4,412 research outputs found
Strain induced magnetic domain evolution and spin re-orientation transition in epitaxial manganite films
The evolution of magnetic domain structure in epitaxial
LaCaMnO films on (001) NdGaO is monitored as a
function of temperature and magnetic field using Magnetic Force Microscopy. We
see two distinct regions of magnetic orientational order; one in-plane
displaying contrast-less image and the other tilted away from the film plane
forming a distinct stripe pattern. A strong domain splitting is observed at the
boundary of two regions, which is resilient to reorientation with temperature
and magnetic field. We propose a model magnetic free energy functional to
explain the mechanism of domain splitting seen in manganite films
Electronic reconstruction and enhanced superconductivity at LaNdSrCuO/LaSrCuO bilayer interface
We report enhanced superconductivity in bilayer thin films consisting of
superconducting LaNdSrCuO with 0.06
0.20 and metallic but non-superconducting LaSrCuO.
These bilayers show a maximum increase in superconducting transition
temperature () of more than 200% for = 0.06 while no change in
is observed for the bilayers with 0.20. The analysis of the critical
current and kinetic inductance data suggests 2-3 unit cells thick interfacial
layer electronically perturbed to have a higher . A simple charge transfer
model with cation intermixing explains the observed in bilayers. Still
the unusually large thickness of interfacial superconducting layers can not be
explained in terms of this model. We believe the stripe relaxation as well as
the proximity effect also influence the superconductivity of the interface
Interface superconductivity in LaNdSrCuO/LaSrCuO bilayers
We identify a distinct superconducting phase at the interface of a
LaNdSrCuO (LNSCO)/LaSrCuO
(LSCO) epitaxial bilayer system using ac screening measurements. A model based
on inter-diffusion of quasiparticles and condensate at the interface yields a
thickness of 25 nm for the interfacial layer. Two-dimensional
superconductivity of the interface layer appears to be governed by
Kosterlitz-Thouless-Berezinskii transition. A parallel magnetic field
suppresses the superconducting transition temperature of this layer with a pair
breaking parameter varying as
New Convertible Authenticated Encryption Scheme with Message Linkages
The digital signature provides the signing message with functions like authentication, integration and non-repudiation. However, in some of the applications, the signature has to be verified only by specific recipients of the message and it should be hidden from the public. For achieving this, authenticated encryption systems are used. Authenticated Encryption schemes are highly helpful to send a confidential message over an insecure network path. In order to protect the recipients benefit and for ensuring non-repudiation, we help the receiver to change the signature from encrypted one to an ordinary one. With this we avoid any sort of later disputes. Few years back, Araki et al. has proposed a convertible authenticated scheme for giving a solution to the problem. His scheme enables the recipient to convert the senders signature into an ordinary one. However, the conversion requires the cooperation of the signer. In this thesis, we present a convertible authenticated encryption scheme that can produce the ordinary signature without the cooperation of the signer with a greater ease. Here, we display a validated encryption plan using message linkages used to convey a message. For the collector's advantage, the beneficiary can surely change the encrypted signature into an ordinary signature that which anyone can check. A few attainable assaults shall be examined, and the security investigation will demonstrate that none of the them can effectively break the proposed plan
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