Materials Matters

Vol 2. No. 1

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President's Journal

by Leslie J. Evelyn

Welcome! In this issue we have included articles on research projects, carried out at Alabama A&M University, that involve the use of ion beams to modify materials for both electronic the optical use. We have had to sacrifice detail to some degree to meet length constraints, but we hope that these omissions will not alter in any way your interpretation of what has been accomplished. You will also find a report on the participation of some of our students in the National Conference of Black Physics Students recently held in Atlanta, Georgia and also at the 11th International Conference on Ion Beam Analysis in Balatonfured, Hungary

On another note, the AAMU-MRS Chapter is collaborating with the AAMU-OSA Chapter to design joint social and educational activities that will encourage communication and technical information exchange among students, locally and nationally, across our disciplines to keep up with the latest research and development in our fields. We also hope to network with industry, government, and education sectors at the annual Technical and Business Exhibition and Symposium, May 10-11, 1994 at the Von Braun Civic Center, Huntsville, Alabama. We hope you find our latest issue interesting and stimulating. Enjoy!

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NEWS! NEWS! NEWS!

Newsletter

Our Editor unilaterally decided to have Materials Matters published twice a year rather than quarterly. Neither I (ALE) no Professor Ila (Faculty Advisor) have any objection to his decision, since EKW and I do most of our legwork for this newsletter with blessings ($) from our faculty advisors.

Student Visitor from France

We had Arnaud Crastes from Université Claude Bernaud, Lyon, France, as our guest student for July and August of 1993. Professor Paul Thevenard of Lyon advised him to perform hsi summer training with Prof. D. Ila at the Center for Irradiation of Materials at Alabama A&M University. Apparently he was so impressed with our hospitality and the mild summer weather of Alabama that he has recommended us to several of his colleagues and we may have two or three more visiting French students this summer (1994).

Travel to Hungary

Several of our colleagues attended the 11th International Conference on Ion Beam Analysis held on the shores of Lake Balaton in Hungary. The researchers from the Center for Irradiation of Materials at AAMU were the only representatives from Alabama. More info later on this issue.

Visiting Scientist from Brazilian Space Agency

Dr. Irajá Bandeira of the Brazilian Space Agency, INPE, visited AAMU during August and September 1993. He and our advisors submitted to NASA our first joint international proposal to process materials in zero gravity. Dr. Bandeira also chaired a symposium on zero gravity materials processing during the Seventh Alabama Materials Research Conference, which was held in September, 1993 at AAMU.

Travel to Buffalo, NY

Our Carbon research and our illustrious CARBON-MAN, Professor Gwyn Morgan Jenkins of Wales, Great Britain, has brought us to the High Lands of carbon research and development. Now we may call ourselves Ion Beam Modified and Carbonized Gang.

Professor Jenkins, along with Prof. D. Ila, Prof. R.L.Zimmerman, A.L. Evelyn, and E.K. Williams traveled to Buffalo, New York to attend to 21st Carbon Conference and presented three papers on our carbon related research. We all had a short trip to Toronto, Canada which was a great change of atmosphere and a terrific escape from June heat.

Alabama Materials Research Conference

The Seventh Alabama Materials Research Conference (ARMC) was hosted by AAMU this year and Prof. D. Ila, Chairman of the AMRC, asked the AAMU Chapter of MRS for organizational support. We had over 200 attendees and close to 125 papers from all major Alabama schools, government, and private agencies. In addition to that we had two papers by high school students. The attendance of this meeting was 50% more that in other years and there were several individuals from national labs and international agencies in attendance.

MRS Travels

At both the Fall and Spring MRS Meetings (held in Boston and San Francisco) AAMU had representatives at the MRS Academic Affairs Committee meeting. AAMU attendees of the Fall 1993 meeting were Profs. D. Ila, R.L. Zimmerman, N. Kukhtarev, and T. Kukhtareva and students E.K. Williams and A.L. Evelyn. On the Boston trip we had as our guest Ms. Chrissy Reynolds, a senior from Randolph High School. She attended a short course in materials characterization and was able to network with students from universities such as MIT, Caltech, Berkeley,. . .AAMU had four paper presentations in three different Symposia, all of which were accepted for publication in the MRS Proceedings. We have thoughtfully provided summaries of a couple of those papers in this issue. During the Spring '94 MRS Meeting A.L. Evelyn presented the AAMU activity report to the MRS Academic Affairs Committee. There we had, as usual, Professor D. Ila (Faculty Advisor and Chairman of MRS Membership Committee) and our (brand new) postdoctoral researcher, Dr. Hossein Maleki with us to help present three papers (all of which were accepted for publication, naturally).

Visiting Postdoctoral Researcher from Brazil

Dr. Mara R. Rizzatti, a Brazilian materials scientist from the Catholic University of Porto Alegre, received a postdoctoral research grant from the Brazilian Government to work with Professor D. Ila at AAMU, on ion beam modification of polymers such as PPS and polymeric carbon. During a training session on ion beam modification of materials presented by IBM's top scientists, Dr. Rizzatti received advise from Dr. J. Baglin (IBM) on where and with whom in USA to conduct her work, after which she contacted Prof. Ila of AAMU.

TABES 1994

AAMU Chapter of MRS has reserved a booth on 10-11 May 1994, during the Technical and Business Exhibition and Symposium (TABES) which usually has over 3000 visitors from all over the world. This year we will have a display of our chapter in addition to the MRS publications and membership drive. We also hope to have some demonstrations of interesting materials effects t help garner interest in our display.

Outreach in Conjunction with OSA

A couple of days after the TABES meeting the AAMU student chapter of the Optical Society of America will travel to two local high schools to speak to students about optics and physics and will demonstrate some optical devices and effects. Some of us materials scientist will tag along to learn from the OSA's outreach stuff and to help and to learn from the OSA's outreach experience in designing our own program.

Look For The MRS-NET

Professor Daryush Ila, our Faculty Advisor, in addition to chairing zillions of national and international committees, is the Chairman of the task Force on Electronic Information/Services of the Materials Research Society. He has informed us that by Summer 1994 the MRS will be on the Internet and will be able to not only do our usual E-Mail communication with other University Chapters and MRS headquarters, but also several other things, including on-line literature search, submissions of papers, discussions, registrations, job search, and so on. He added that the capabilities will be expanded as the Information Superhighway of the future gets more and more accessible to everybody else.

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Taylor and Williams go Hungary

by Eric K. Williams

Thomas Taylor and Eric K. Williams traveled to Balatonfured, Hungary, on the shores of Lake Balaton to present papers at the 11th International Conference on Ion Beam Analysis (IBA-11) held July 5-9, 1993. Our President, A. Leslie Evelyn, presented his paper in absentia. Faculty advisor D. Ila and visiting professor R.L. Zimmerman also presented papers and stood in for our absent leader. The journal Nuclear Instrumentational and Methods B has published the papers in a special conference issue, volume No. 85, available at fine libraries everywhere. The titles and authors for which you should look are:

• RBS and Raman spectroscopy study of heat-treatment effect on phenolformaldehyde resin by A.L. Evelyn, D. Ila, and G.M. Jenkins
• RBS, AES, EDX, AND ESCA investigation of heat treatment effects on stainless steel alloy 440C by T. Taylor, D. Ila, and J.C. Cochrane;
• Simultaneous application of (p,gamma) and (p, alpha) channeling to the detection of light elements in crystals by E.K. Williams, D. Ila, and R.L. Zimmerman
• Resonant scattering assisted light element analysis by R.L. Zimmerman, D. Ila, and C.C. Smith.

The registration fee for this conference included round trip bus transport from Budapest or Vienna, room, board, a sightseeing trip and scientific activities. Because all of the conferees spent the entire week together in the same hotel one had ample opportunity to see colleagues and make new acquaintances. The weather was good for half of the conference; which ensured that talk attendance was high whilst the sunny days allowed those who wished to take a break from all of that science to work up an appetite at the tennis court or in warm and shallow Lake Balaton.

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AAMU-MRS Members attend 8th Annual National Conference of Black Physics Students

by Thomas Taylor The 8th Annual National Conference of Black Physics Students was held at the Atlanta Radisson Hotel on February 10-13, 1994. The Conference was hosted by the School of Physics at Georgia Institute of Technology and sponsored by a number of corporate and government agencies. The NCBPS which was started in 1986 by several Black physics graduate students at MIT and Harvard is designed to develop a network within the Black physics community. The primary objective of this conference was to make Black physics students aware of academic and professional opportunities available to them by bringing important issues and developments in the field to the attention of the students. The conference provided graduate students with the opportunity to share valuable experiences related to graduate school and research with undergraduate physics students.

The conference featured many distinguished speakers including Dr. L. Nan Snow, Executive Director of the National Physics Science Consortium; Dr. Charles S. Brown, Member of the Technical Staff at AT&T Bell Laboratories; Dr. Cynthia McIntyre from the Office of Naval Research; and numerous other scientists from federal agencies, colleges and universities, and private industry. Dr. Calvin Lowe, Professor/Chairperson for the Department of Physics at Alabama A&M University presented an interesting discussion entitled "Science and Technology of Organic Solid State Materials" during the special topics session which was held on the second day of day of the conference. The other AAMU faculty member in attendance was Dr. Ravindra Lal Professor of Physics.

Over 300 students from 57 colleges and universities throughout the United States were invited to attend the conference. The conference provided a forum for undergraduate students seeking graduate studies an opportunity to obtain information from representatives from various academic institutions, in an attempt to encourage Black students to successfully pursue careers in physics at the graduate level. Alabama A&M students in attendance at this year's conference were Melvin Spurlock, Thomas Taylor, Leslie Evelyn, Eric K. Williams, Lanette Ferguson, Anthony Ololo, Yashika Forrester, Phillippia Simmons, Marcia Mitchell, Darnell Diggs, and Beverly Lipford.

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Ronald Erwin McNair (1950-1986)

(A Personality Profile)
by Leslie Evelyn

The late Ronald Erwin McNair was born in Lake City, SC, Oct 21, 1950. An astronaut and Physicist, McNair graduated from Carver High School, Lake City, in 1967. He received a bachelor's degree in physics magna cum laude from North Carolina A&T State University in 1971 and a doctorate in physics from Massachusetts Institute of Technology in 1976. He was recognized nationally for his work in the field of laser physics and was one of 35 successful applicants from a pool of 10,000 for the astronaut program in 1978. He was the second Black American to fly in space; recipient of three honorary doctorate and a score of fellowships and commendations; a sixth degree black belt in karate; an accomplished saxophonist; married the former Cheryl Moore; had two children, Reginald Ervin and Joy Cheray; and died Jan. 28, 1986 in a fiery explosion nine miles above the Atlantic along with six other crew members aboard the space shuttle challenger.

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Papers to Which AAMU-MRS Members Contributed

Presented at Fall 1993 MRS Meeting, Boston, Mass

Channeling in LiNbO3:Fe Modulated by Holographic Stress Field Superlattice

N. KUKHTAREV, T. KUKHTAREVA, D. ILA, E.K. WILLIAMS, R.L. ZIMMERMAN, AND H.J. CAULFIELD

Particle channeling is widely used for characterization of impurities and defects in crystals. On the other hand, the channeling of a photon flux through a periodic structure is less known. It has been shown that a volume phase grating with a period greater than the wavelength of light can localize light near the planes having the maximum value of refractive index.

The similarity between photon and ion channeling stems from the analogy between the Maxwell equation and the Schroedinger equations that describe propagation of photon and ion beams in coherent channeling. Zimmerman et al. have shown the effects of the electric field induced dechanneling in LiNbO3 in the form of an asymmetric narrowing of the half-angle psi(1/2), depending on the direction of the crystal and the polarity of the electric field. In this paper we will use this fundamental analogy to describe photon channeling in LiNbO3:Fe by holographic grating.

One expects that a uniform ion beam incident perpendicular to the polar axis of a LiNbO3 crystal on which a holographically produced strain field has been produced optically will penetrate the crystal in the lateral pattern of the holograph. Concomitantly, channeling between the strained crystallographic planes will cause the ions to reach non-uniform depths that also maintain that pattern. Both effects may be useful as a way to fix the pattern modification.

As a first step to test the influence of the optically produced strain fields on ion beams, we have observed the channeling of 1.03 MeV protons between the (0001) planes of LiNbO3:Fe into which a holographic grating has been introduced by interfering beams from a He-Ne laser.

The channel observed from the region that is periodically strained by the alternating persistent internal electric fields of the holograph is about 0.3 degrees narrower than that observed from the neutral region. Zimmerman et al. have observed asymmetric narrowing of the (0001) channel when external electric fields are applied perpendicular to those planes. The results here seem to be a superposition of the channel narrowing from electric fields applied alternately in the positive and negative directions.

The observed narrowing of ion beam channeling in LiNbO3:Fe holographic strain fields is qualitatively different and much larger than expected. Experiments in progress may better define the phenomenon and determine possible applications.

The success of this work can result in applications such as fixing holographic grating by ion bombardment. The typical concentration of impurity needed to record grating in LiNbO3 is 10^13/cc, which can be achieved by using an ion beam flux during exposure time and holographically induced stresses. The other spinoff of this work is a result of the small penetration depth of the ion beam, a few micrometers depending on the ions and their energy, which can produce ion-implanted waveguides with a holographically embedded coupling.

Presented at Radiation Effects on Insulators conference in Nagoya, Japan

Ion Beam Induced Carbonization of Partially Cured Phenolic Resin

D. ILA, L. EVELYN, AND G.M. JENKINS

Partially cured phenolic resin films were irradiated with N^5 ions at 6.5 MeV, He^+2 ions at 1.5 MeV and protons at 0.5 MeV. These films were prepared by spin coating and subsequent annealing at 150 C. Irradiated volumes in each sample were tested in situ for enhanced electrical conductivity and later on by Raman microprobe spectroscopy. Raman microprobe spectroscopy of the darkened phase shows development of the D and G lines which are characteristic of the production of a carbonized resin. This localized transformation, depending on the energy and type of the incident ion, occurred preferentially at a shallow depth rather than throughout the volume and is due to the direct energy transfer from beam to target, localized thermal annealing processes and sample dependent chemical reactions between stopped neutralized incident ions and the sample.

Results

As indicated in a plot(not shown) of resistivity versus the ion dose for samples bombarded with 0.5 MeV protons, 1.5 MeV alphas and 6.5 MeV nitrogen ions, the form of the resistivity/dose curve was similar for all bombarding particles. There was little effect until a critical fluence was experience; thereafter conductivity increased rapidly. The critical fluence for rapid increase in conductivity was lowest for nitrogen ions by three and four orders of magnitude.

The low critical fluence for rapid reduction in resistivity using nitrogen ions suggests that conducting aromatic layers are quickly established for incident ions with high stopping power. The high rise in conductivity found for samples irradiated with alphas and nitrogens contrasts with the decrease observed by others on irradiating fully carbonized resin. This observation and the Raman spectra from these samples suggest that localized carbonization has been effected which may eventually produce polymeric carbon

Conclusions

We have demonstrated that the partially cured phenolic resin films can be bombarded with MeV ions without causing disruption. The irradiated volume deep below the surface contains carbonized material in the form of graphite micro-crystals by measurement of a large local increase in electrical conductivity and by Raman microprobe spectroscopy.

Acknowledgements

This project is supported by NSF Grant No. EHR-9108761 and the Howard J. Foster Center for Irradiation of Materials at Alabama A&M University