1. Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, TX 77204, USA.
2. Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
3. Materials Science and Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, TX 78712, USA.
4. Department of Physics, Boston College, Chestnut Hill, MA 02467, USA.
5. Department of Physics, University of Illinois Urbana−Champaign, Urbana, IL 61801, USA.
6. Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX 78712, USA.
7. Department of Mechanical Engineering, Boston University, Boston, MA 02215, USA.
8. Department of Mechanical Engineering, University of Houston, Houston, TX 77204, USA.
9. Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
10. Department of Materials Science and Engineering, University of Illinois Urbana−Champaign, Urbana, IL 61801, USA.