# Presentation: 170602

## Focused Research GroupTwo-gap Superconductivity in Bulk Form Magnesium Diboride and its Implications for ApplicationsDMR 0514592Lead PI David Larbalestier UW and FSU

**A collaboration between groups at Arizona State University (Nate Newman and John Rowell), , Pennsylvania State University (Zi-Kui Liu and Xiaoxing Xi), the University of Puerto Rico at Mayaguez, and the University of Wisconsin (Eric Hellstrom*, David Larbalestier* and Paul Voyles)**
***now at the National High Magnetic Field Laboratory, Florida State University**

- 6 two page nuggets of the recent FRG work follow
- Thermodynamic modeling of the Mg-B-C system
- MBE films – doping effects (oxygen, Rb and Cs additions)
- Nanoscale TEM examination of champion critical field MgB2
- Improved vortex pinning by activated sintering of  MgB2 grain size
- Further enhanced pinning by milling metal diborides into MgB2
- Enhancement of connectivity of MgB2 by a novel B purification procedure
- International interactions with Italian Scientists

## Outline

**Thrust one: Improving T****c**** and H****c2**
- PSU – underlying thermodynamics
- ASU-   Rb and Cs growth
- ASU – Oxygen growth (thermal processing)
- ASC (FSU/UW) – TEM to understand high Hc2
**Thrust two: Improving microstructure**
- ASC – Combining fine grains with activated sintering
- ASC and UPRM – Milling of MeB2 to add additional pinning
- ASC and UPRM – purification
**Thrust three: Reaching out**
- ASU – Science is fun
- All – US-Italy collaborations

**Notes:**
We have several thrusts in the FRG, as befits a broad effort tackling multiple factors controlling MgB2 understanding and performance.  

One thrust is aimed at understanding and enhancing the primary superconducting properties: Tc and Hc2.  This is the more condensed matter physics portion of the work.  Most hinges on compositional considerations such as alloying or doping the lattice.  Some of that is thermodynamic modeling, some is experimental.  A third very important part of the effort to improve Hc2 involves using TEM to understand the anomalously high performance of some films made within the FRG.  That work showed this year that one key to high Hc2 is structural disorder at a scale of 10 nm or less.   

Even with high Tc and Hc2, MgB2 still needs substantial Jc improvement to compete with more established LTS materials.  There are two microstructural keys to Jc improvement: obtaining strong flux vortex pinning (by refining grains and introducing nano-second phases) and by obtaining well connected grains with clean grain boundaries.  We have advanced on both fronts by milling, and our boron purification process has substantially improved connectivity.

The third thrust of this work is outreach, and here we pay special attention to ASU’s blossoming “Science is fun” program.  We have also developed and fostered close connections with groups around the world, particularly in Brazil and Italy.  This has involved visiting students and scientists, resulting in a stronger educational experience for our students here in the USA.

## Thermodynamic Modeling of the Mg-B-C systemZi-Kui Liu, The Pennsylvania State UniversityDMR-0514592 (PI David Larbalestier)

- Using the powerful CALculation of PHAse Diagram (CALPHAD) approach integrated with first-principles calculations, we developed thermodynamic models of the Mg-B-C system.  From the isothermal section at 1000 K and ~1 Torr for the HPCVD thin films (Hybrid Physical Chemical Vapor Deposition), we predicted that the maximum solubility of carbon in MgB2 is much less than indicated in the literature.
- We predicted that MgB2C2 or graphite may form during the HPCVD process depending on the carbon content of the system. We proposed that in MgB2 thin films, the observed lattice parameter variation as a function of carbon content is not due to C-doping but actually reflects differences in the thermal expansion coefficients between MgB2 and MgB2C2 or graphite [*Saengdeejing et al., Appl. Phys. Lett., Vol.90, 2007, 151920*].

- Isothermal section of Mg-B-C at 1000 K and ~1 torr

- Normalized lattice parameters from our predictions and experiment data

**Notes:**
Thermodynamic database of Mg-B-C system has been developed through CALculation of PHAse Diagram (CALPHAD) approach. Using both existing experimental data and first-principles calculation, we can construct an accurate thermodynamic database for this system. Phase diagrams can be easily plotted from the database and provide useful information for producing MgB2. Carbon solubility in MgB2 predicted by our database is smaller that that reported in the literature.

Using our calculated phase diagrams, we can predict what phases will appear in the synthesis process. Base on prediction from our thermodynamic database, we propose a model to explain the observed lattice parameter variation as a function of carbon content of MgB2 thin films produced by HPCVD process. The calculated results agree with experimental data.

New literature on doping MgB2 shows that adding Ba, Cs or Rb increase transition temperature, so our next goal will be to create database for those exciting new ternary systems in order to further improve the properties of the MgB2 superconductor.

## Thermodynamic Modeling of the Mg-B-C systemZi-Kui Liu, The Pennsylvania State UniversityDMR-0514592 (PI David Larbalestier)

**Future work:**
- Use existing data to provide a guideline for other doping element in MgB2
**Phases Research Lab:**
- We have three undergraduate students, ten graduate students and four research fellows working on various projects such as magnesium alloys, aluminum alloys, boride, Ni-based superalloys, perovskites and diffusion in intermetallic.

- Preliminary binary phase diagrams of Mg-Ba and B-Ba

- It was shown in the literature recently that doping MgB2 with Ba, Cs and Rb can increase superconductivity transition  temperature (Tc). Right now we try to construct thermodynamic database for Mg-B-(Ba,Cs,Rb) and try to predict solubility limit of those elements.
**Current work:**
- Thermodynamic modeling of other dopants (ex. Ba, Cs and Rb) for MgB2.

**Thermodynamic Modeling of the Mg-B-C system****Zi-Kui Liu, The Pennsylvania State University****DMR-0514592 (PI David Larbalestier)**

**Notes:**
Rb, Cs and Ba have been reported to increase Tc  (A. V. Palnichenko, O. M. Vyaselev, and N. S. Sidorov, arXiv:0707.3931v3 [cond-mat.supr-con] 28 Jul 2007), though our own attempts to reproduce this have not so far been successful.

## Rb- and Cs- doping of MgB2N. Newman and J.M. Rowell, Arizona State UniversityDMR-0514592

**Palnichenko et al.* reported T****cs**** of > 55 K when  MgB****2**** powders are doped with Rb and Cs.  They did not report the doping level or any other chemical information.  **
**We found that Rb and Cs can be controllably introduced into MgB****2**** thin films at concentrations ranging from 0 to 7% by annealing at temperatures up to 300 C in quartz ampoules containing elemental alkali metals. **
**No significant change in T****c**** and H****c2**** observed, in contrast to Palnichenko’s results  **
**Our detailed Rutherford Backscattering Spectrometry investigation found significant levels of oxygen and carbon contamination introduced during doping. We also observe a large increase in resistivity and a drop in J****c**

- *Palnichenko A V, Vyaselev O M and Sidorov N S 2007 arXiv:0707.3931v3].

**Notes:**
Studies have also been made in the bulk by Rodrigues and have also not yet reproduced the Palnichenko claims of a 55K Tc – we are in contact with Palnichenko and one of the ASC scientists, Anatoly Polyanskii, will visit Palnichenko at ISSP Chernogolovka in late October to discuss.

It cannot be emphasized too strongly that confirmation of this strong enhancement of Tc in MgB2 would be very significant!

## Achieving high Hc2 by thermal processing of MgB2 deposited on low temperature substratesN. Newman and J.M. Rowell, Arizona State UniversityDMR-0514592

**novel route to obtain high H****c2**** by depositing films on low temperature substrates & then annealing at very low temperatures **
**slopes *****dHc2******/******dT***** are often larger than 1.5T/K (i.e. H****c2**** potentially >50 T)**
**This work suggests that to increase H****c2**** in MgB****2**** , maximum scattering must be achieved in materials with T****c**** of say 30 to 33K. **
**Results suggest that today the MgB****2**** wire manufacturers are using reaction temperatures that are far too high to achieve necessary carrier scattering in MgB2.**

**Thermal **
**processing**

**Notes:**
An important aspect of this work is that it gives an independent way to achieve high Hc2 beyond the bulk limit of about 35T in annealed bulk samples and perhaps without the strong degradation of connectivity that is seen in the HPCVD films of maximum Hc2 – see the TEM nugget by Voyles that addresses the structural disorder at present associated with this route to high Tc

## The influence of stoichiometry on the introduction of oxygen into MgB2 filmsN. Newman and J.M. Rowell, Arizona State UniversityDMR-0514592

- amount of oxygen incorporated in MgB2 thin films depends strongly on material’s stoichiometry.
- Rutherford Backscattering Spectrometry was used to monitor changes in oxygen incorporation resulting from exposure to: (a) ambient, (b) humid atmospheres, (c) anneals in air, and (d) anneals in oxygen.
- oxygen content in grains increases in both Mg-rich films and in films exposed to humid environments

## Effects of oxygen incorporation on Tc, Jc, & Hc2 of MgB2 filmsN. Newman and J.M. Rowell, Arizona State University DMR-0514592

_**Research impact:**_
**Oxygen incorporated *****in situ***** and *****ex situ***
**Very high J****c**** & H****c2**** (>10****7****A/cm****2**** at 0T; ~10****6**** A/cm****2**** at 4T, 4.2K) at <8 at. % oxygen)**
***dHc******2******/dT******!!***** increases w/ oxygen concentration**
**as high as 1.5T/K for *****dHc2/dT***** &***** *****53T for Hc2(0)**
**oxygen distributed both in & between grains. **
**While Tc reduces, intra-grain resistivity increases w/ increased oxygen in sample. **
**Low inter-grain connectivity obtained by *****ex situ***** oxygen incorporation suggests grain boundaries are preferentially oxidized**

_**Education:**_
**Seven grad students & 3 undergrads involved in MgB****2**** research at ASU.  **
**R. Gandikota and L. Yu graduated in 2007.   Jihoon Kim graduated in 2005.  **
_**Societal impact:**_
**The high H****c2**** and J****c**** values may enable production of high-field magnets for wide range of practical applications.****  **

## Nanoscale Superconductivity in MgB2

- Two-band superconductivity is MgB2 offers unique pathways to modify vortex structure, dynamics, and pinning, and to optimize superconductivity at high magnetic fields by introducing electron scattering.  The high physical-chemical vapor deposition method of MgB2 thin-film growth developed by Xi and Redwing can create both the cleanest MgB2 thin films and films with upper critical magnetic field *H**c2** *twice as high as any other form of MgB2.
- We have shown using high-resolution TEM that this high Hc2 arises from structural disorder at a length scale of 5-10 nm, including MgB2 domains rotated by 30 with respect to the substrate, which can be separated by an amorphous layer, as shown in the top image, and by small tilts of the c axis away from the substrate normal, as shown in the bottom image.   This small tilt may preferentially introduce scattering in the  band, consistent with the Gurevich two-band Eliashberg theory.
*Zhu et al., APL 91, 082513 (2007)*

- Nanoscale Superconductivity in MgB2

**Notes:**
The behavior of electrons in a superconductor, especially in a magnetic field, can be modified by changing the material’s structure or composition.  Magnesium diboride offers exciting new opportunities to do both because it has two subtly different sets of electrons responsible for carrying the supercurrent – electric current that flows with no resistance.  Changing the behavior of that current, especially in a magnetic field, offers the opportunity to understand the fundamental physics of superconductivity in this new material, and may provide the basis for advanced magnets for MRI and for creating extremely high magnetic fields.

Paul Voyles’ student Ye Zhu has used an electron microscope capable of seeing the positions of the atoms in this material to study its structure.  We found that MgB2 has important structure at the scale of a few nanometers, where so much attention has been focused in the physical sciences and engineering in the last decade.  The top picture shows two regions of MgB2, in the upper left and lower right, in which the atoms are arranged in a regular array.  Close examination shows, however, that the arrays are rotated by thirty degrees with respect to one another.  The jumbled-up region in between the regular arrays is the same elements arranged haphazardly to form a glass.  This glassy region will stop the flow of the supercurrent entirely.  The bottom image shows two regular, crystalline arrays bumping up against one another, but with a small tilt in the regular rows from one side of the image to the other.  The superconducting electrons travel along these regular rows of atoms, so this small tilt acts like a bumper in pinball, giving the superconducting electrons a little bump, which effects their behavior in a magnetic field. 

## Nanoscale Superconductivity in MgB2

- DMR-0514592 & DMR-0347746

- Nanoscale Superconductivity in MgB2

***Training the Nanotechnology Workforce***
- To support education in advanced microscopy techniques using TEM and STEM, Voyles has created the Electron Microscopy Database (EMdb), a web clearinghouse for high-quality educational examples.  Most teaching examples come from research, and not every teacher has the ongoing research to provide good examples for every technique.  EMdb is a way for teachers to exchange examples, including possible exercises, and a way for researchers to leverage their unpublished results for impact in the classroom.
- Since its announcement at the meeting Microscopy and Microanalysis Aug 5-8, 2007, 200+ users have registered to access EMdb, and three research groups have submitted examples.  Voyles’ has added half a dozen examples from research on MgB2.

**Notes:**
As nanotechnology takes hold in commercial fields as disparate as electronics and cosmetics, demand for technology workers skilled in the advanced microscopy techniques needed to measure materials and structures at the nanometer scale will grow.  Unfortunately, not every teacher has good examples of all the possible skills students may need, and may not even have access to all the necessary equipment to make examples.  On the other hand, specialized researchers routinely acquire hundreds of images and other measurements for every one published in the scientific literature.  The Electron Microscopy Database (EMdb) is an attempt to connect research resources to instructional need by encouraging researchers to share their unpublished examples for educational use.  Each example is posted on a web site with suggested exercises for students.

In its first month of existence, EMdb has garnered more than 200 registered users, and had examples submitted by three research groups.  This includes half a dozen examples based on research on MgB2 supported by NSF.

## Combining Improved Grain Boundary Vortex Pinning with Activated Sintering in MgB2D.C. Larbalestier and Eric Hellstrom, Florida State University/UW Madison, DMR-0514592

**Combining Improved Grain Boundary Vortex Pinning with Activated Sintering in MgB****2**D.C. Larbalestier and Eric Hellstrom, Florida State University/UW Madison, DMR-0514592

**Above:** Transmission electron image of ~10 nm MgB2 grains.

- The new superconductor MgB2 promises advances in magnet technology for MRI, fusion energy, particle accelerators, and space applications. To achieve that promise, the electric current carrying capacity (Jc) in a magnetic field must be improved.
- Jc is ultimately determined by pinning of flux vortices and then further degraded if the electrical connectivity is poor, as is generally the case in MgB2.  Flux pinning is maximized for nano-sized grains.  Electrical connectivity is maximized by high temperature sintering but at the expense of too much grain growth which reduces the density of grain boundary vortex pinning centers – creating a processing trade-off.
- By high-energy milling MgB2 powder before heat treatment we can refine grains to ~10 nm while simultaneously creating fresh surfaces which promote sintering at reduced temperature (900oC compared to 1000oC).  In this way, we produced well connected samples with < 20 nm grains and excellent Jc and enhanced upper critical field.

**Right: Result of milling (T****HT**** = 900****o****C) ******** (5x smaller grains) x (2x greater connectivity) = ****Vastly greater J****c**

**Above:** Influence of processing on superconducting properties and ultimately *J**c* as determined by this work.

**Notes:**
The usefulness of a superconductor depends on how much electric current it can carry.  At very cold temperatures and low magnetic fields, a superconductor can carry maximum current.  As temperature or magnetic field increases, the current carrying capacity (Jc) decreases.  Materials scientists work to keep Jc as high as possible at maximum temperature and magnetic field.  This work has improved Jc in the new superconductor Magnesium Diboride (MgB2) by an innovative processing method.   

In a type II superconductor, magnetic fields penetrate the material in the form of flux vortices.  A flux vortex is like a tiny pin hole where the material is normal, not superconducting.  These flux vortices are an ordinary condition of superconductivity.  Each vortex has a diameter on the scale of nanometers, and holds one flux quantum of magnetism.  When electricity is passed through the superconductor, a force called the Lorentz force pushes on the flux vortices.  If they are allowed to move, then the no-electrical-resistance state breaks down.  Therefore the flux vortices must be “pinned” in place.  One “pinning center” for flux vortices is grain boundaries.  If grain size is reduced, there are more grain boundaries.  Therefore there is stronger pinning and the material can carry more electric current.

Electric current carrying capacity (Jc) can also be limited if the material is poorly connected at the micro or nano-scale.  Since these materials are made from powders, they start out in a poorly connected state, and remain poorly connected until they are heat treated at a high enough temperature to sinter the particles together (similar to firing a clay pot).  Unfortunately, at such high temperatures (~1000oC) grains tend to grow.  Therefore, there is typically a trade-off between flux pinning and connectivity.

This work explores an innovative way to get around that trade-off.  By high-energy milling, we generate very small grains in the un-heat-treated powder.  Milling also breaks up powder particles and creates large amounts of fresh, active, surfaces.  This reduces the temperature necessary for sintering, and allows us to sinter at only 900oC – a low enough temperature that grains only grow a little bit.

The plot above shows that while high energy milling does not make much difference for samples heat treated at 1000oC (well sintered with large grains), when heat treated at 900oC the milled sample had by far the best Jc of the sample set. 

## Combining Improved Grain Boundary Vortex Pinning with Activated Sintering in MgB2 D.C. Larbalestier and Eric Hellstrom, Florida State University/UW Madison, DMR-0514592

- One PhD graduated in 2007 (Ben Senkowicz), Two current graduate students (Jian Zhou FSU, Ye Zhu UW), two undergrads Richard Mungall, Jonathan Hedstrom), one **visiting Professor from Brazil** (Durval Rodrigues Jr.), and two staff scientists (Jianyi Jiang, Anatolii Polyanskii) worked on bulk MgB2 research supported by this NSF Award.
**Outreach:**
- Senkowicz taught extensively at Camp Badger at UW and Hellstrom and Larbalestier hosted students from UPRM in their labs in each summer of the FRG.  Larbalestier hosted an RET teacher in Summer 2007.

**Societal Impact:**
- The ability to transport electric current without resistance and thus without dissipation is an important component of “green” technology.  These issues worked on in the FRG underlie the emerging use of MgB2 for the recently demonstrated helium-free MgB2 MRI machine (ASG, Italy) and potential use for space, fusion energy, and particle accelerators.

**Combining Improved Grain Boundary Vortex Pinning with Activated Sintering in MgB****2**** **D.C. Larbalestier and Eric Hellstrom, Florida State University/UW Madison, DMR-0514592

- Summer picnic of the ASC at FSU

**Notes:**
The main part of the broader Applied Superconductivity Center, to which all the Madison participants belonged, moved to the National High Magnetic Field Laboratory at Florida State University in October 2006, even though formally the FRG remains at UW where Eric Hellstrom remained too in academic year 2006-2007, before joining FSU in Fall 2007.  Paul Voyles will remain at UW and David Larbalestier remains affiliated with UW as emeritus professor.  Some 16 employees of ASC moved to FSU and by taking on new students and absorbing FSU colleagues, the new strength of ASC is about 30 technical persons of diverse background and capability.

## Enhanced Vortex Pinning in  MgB2 by addition of non-superconducting  diborides - Visiting Professor Durval Rodrigues with Eric Hellstrom and David Larbalestier - DMR-05-14592 (FRG) 

**Enhanced Vortex Pinning in  MgB****2**** by addition of non-superconducting  diborides - Visiting Professor Durval Rodrigues with Eric Hellstrom and David Larbalestier - DMR-05-14592 (FRG)**

- 	High-energy ball milling studies within the FRG have established the route to enhanced upper critical field and flux pinning by making very fine grains of order 10 nm.  Rodrigues has been investigating the effect of metal diboride MeB2 additions which further enhance *J**c* at lower fields when       Me = Zr, V, Al, and Ta.
- 	The volumetric pinning force Fp in MgB2 milled with 5at.%TaB2 was increased to the unusually high value of 15 GN/m3 at 4.2K, about twice that of pure MgB2. The red solid line is a simulation of Fp as a function of 0H using only the flux line lattice shear relation     Fp = K(T,Bc2) b1/2 (1-b)2, where K is a constant that depends on the temperature T and the upper critical magnetic field Bc2, and b=B/Bc2 is the reduced magnetic field.
- 	The understanding of the pinning mechanisms acting in the material allow us to achieve even higher critical current densities and irreversibility fields in bulk forms of MgB2, such as the wires being used for MRI machines by our Italian colleagues.

**Pure **
**MgB****2**

**TaB****2**** **
**doped**

**TaB****2**** doped**

**Pure MgB****2**

**Notes:**
In another nugget by recent PhD student Ben Senkowicz, grain refinement by high energy ball milling is introduced as a means to enhance the flux vortex pinning, thereby increasing the electrical current carrying capacity (Jc).  This work goes a step farther, using high energy milling not only to refine grains, but also to introduce dopant species of the form MB2 which act as additional flux pinning centers.  The non-superconducting metal diborides anchor flux vortices more effectively than grain boundaries and add to the important vortex pinning effect that control the current density that can pass without loss in MgB2. This has allowed us to double Jc with respect to the undoped material.

These results are very important for applications and practical use, mainly to generate high magnetic fields in magnets. To our knowledge, these pinning forces are the highest yet obtained in bulk MgB2.

## Enhanced Vortex Pinning in  MgB2 by addition of non-superconducting  diborides - Visiting Professor Durval Rodrigues with Eric Hellstrom and David Larbalestier - DMR-05-14592 (FRG) 

- 		The idea to introduce diborides as additions (doping) into MgB2 in an attempt to create intragranular and intergranular pinning centers in  MgB2  by adding non-superconducting compounds with the same hexagonal crystalline structure as MgB2. The initial diborides we chose are ZrB2, TaB2, VB2, and AlB2.
- 		Prof. Durval Rodrigues Jr., a visiting professor from the Escola de Engenharia de Lorena, Universidade de São Paulo, Lorena, SP, Brazil, came to work with the FRG for 18 months during 2006-2008.  He is using high-energy ball milling and hot isostatic pressing (HIP) heat treatments to make dense high-connectivity samples. Rodrigues is a physicist from Brazil who did part of his PhD studies at MIT. He has advised several Master and PhD theses. We expect to maintain a close collaboration between the FRG and his Brazilian group when he returns to Brazil.
- 		Aspects of this work are being done collaboratively with Professor Uwakweh’s group at UPRM.

- HIP unit

## Avoidance of atmospheric degradation of MgB2 by purification of starting B powderHellstrom, Uwakweh and Larbalestier - DMR-05-14592 (FRG) 

- When grains of B (and MgB2) are exposed to air the surface adsorbs water, O2 and CO2. Work between the University of Puerto Rico-Mayaguez and the University of Wisconsin-Madison (Senkowicz *et al.,* Supercond. Sci. Tech. 19 (2006) 1173-1177) showed that sintering MgB2 at 600-900°C that had been exposed to air affects its superconducting properties.  More exposure to air means worse connectivity.  Oxygen segregation to the MgB2 particle surface is the culprit. During sintering, it reacts to form MgO blocking conductivity across grain boundaries.
- We devised a way *(Jiang et al., Supercond. Sci. Tech. 19 (2006) L33-L36)* to form highly purified MgB2.  We remove O from the B by subliming B2O3 then react this purified B with Mg vapor in a sealed tube to form highly purified MgB2.  The figures show MgB2 made with purified B has little MgO compared to MgB2 made with unpurified B.

**Notes:**
Superconductors are composed of tiny (nanometer to micron sized) crystals called grains.  Electricity must flow freely across the grain boundaries (junctions between grains) in order for the material to be useful.  This work showed that exposure of starting Mg and B powders to air results in contamination.  This contamination can occur at any stage in powder manufacturing, handling, or storage, and is enormously expensive to prevent.  One symptom of this contamination is that electrical current-blocking MgO forms at the grain boundaries, resulting in poor performance.  As part of this work we devised an inexpensive process to remove the oxygen contamination from common boron powders, virtually eliminating the undesirable MgO grain boundary phase.

## Education:
Three graduate students and 6 undergraduates have worked on MgB2 at UPRM and Wisconsin. Ben Senkowicz finished his PhD in July 2007.   

Research impact:
After finishing the atmosphere studies, UPRM and UW worked together to refurbish a UW glove box that was transferred to UPRM so they could carryout research on MgB2 minimizing its exposure to air.

Societal impact:
The process we have developed to purify B is very simple.  It has applications beyond MgB2.  It can be used to purify B for any applications where O cannot be tolerated in the final product. 

- Three graduate students and 6 undergraduates have worked on MgB2 at UPRM and Wisconsin. Ben Senkowicz finished his PhD in July 2007.
**Research impact:**
- After finishing the atmosphere studies, UPRM and UW worked together to refurbish a UW glove box that was transferred to UPRM so they could carryout research on MgB2 minimizing its exposure to air.
**Societal impact:**
- The process we have developed to purify B is very simple.  It has applications beyond MgB2.  It can be used to purify B for any applications where O cannot be tolerated in the final product.

**Avoidance of atmospheric degradation of MgB****2**** by purification of starting B powder****Hellstrom, Uwakweh and Larbalestier - DMR-05-14592 (FRG)**

**Notes:**
The significance of this work extends beyond superconductor-related technology.  Broadly, we are studying the effects of atmospheric contamination during powder metallurgical processes involving highly reactive species (Mg and B) in a high energy environment (ball milling).  Much of our future technology (for example, aerospace and electronic materials) will be built on such technology.  This work has already resulted in a new method to cheaply purify (with respect to O) boron – a material used in microchips, solar cells, golf clubs, and fishing rods.

## ●    Two fast-paced, minds-on Science is Fun - Magnetism presentations have been developed with multiple explorations (15 and 45 minute presentations).  The associated training materials have also been developed.

**●    ****The presentations focus on the 4****th**** grade Arizona Science Education Standards via an electricity and magnetism theme. **
**●   ****Components of the presentations **
**     ****have been piloted with a diverse **
**     ****population  of  *****over  2,000 students ***
***     *****with positive feedback:**
***	******65% Hispanic***
***	******13% Native American***
***	******6% Black***** **
**●     ****We have delivered the 15 **
**        ****minute presentation to over **
**        ****1200 students so far!!!!!**
**	**

**Two-Gap Superconductivity in MgB****2**** & its Implications for Applications  *****ASU Outreach Progress : Science is Fun***

**N. Newman (co-PI), David Wright** **&** **Michael McKelvy**
**Arizona State University, ****DMR-0514592**

## ACCOMPLISHMENTS FOR

*SCIENCE IS FUN - MAGNETISM*

**Presented 15 minute magnetism presentation into Science is Fun presentations across central Arizona to over 1200 students so far!!!!**
**Field tested the full 45 minute presentation with a diverse student population.  Science is Fun Leadership Interns have presented it to under-represented student populations across central AZ**
**Trained >30 undergraduate interns and 6 leadership interns, visited over 70 schools, and gave several hundred presentations to > 18,000 K-12 students**
**4)  Collaborated with FRG partners to enhance outreach impact.**

- magnet

- Color TV

**N. Newman (co-PI), D. Wright** **&** **M. McKelvy**
**Arizona State University**
**DMR-0514592**

## International interactions with Italy in the MgB2 FRG -  Xiaoxing Xi, John Rowell and David Larbalestier - DMR-05-14592 (FRG) 

- Extensive collaborations have taken place with Italian groups in Genoa and Naples.  Three PhD students from Genoa (Valeria Braccini, Valeria Ferrando) and Naples have spent considerable time at Penn State and UW and a young postdoc, Chiara Tarantini from the Genoa group will come to FSU in the Fall for one year.  Marina Putti, Italian-side organizer of the workshop, is planning on a sabbatical at FSU in 2007-2008.

- Italy-US workshop on MgB2 held March 2-3, 2007 at the Italian Embassy Washington DC

## MgB2 is moving fast  Columbus and Ansaldo (Genoa, Italy) announced (Dec. 06) the first He-free superconducting MRI images – 20K, 0.5T on a cryocooler

- MRI component coils have OD  1.6 m

**MgB****2**** conductor technology is being pulled now by MRI applications**

**International interactions with Italy in the MgB****2**** FRG -  Xiaoxing Xi, John Rowell and David Larbalestier - DMR-05-14592 (FRG)**

**Notes:**
We have had excellent collaborations with the Genoa group both through our former PhD student Valeria Braccini who now, as an employee of the INFM lab and the University of Genoa, works in collaboration with Columbus Superconductor, the leader in making MgB2 wire.  It is clear from many informal discussions that the advances in connectivity and pinning worked on by Senkowicz are now finding their way into this product too.