Conference On Molecules to Materials: ICMM2006

EUROMAR2006
Home | Sections 2 & 3 | Section 3 cntd & Section 4 | Section 4 cntd Figs6-9 | Section 5 ; References | EUROMAR2006 | An Abstract for the after-effects of an HR PMR study in Solids | Details of the particulars of particiaption in ICMM2006

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For an elaboration on the intramolecular aspects of induced fileds (measured as Chemical shifts) Click on Link: http://www.geocities.com/amudhan20012000/ismar_ca98.html

Following is the TEXT of Abstract 'Reuploaded' on 30th May 2006 for consideration to organizing committee EUROMAR2006; 16-21 July 2006; York, U.K.
 

SHAPE DEPENDENT FIELD INHOMOGENEITY OF HOMOGENEOUS SPECIMEN: CONSEQUENCES IN HR PMR IN SOLIDS


S.Aravamudhan


Department of Chemistry, North Eastern Hill University, PO NEHU Campus, Mawkynroh Umshing, East Khasi Hills District, Shillong, 793022, Meghalaya, INDIA


Magnetization within a material is inhomogeneous for specimen of shapes other than the regular ellipsoids. While discussing the demagnetization effects in a (homogeneously) magnetized sample, it becomes necessary to describe the hypothetical Lorentz sphere (Inner Volume Element: I.V.E.) around a specific site. This has brought in a compulsion that for HR PMR in solids a spherical outer shape for the specimen must be ensured for the possibility that the induced field at a specific site due to bulk susceptibility is zero1. The material within the IVE is effectively absent (a cavity) if the contributions of the molecules within this IVE is calculated independently and taken into account finally. Similarly, if the outer macro shape and the inner [IVE] shape are both ellipsoids and with same ellipticity, then the induced field within the inner element can be zero as much as for the spherically shaped sample specimen. Moreover, it has been found that the contribution from the neighboring molecules within the ellipsoidal IVE can be the same as the spherical IVE2.  For shapes other than ellipsoids, since the magnetization would be inhomogeneous within the sample, calculating contributions at one representative point within the sample would not be enough. Thus, it would be necessary to calculate the induced fields at every one of the points of interest independent of the other points. Even for shapes other than ellipsoidal, if the shape is describable as regular, then an IVE can be carved out with the same shape, and, proportionate shape factors. However, defining a demagnetization factor in such cases, even when it becomes possible, is associated with limitations. Because a simple summation procedure for calculating demagnetization factors is now known3 it seems it would be possible to consider the case of such inhomogeneously magnetized specimen with much better ease and to use the results with better confidence4. If the requirement of single crystal spheres could become less stringent in HR PMR studies in solids then the technique can be applied with much less constraints.

1. http://nehuacin.tripod.com/pre_euromar_compilation/                                

2. http://www.geocities.com/saravamudhan1944/eenc_ampere_lille.html

3. http://saravamudhan.tripod.com/

4. http://nehuacin.tripod.com/id3.html 

 


CLICK HERE  to view acceptance of Abstract for presentation at EUROMAR2006
These pre-euromar efforts have resulted in the "Euromar-onset" as it continues in this linked page

Link-1 Demagnetization Factors for General Ellipsoids J.Appl.Phys.,Vol.70 (6),pages 2911-2914,(1991)
Link-2 Demagnetization Factors for Rectangular Ferromagnetic Prisms J.Appl.Phys.,Vol.83 (6),pages 3432-3434,(1998)
The contents of the four sheets in Table-1 below can also be found in Sheet-7 to Sheet-10 (with added annotations and numerical estimates) at  http://www.geocities.com/inboxnehu_sa/nmrs2005_icmrbs.html. This poster site also has materials to substantiate the advantages of the summation procedure over the integration methods using elliptic integrals
Some details of methods, strategies and procedures
CLICK on each of the images below to display them in full size view

TABLE-1 below consists of 4 scanned images illustrating the simple summation procedure for calculating induced fields and demagnetization factors. The illustration is for macroscopic spherical shapes of specimen and for the ellipsoidal shapes appropriate analytical equations for the outer surface should be used to calculate the radius vector from the surface of the inner spherical cavity to the ellipsoidal outer surface of the specimen
Also visit webpage:  http://www.geocities.com/amudhan20012000/Confview.html from where the four scanned transparency sheets (Sheet-1 to Sheet4) have been extracted
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TABLE-2 below has additional illustartions for the matter covered in Table-1 above
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TABLE-3 below contains 5 pictures illustrations for the situation of shape dependent inhomogeneous magnetization of homgeneous specimen
Extracted from the poster materials at
 http://nehuacin.tripod.com/id3.html
CLICK on This picture to display full view for clarity and legibility CLICK HERE for particulars on the participation in 2nd Alpine Conference on SSNMR CLICK on This picture to display full view for clarity and legibility CLICK on This picture to display full view for clarity and legibility
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Click on the link below to display a webpage with links to contributions to events during July 2005 to February 2006. http://saravamudhan.tripod.com/id12.html#BOTTOM

 

 

The contents of pages: index, id1, id2, id3, & id4 of this ite contain the text of the
Full Paper appearing in the Proceedings of ICMM2006 March 3-6, 2006
Section on Materials for the Furure page 13-18; Article #2.3
 
The contents of page id5 is the Abstract for EPISTEME-2
 
The contents of page id6 is on EUROMAR2006