Field-induced electronic phase separation in the high-temperature superconductor La$_{1.94}$Sr$_{0.06}$CuO$_{4+y}

• Main Authors: Holm-Dahlin, S, Larsen, J, Jacobsen, H, Rømer, A. T, Ţuţueanu, A. -E, Ahmad, M, Grivel, J. -C, Scheuermann, R, Zimmermann, M. v, Boehm, M, Steffens, P, Niedermayer, Ch, Pedersen, K. S, Christensen, N. B, Wells, B. O, Lefmann, K, Udby, L
• Format: Journal Article
• Language: English
• Published: 26.01.2021
• Subjects: Physics - Superconductivity
• DOI: 10.48550/arxiv.2101.10672

We present a combined neutron diffraction and high field muon spin rotation ($\mu$SR) study of the magnetically ordered and superconducting phases of the high-temperature superconductor La$_{1.94}$Sr$_{0.06}$CuO$_{4+y}$ ($T_{\rm c} = 37.5(2)$~K) in a magnetic field applied perpendicular to the CuO$_2$ planes. We observe a linear field-dependence of the intensity of the neutron diffraction peak that reflects the modulated antiferromagnetic stripe order. The magnetic volume fraction extracted from $\mu$SR data likewise increases linearly with applied magnetic field. The combination of these two observations allows us to unambiguously conclude that stripe-ordered regions grow in an applied field, whereas the stripe-ordered magnetic moment itself is field-independent. This contrasts with earlier suggestions that the field-induced neutron diffraction intensity in La-based cuprates is due to an increase in the ordered moment. We discuss a microscopic picture that is capable of reconciling these conflicting viewpoints.