Abstract
High-pressure synthesis is increasingly being used in the search for new materials. This is particularly the case for superconductors1, but the synthesis products are difficult to analyse because they are small in size (∼50 mg) and often consist of a mixture of unknown phases exhibiting a low superconducting volume fraction. X-ray or electron diffraction cannot identify a superconductor unambiguously if it is a minority constituent. Here we report a methodology—‘scanning SQUID petrology’—that combines the use of a scanning SQUID microscope2 with petrological techniques to image and identify low concentrations of superconducting phases in complex phase assemblages. We demonstrate the power of this methodology by investigating the poorly understood origin of superconductivity in the high-pressure Sr–Cu–O system1. A Sr2CuO3 + KClO3 diffusion couple3 processed at 60 kbar and 950 °C yielded the superconductor Sr3Cu2O5Cl at the ∼3% level adjacent to the oxidizer. In addition to the unexpected participation of chlorine from an ostensibly ‘inert’ oxidizer that is commonly used in high-pressure synthesis work, the sample was highly zoned owing to limited oxygen diffusion kinetics, and contained non-superconducting Sr2CuO3.2. These contamination and diffusion problems probably affected all previous high-pressure copper oxide diffusion-couple experiments. Scanning SQUID petrology has general applicability to heterogeneous samples and is capable of detecting magnetic or superconducting phases at concentrations of less than 1 p.p.m.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout
References
Yamauchi, H., Karppinen, M. & Tanaka, S. Homologous series of layered cuprates. Physica C 263, 146–150 (1996).
Kirtley, J. R. et al. Design and applications of a scanning SQUID microscope. IBM J. Res. Dev. 39, 655–668 (1995).
Hiroi, Z., Takano, M., Azuma, M. & Takeda, Y. Anew family of copper oxide superconductors Srn+1CunO2n+1+δstabilized at high pressure. Nature 364, 315–317 (1993).
Takano, M., Takeda, Y., Okada, H., Miyamoto, M. & Kusaka, T. ACuO2(A: Alkaline earth) crystallizing in a layered structure. Physica C 159, 375–378 (1989).
Takano, M., Azuma, M., Hiroi, Z., Bando, Y. & Takeda, Y. Superconductivity in the Ba-Sr-Cu-O system. Physica C 176, 441–444 (1991).
Hiroi, Z., Takano, M., Azuma, M., Takeda, Y. & Bando, Y. Anew superconducting cupric oxide found in the Sr-Cu-O system. Physica C 185–189;, 523–524 (1991).
Azuma, M., Hiroi, Z., Takano, M., Bando, Y. & Takeda, Y. Superconductivity at 110 K in the infinite-layer compound (Sr1−xCax)1−yCuO2. Nature 356, 775–776 (1992).
Hiroi, Z., Azuma, M., Takano, M. & Takeda, Y. Structure and superconductivity of the infinite-layer compound (Ca1−ySry)1−xCuO2−z. Physica C 208, 286–296 (1993).
Adachi, S., Yamauchi, H., Tanaka, S. & Môri, N. New superconducting cuprates in the Sr-Ca-Cu-O system. Physica C 212, 164–168 (1993).
Adachi, S., Yamauchi, H., Tanaka, S. & Môri, N. High-pressure synthesis of superconducting Sr-Ca-Cu-O samples. Physica C 202, 226–230 (1993).
Zhou, X. et al. Structural and superconducting properties of the infinite-layer (Sr, Ca)1−yCuO2prepared under high pressure. Physica C 233, 30–36 (1994).
Zhou, X. et al. Structure and superconductivity in the infinite-layer Sr1−xCuO2system prepared under high pressure. Physica C 233, 311–320 (1994).
Chateau, C., Clerc, F. & Suryanarayanan, R. Preparation, structural and superconducting properties of (Ba, Sr, Ca)1−yCuO2+zobtained under high pressure. Physica C 220, 127–130 (1994).
Zhang, H. et al. Identity of planar defects in the ‘infinite-layer’ copper oxide superconductor. Nature 370, 352–354 (1994).
Prouteau, C., Strobel, P., Capponi, J. J., Chaillout, C. & Tholence, J. L. Optimization of superconductivity in the high-pressure Sr-Ca-Cu-O system. Physica C 228, 63–72 (1994).
Shaked, H. et al. Superconductivity in the Sr-Ca-Cu-O system and the phase with infinite-layer structure. Phys. Rev. B 51, 111784–11790 (1995).
Shimakawa, Y. et al. Structural study of Sr2CuO3+δby neutron powder diffraction. Physica C 228, 73–80 (1994).
Wang, Y. Y. et al. ATEM study of the incommensurate modulated structure in Sr2CuO3+δsuperconductor synthesized under high pressure A. Evolution of the incommensurate modulated structure and the electronic structure with post-heat treatment. Physica C 225, 247–256 (1995).
Zhang, H. et al. ATEM study of the incommensurate modulated structure in Sr2CuO3+xsuperconductors synthesized under high pressure B. Structural model. Physica C 225, 257–265 (1995).
Ami, T. et al. Aneutron and synchrotron X-ray scattering study of Sr2CuO3+δsynthesized under moderate pressure: a new compound related to superconducting Sr2CuO3.1. Physica C 235–240;1003–1004 (1994).
Laffez, P., Wu, X. J., Adachi, S., Yamauchi, H. & Môri, N. Synthesis of superconducting Sr2CuO3+δusing high-pressure techniques. Physica A 222, 303–309 (1994).
Mitchell, J. F., Hinks, D. G. & Wagner, J. L. Low-pressure synthesis of tetragonal Sr2CuO3+xfrom a single-source hydroxometallate precursor. Physica C 227, 279–284 (1994).
Han, P. D., Chang, L. & Payne, D. A. High-pressure synthesis of the Sr2CuO3+δsuperconductor. Observation of an increase in Tcfrom 70 K to 94 K with heat treatment. Physica C 228, 129–136 (1994).
Hodges, J. P. et al. Observation of superconductivity (Tc= 50 K) in a new tetragonal alkaline-earth cuprate Sr0.8Ba1.2CuO3+δ, synthesised at ambient pressure. Physica C 260, 249–256 (1996).
Kawashima, T. & Takayama-Muromachi, E. Superconductivity in the series of compounds Sr2Can−1CunOy(n = 1∼4) prepared under high pressure. Physica C 267, 106–112 (1996).
Smith, M. G., Manthiram, A., Zhou, J., Goodenough, J. B. & Markert, J. T. Electron-doped superconductivity at 40 K in the infinite-layer compound Sr1−yNdyCuO2. Nature 35, 549–551 (1991).
Cobb, J. L., Morosoff, A., Stuk, L. & Markert, J. T. Electron-doped infinite-layer Sr1−xLnxCuO2superconductors: Synthesis, magnetism, and transport. Physica B 194–;196;2247–2248 (1994).
Kirtley, J. R. et al. High-resolution scanning SQUID microscope. Appl. Phys. Lett. 66, 1138–1140 (1995).
Kirtley, J. R. Imaging magnetic fields. IEEE Spectrum 33, 40–48 (1996).
Yang, Y., Scott, B. A., Chen, B.-H. & Walker, D. The role of contamination in Sr-Cu-O reactions at high pressure. Physica C 275, 52–64 (1997).
Walker, D., Carpenter, M. A. & Hitch, C. M. Some simplifications to multianvil devices for high pressure experiments. Am. Mineral. 75, 1020–1028 (1990).
Walker, D. Lubrication, gasketing, and precision in multianvil experiments. Am. Mineral. 76, 1092–1100 (1991).
Jin, C.-Q. et al. Superconductivity at 80 K in (Sr, Ca)3Cu2O4+δCl2−y. Nature 275, 301–303 (1995).
Acknowledgements
We thank D. Mitzi for use of the magnetometer. Work at the Lamont-Doherty Earth Observatory of Colombia University was funded by the National Science Foundation. Research at the IBM T. J. Watson Research Centre was partially supported by the Electric Power Research Institute.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Scott, B., Kirtley, J., Walker, D. et al. Application of scanning SQUID petrology to high-pressure materials science. Nature 389, 164–167 (1997). https://doi.org/10.1038/38249
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/38249
This article is cited by
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.
