On the explanation of the paramagnetic Meissner effect in superconductor/ferromagnet heterostructures

TY - JOUR

T1 - On the explanation of the paramagnetic Meissner effect in superconductor/ferromagnet heterostructures

AU - Nagy, B

AU - Khaydukov, Yu

AU - Efremov, Dimitar

AU - Vasenko, A. S.

AU - Mustafa, L.

AU - Kim, H. -J.

AU - Keller, Evan T.

AU - Zhernenkov, K.

AU - Devishvili, A.

AU - Steitz, R.

AU - Keimer, B.

AU - Bottyán, L.

PY - 2016/10/1

Y1 - 2016/10/1

N2 - An increase of the magnetic moment in superconductor/ferromagnet (S/F) bilayers V(40 nm)/F (, Co(3 nm), Ni(3 nm)) was observed using SQUID magnetometry upon cooling below the superconducting transition temperature T C in magnetic fields of 10 Oe to 50 Oe applied parallel to the sample surface. A similar increase, often called the paramagnetic Meissner effect (PME), was observed before in various superconductors and superconductor/ferromagnet systems. To explain the PME effect in the presented S/F bilayers a model based on a row of vortices located at the S/F interface is proposed. According to the model the magnetic moment induced below T C consists of the paramagnetic contribution of the vortex cores and the diamagnetic contribution of the vortex-free region of the S layer. Since the thickness of the S layer is found to be 3-4 times less than the magnetic-field penetration depth, this latter diamagnetic contribution is negligible. The model correctly accounts for the sign, the approximate magnitude and the field dependence of the paramagnetic and the Meissner contributions of the induced magnetic moment upon passing the superconducting transition of a ferromagnet/superconductor bilayer.

AB - An increase of the magnetic moment in superconductor/ferromagnet (S/F) bilayers V(40 nm)/F (, Co(3 nm), Ni(3 nm)) was observed using SQUID magnetometry upon cooling below the superconducting transition temperature T C in magnetic fields of 10 Oe to 50 Oe applied parallel to the sample surface. A similar increase, often called the paramagnetic Meissner effect (PME), was observed before in various superconductors and superconductor/ferromagnet systems. To explain the PME effect in the presented S/F bilayers a model based on a row of vortices located at the S/F interface is proposed. According to the model the magnetic moment induced below T C consists of the paramagnetic contribution of the vortex cores and the diamagnetic contribution of the vortex-free region of the S layer. Since the thickness of the S layer is found to be 3-4 times less than the magnetic-field penetration depth, this latter diamagnetic contribution is negligible. The model correctly accounts for the sign, the approximate magnitude and the field dependence of the paramagnetic and the Meissner contributions of the induced magnetic moment upon passing the superconducting transition of a ferromagnet/superconductor bilayer.

UR - http://www.scopus.com/inward/record.url?scp=84999788902&partnerID=8YFLogxK

U2 - 10.1209/0295-5075/116/17005

DO - 10.1209/0295-5075/116/17005

M3 - Article

AN - SCOPUS:84999788902

VL - 116

JO - Europhysics Letters

JF - Europhysics Letters

SN - 1286-4854

IS - 1

M1 - 17005

ER -