel ferrite Fe2.2Co0.8O4 with average particle sizes of ~ 50 Ǻ and ~ 80 Ǻ. In these nono-particle samples Co occupies the octahedral site B with ~ 60% preference. The 50 Ǻ average particle sized sample Co50 is largely in super-paramagnetic state at 300 K and its blocking temperature Tis ~ 260 K. 80 Ǻ average particle sized sample Co80 has its TB above 300 K. The two samples exhibit magnetic relaxation. Much smaller moments of the two samples than saturation magnetization for the bulk particle sample and a loop shift observed in M-H curves of Co50 recorded in zero field and field cooling modes are suggestive of spin disordered surfaces. The nano-particle sample Co80, of the ferrite Fe2.2Co0.8O4 which in its bulk particle state is known to have more than an order of magnitude higher magneto-crystalline anisotropy than Fe3O4, shows signature of a ‘Verwey’ type transition with enhanced magnetic anisotropy below ~ 90 K. Co50 does not show a ‘Verwey’ type transition. A weak hump in M-T curve at a lower temperature of ~ 50 K in Co50 is attributed to disordered spin freezing.

 

IPC Code: Int. Cl.7 H01F 10/20

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 349-352

 

Fabrication of an a.c. susceptometer to study the magnetic susceptibility in some ferro/ferrimagnetic materials/fluids

 Kalpesh H Jani, R V Upadhyay & R V Mehta

 

An a.c. susceptometer is fabricated to measure the a.c. susceptibility of variety of magnetic materials comprising magnetic fluids. The instrument is designed to work in the temperature range 77-300 K. It covers wide range of frequencies from 1 Hz to 5 kHz. The instrument is interfaced with a personal computer for data acquisition. A variety of magnetic samples have been characterized using the set-up.

 

IPC Code: Int. Cl.7  H 01F 1/44

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp. 353-357

 

Preparation and characterization of vacuum deposited magnetic polyaniline thin films

Prafull Mathur, S C K Misra, Ram Kishore, U C Upreti & J L Pandey

 

Vacuum deposited polyaniline thin films have been found to exhibit excellent magneto-optic properties. The vacuum deposited thin films of doped polyaniline have been prepared on various substrates and their optical, electrical and magnetic characterization carried out. The thin films prepared on different substrate show a variety of surface topography and magnetic domains in crystalline phase. The crystallinity is induced by the influence of substrate on which the film is deposited. This technology establishes the feasibility of preparation of high-density disc storage magnetic recording media using vacuum deposited thin films. The advantage of these films is their magnetization at lower magnetic fields.

 

IPC Code: Int. Cl.7 H01F 10/26

 

 

 

Indian Journal of Engineering & Materials Sciences

 Vol. 11, August 2004, pp.358-362

 

 Advancement in the field of magnetic fluids for drug discovery, medicine and biotechnology

 Z M Saiyed , S D Telang & C N Ramchand

 

Techniques based on magnetic separation have become increasingly popular among the biological community. Magnetic separation technique offers advantage in terms of subjecting, analyte to very little mechanical stress compared to other methods, they are rapid, often highly scalable, low cost and avoid use of hazardous toxic reagents. Techniques employing magnetism are more amenable to automation and miniaturization. This paper reviews the advancement made in the field of medicine, biotechnology and drug discovery using magnetic particles technology.

 

IPC Code: Int. Cl.7 H01F 1/44