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Scanning SQUID susceptometry of a paramagnetic superconductor.
- Source :
-
Physical Review B: Condensed Matter & Materials Physics . Jun2012, Vol. 85 Issue 22, p1-11. 11p. - Publication Year :
- 2012
-
Abstract
- Scanning SQUID susceptometry images the local magnetization and susceptibility of a sample. By accurately modeling the SQUID signal we can determine physical properties such as the penetration depth and permeability of superconducting samples. We calculate the scanning SQUID susceptometry signal for a superconducting slab of arbitrary thickness with isotropic London penetration depth λ on a nonsuperconducting substrate, where both slab and substrate can have a paramagnetic response that is linear in the applied field. We derive analytical approximations to our general expression in a number of limits. Using our results, we fit experimental susceptibility data as a function of the sample-sensor spacing for three samples: (1) δ-doped SrTiO3, which has a predominantly diamagnetic response, (2) a thin film of LaNiO3, which has a predominantly paramagnetic response, and (3) the two-dimensional electron layer at a SrTiO3/LaAlO3 interface, which exhibits both types of response. These formulas will allow the determination of the concentrations of paramagnetic spins and superconducting carriers from fits to scanning SQUID susceptibility measurements. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 10980121
- Volume :
- 85
- Issue :
- 22
- Database :
- Academic Search Index
- Journal :
- Physical Review B: Condensed Matter & Materials Physics
- Publication Type :
- Academic Journal
- Accession number :
- 78584467
- Full Text :
- https://doi.org/10.1103/PhysRevB.85.224518