Non-destructive characterisation of dopant spatial distribution in cuprate superconductors

• Published in: Physica. C, Superconductivity Vol. 575; p. 1353691
• Main Authors: Ţuţueanu, A.-E., Sales, M., Eliasen, K.L., Lǎcǎtuşu, M.-E., Grivel, J.-C., Kardjilov, N., Manke, I., Krzyzagorski, M., Sassa, Y., Andersson, M.S., Schmidt, S., Lefmann, K.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.08.2020; Elsevier BV
• Subjects: Crystal structure; Cuprates; Doping; High temperature superconductors; Inhomogeneity; Magnetic fields; Magnetic permeability; Phase transitions; Physical properties; Polarised neutron imaging; Spatial distribution; Spatial doping distribution; Superconductivity; Superconductors; Transition temperature; Polarised neutron imaging; Spatial doping distribution; Superconductivity; Cuprates
• ISSN: 0921-4534; 1873-2143; 1873-2143
• DOI: 10.1016/j.physc.2020.1353691

highlights•Polarised neutron imaging used to map doping variations in cuprate superconductors.•Non-destructive determination of doping in bulk superconducting sample.•Magnetic susceptibility and neutron imaging show proportional doping variations.•Travelling Solvent Floating Zone technique prone to produce inhomogeneous samples. Proper characterisation of investigated samples is vital when studying superconductivity as impurities and doping inhomogeneities can affect the physical properties of the measured system. We present a method where a polarised neutron imaging setup utilises the precession of spin-polarised neutrons in the presence of a trapped field in the superconducting sample to spatially map out the critical temperature for the phase transition between superconducting and non-superconducting states. We demonstrate this method on a superconducting crystal of the prototypical high-temperature superconductor (La,Sr)2CuO4. The results, which are backed up by complementary magnetic susceptibility measurements, show that the method is able to resolve minor variations in the transition temperature across the length of the LSCO crystal, caused by inhomogeneities in strontium doping.