Glassy Dynamics in a heavy ion irradiated NbSe2 crystal

S Eley; K Khilstrom; R Fotovat; Z L Xiao; A Chen; D Chen; M Leroux; U Welp; W K Kwok; L Civale

doi:10.1038/s41598-018-31203-0

Glassy Dynamics in a heavy ion irradiated NbSe₂ crystal

Sci Rep. 2018 Sep 3;8(1):13162. doi: 10.1038/s41598-018-31203-0.

Authors

S Eley^{1

2}, K Khilstrom³, R Fotovat³, Z L Xiao³, A Chen⁴, D Chen⁵, M Leroux^{1

3}, U Welp³, W K Kwok³, L Civale⁶

Affiliations

¹ Condensed Matter and Magnet Science, MPA, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
² Department of Physics, Colorado School of Mines, Golden, CO, 80401, USA.
³ Materials Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA.
⁴ Center for Integrated Nanotechnology (CINT), MPA, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
⁵ Materials Science and Technology Division, MST-8, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
⁶ Condensed Matter and Magnet Science, MPA, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA. lcivale@lanl.gov.

Abstract

Fascination with glassy states has persisted since Fisher introduced the vortex-glass as a new thermodynamic phase that is a true superconductor that lacks conventional long-range order. Though Fisher's original model considered point disorder, it was later predicted that columnar defects (CDs) could also induce glassiness - specifically, a Bose-glass phase. In YBa₂Cu₃O_7-x (YBCO), glassy states can cause distinct behavior in the temperature (T ) dependent rate of thermally activated vortex motion (S). The vortex-glass state produces a plateau in S(T ) whereas a Bose-glass can transition into a state hosting vortex excitations called double-kinks that can expand, creating a large peak in S(T ). Although glass phases have been well-studied in YBCO, few studies exist of other materials containing CDs that could contribute to distinguishing universal behavior. Here, we report on the effectiveness of CDs tilted ~30° from the c-axis in reducing S in a NbSe₂ crystal. The magnetization is 5 times higher and S is minimized when the field is parallel to the defects versus aligned with the c-axis. We see signatures of glassiness in both field orientations, but do not observe a peak in S(T ) nor a plateau at values observed in YBCO. Finally, we discuss the possibility that competing disorder induces a field-orientation-driven transition from a Bose-glass to an anisotropic glass involving both point and columnar disorder.