(LBCO) Near the Onset of the Charge Order (CO) and Structural Transition*

The dynamics of charge-ordered states in underdoped cuprates is one of the key issues in the field. Recent work on a striped La_1.48Nd_0.4Sr_0.12CuO₄ (LNSCO) revealed several nonequilibrium effects as evidence for collective dynamics and strong pinning of domains in the CO phase [1]. Since the CO in LNSCO is stabilized by the structural LTO-LTT transition, we report a similar study on LBCO to further investigate the interplay of charge and structure. In LBCO, the LTT domain pattern is known to be determined by the pattern of the LTO twin boundaries formed at the HTT-LTO transition. Hence, we use protocols where the sample is warmed up into the LTO phase (above ~54 K) or into the HTT phase (above ~235 K) before measuring the c-axis resistance in the region of the CO and LTO-LTT transition. As in LNSCO, we find evidence of metastable states and collective dynamics in the form of avalanches. We discuss the protocol dependence of such behavior, and further report the effects of a magnetic field. [1] P. G. Baity et al., arXiv:1609.02591v2 [cond-mat] (2016).