Project Revision
Workpackage 1 Revised
This workpackage was largely revised to account for all the reviewers comments, so a whole new description is given here.
Objectives and input to workpackage
The objective is to develop measurement methods and novel devices to characterise single molecular magnets as a means towards a readout system of a single magnetic qubit.
Description of the work
NPL, CSIC-IMM and CSIC-ICMAB are the groups involved in this workpackage.
The work of NPL will involve the development and testing of micro-SQUID and micro-Hall devices. These devices will be obtained from both inter-consortium and from external links.
The aim will be to procure state-of-the-art devices from all available source and to then characterise these devices and to use them to make quantitative measurements on nanomagnets.
In particular, in the beginning of year 2003 NPL had already obtained state-of-the-art SQUIDs from two groups, Wernsdorfer at Grenoble and Lam SCIRO. These weretested and clusters of SMM were deposited within the SQUID loops (see deliverables D1.1 and D6.1).
The best candidates for the measurements will be selected to
- go forward to making measurements on small clusters of nanomagnets, having spins of the order of 104 Bohr magnetons or less, and
- modify the devices and measurement methods such that even smaller spin systems may be analysed and the state-of-the-art measurement limits are reached.
Time resolved measurements will be made to determine the coherence of any measurement methods developed.
The applicability of these measurement devices and methods towards the readout of single magnetic qubits will be studied theoretically and, where possible, experimentally.
The main role of CSIC-IMM within the consortium is that of providing device fabrication technology for the qubits hardware. In particular, the commitment is to develop state-of-the-art ultrasensitive micro-SQUID devices and micro-Hall probes and delivery to the partners for individual nanocluster measurements.
This role and commitment have to be maintained during the next period and will require still an important effort at CSIC-IMM and considerable support from the partners (NPL and UB) in order to provide extensive characterization and feedback for theoptimisation of the technology.
An important effort on the nanoconstrictions trimming by AFM driven local oxidation of the Al and Nb superconductor layers will be maintained along the 2nd year of the project. Strong collaboration with the NPL group on this subject will be envisaged.
Project progress requires, on the other hand, a deeper involvement from CSIC-IMM in the studies of the physics controlling the ultimate quantum limits of measurements and qubit manipulation. Understanding parameters controllingdecoherence and the ability to measure and modify it as a function of hardware design is a clear further objective of CSIC-IMM. It will need again a strong interaction with the rest of the groups.
In particular, magnetic resonance experiments and techniques explored by the UB group seem to provide a promising approach in this direction. CSIC-IMM plans to contribute with the development of novel ultrasensitive magnetic resonance techniques able to measure
- magnetic moments,
- anisotropy, and
- magnetization dynamics
of individual nano-particles and molecular clusters at low temperatures.
