Reentrant superconductivity in HoNi₅-NbN-HoNi₅ nanostructures

¹ Condensed Matter - Low Dimensional Systems Laboratory, Department of Physics, Indian Institute of Technology Kanpur - Kanpur - 208016, India
² CSIR - National Physical Laboratory - New Delhi - 110012, India

^(a) rcb@iitk.ac.in
rcb@nplindia.org

Received: 8 May 2013
Accepted: 25 August 2013

Abstract

Superconductivity (S) and ferromagnetism (F) are probed through transport and magnetization measurements in nanometer scale HoNi₅-NbN (F-S) bilayers and HoNi₅-NbN-HoNi₅ (F-S-F) trilayers. The choice of materials has been made on the basis of their comparable ordering temperatures and strong magnetic anisotropy in HoNi₅. We observe the normal state reentrant behavior in resistance vs. temperature plots of the F-S-F structures just below the superconducting transition in the limited range of HoNi₅ layer thickness d_HN () when is fixed at. The reentrance is quenched by increasing the out-of-plane () magnetic field and transport current where as in-plane () field of has no effect on the reentrance. The origin of the reentrant behavior seen here in the range is attributed to a delicate balance between the magnetic exchange energy and the condensation energy in the interfacial regions of the trilayer.